A Randomized Controlled Trial to Evaluate the Effectiveness of Repeated Cold- and Warm Water Immersion on Performance Recovery
Phase: NA
Conditions: Healthy
Sponsor: University of Applied Sciences and Arts of Southern Switzerland

 
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A randomised controlled trial to investigate the 
effectiveness of repeated cold and hot water baths on 
performance and recovery 
  
Clinical Study Protocol  
Effectiveness of cold and hot water baths on performance and recovery 
Study Type:  
Other Clinical Trial according to ClinO, Chapter 4 
Study Categorisation:  
Risk category A according to ClinO, Art. 61  
Study Registration:  
KEK-ZH-Nr. 2021-00546 
 
ClinicalTrials.gov (NCT04902924) 
 
Sponsor  
Thim van der Laan AG 
 
Thim van der Laan jr. 
 
Weststrasse 8 / CH- 7302 Landquart 
 
Sponsor-Investigator or Principal  University of Applied Sciences Southern Switzerland   
Investigator:  
Department of Business Economics, Health and Social Care  
 
Physiotherapy Graubünden 
 
Weststrasse 8 / 7302 Landquart 
 
+41 (0)81 300 0170  
  
 
Contact / Director of Studies  
 
Clijsen Ron, PhD  
 
University of Applied Sciences and Arts Southern Switzerland 
 
Physiotherapy Graubünden 
 
Weststrasse 8, 7302 Landquart 
 
Phone: +41 (0)81 300 01 75 
 
ron.clijsen@supsi.ch  
Investigational Product:  
Whirlpool Aspen (NetSpa)  
Certified according to European directives, regulations and 
standards (2011/65/EU, 2006/95/EC, 2004/108/EC, 2009/125/EC) 
 
 
 

 
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Protocol Version and Date:  
Study protocol – Version 06 – 28.09.2021  
  
CONFIDENTIALITY STATEMENT  
The information contained in this document is confidential and is the property of the University of Applied 
Sciences and Arts Southern Switzerland (SUPSI), Department of Business Economics, Health and 
Social Care, Physiotherapy Graubünden in Landquart-CH. The information may not - in full or in part - 
be transmitted, reproduced, published, or disclosed to others than the applicable Competent Ethics 
Committee(s) and Regulatory Authority(ies) without prior written authorisation from the sponsor except 
to the extent necessary to obtain informed consent from those who will participate in the study.  
  

 
 
 

 
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Table of Contents 
SIGNATURE PAGE(S) .......................................................................................................................... 3 
STUDY SYNOPSIS ............................................................................................................................... 8 
ABBREVIATIONS ............................................................................................................................... 18 
STUDY SCHEDULE ............................................................................................................................ 19 
1. 
STUDY ADMINISTRATIVE STRUCTURE ................................................................................... 20 
1.1 
Sponsor, Sponsor-Investigator ............................................................................................... 20 
1.2 
Principal Investigator(s) .......................................................................................................... 20 
1.3 
Statistician ("Biostatistician") ................................................................................................... 20 
1.4 
Laboratory ............................................................................................................................... 21 
1.5 
Monitoring institution ............................................................................................................... 21 
1.6 
Data Safety Monitoring Committee ......................................................................................... 21 
1.7 
Any other relevant Committee, Person, Organization, Institution ........................................... 22 
2. 
ETHICAL AND REGULATORY ASPECTS .................................................................................. 23 
2.1 
Study registration .................................................................................................................... 23 
2.2 
Categorisation of study ........................................................................................................... 23 
2.3 
Competent Ethics Committee (CEC) ...................................................................................... 23 
2.4 
Competent Authorities (CA) .................................................................................................... 23 
2.5 
Ethical Conduct of the Study .................................................................................................. 23 
2.6 
Declaration of interest ............................................................................................................. 23 
2.7 
Patient Information and Informed Consent ............................................................................. 23 
2.8 
Participant privacy and confidentiality ..................................................................................... 24 
3. 
BACKGROUND AND RATIONALE ............................................................................................. 25 
3.1 
Background and Rationale ..................................................................................................... 25 
3.2 
Investigational Product (treatment, device) and Indication ..................................................... 26 
3.3 
Preclinical Evidence ................................................................................................................ 27 
3.4 
Clinical Evidence to Date ........................................................................................................ 28 
3.5 
Dose Rationale /Medical Device: Rationale for the intended purpose in study (pre-market MD)
 
28 
3.6 
Explanation for choice of comparator (or placebo) ................................................................. 29 
3.7 
Risks / Benefits ........................................................................................................................ 29 
3.8 
Justification of choice of study population ................................................................................ 29 
4. 
STUDY OBJECTIVES ................................................................................................................. 31 
4.1 
Overall Objective ..................................................................................................................... 31 
4.2 
Primary Objective .................................................................................................................... 31 
4.3 
Secondary Objectives .............................................................................................................. 31 
4.4 
Safety Objectives ..................................................................................................................... 31 
5. 
STUDY OUTCOMES ................................................................................................................... 32 

 
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5.1 
Primary Outcome ..................................................................................................................... 32 
5.2 
Secondary outcomes ............................................................................................................... 34 
5.3 
Other Outcomes of Interest ...................................................................................................... 34 
5.4 
Safety Outcomes ..................................................................................................................... 34 
6. 
STUDY DESIGN .......................................................................................................................... 35 
6.1 
General study design and justification of design ...................................................................... 35 
6.2 
Methods of minimising bias ...................................................................................................... 35 
6.2.1 Randomization .................................................................................................................. 35 
6.2.2 Blinding procedures ........................................................................................................... 35 
6.2.3 Other methods of minimising bias ...................................................................................... 35 
6.3 
Unblinding Procedures (Code break) ....................................................................................... 35 
7. 
STUDY POPULATION ................................................................................................................. 36 
7.1 
Eligibility criteria ....................................................................................................................... 36 
7.2 
Recruitment and screening ...................................................................................................... 36 
7.3 
Assignment to study groups ..................................................................................................... 37 
7.4 
Criteria for withdrawal / discontinuation of participants ............................................................ 37 
8. 
STUDY INTERVENTION ............................................................................................................. 38 
8.1 
Identity of Investigational Products (treatment / medical device) ............................................. 38 
8.1.1 Experimental Intervention (treatment / medical device) ...................................................... 38 
8.1.2 Control Intervention (standard/routine/comparator treatment / medical device) ................. 38 
8.1.3 Packaging, Labelling and Supply (re-supply) ..................................................................... 38 
8.1.4 Storage Conditions ............................................................................................................ 39 
8.2 
Administration of experimental and control interventions ......................................................... 39 
8.2.1 Experimental Intervention .................................................................................................. 39 
8.2.2 Control Intervention ............................................................................................................ 39 
8.3 
Dose / Device modifications ..................................................................................................... 39 
8.4 
Compliance with study intervention .......................................................................................... 39 
8.5 
Data Collection and Follow-up for withdrawn participants ........................................................ 39 
8.6 
Trial specific preventive measures ........................................................................................... 40 
8.7 
Concomitant Interventions (treatments) ................................................................................... 40 
8.8 
Study Drug / Medical Device Accountability ............................................................................. 40 
8.9 
Return or Destruction of Study Drug / Medical Device ............................................................. 40 
9. 
STUDY ASSESSMENTS ............................................................................................................. 41 
9.1 
Study flow chart(s) / table of study procedures and assessments ........................................... 42 
9.2 
Assessments of outcomes ....................................................................................................... 46 
9.2.1 Assessment of primary outcome ........................................................................................ 46 
9.2.2 Assessment of secondary outcomes .................................................................................. 47 
9.2.3 Assessment of other outcomes of interest .......................................................................... 47 

 
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9.2.4 Assessment of safety outcomes ......................................................................................... 47 
9.2.5 Assessments in participants who prematurely stop the study ............................................ 48 
9.3 
Procedures at each visit ........................................................................................................... 48 
9.3.1 Single measurement.......................................................................................................... 48 
9.3.2 Multiple visits ..................................................................................................................... 48 
10. REGULATORY ASPECTS SAFETY ............................................................................................ 50 
10.1 
Local regulation/ Declaration of Helsinki ................................................................................. 50 
10.2 
(Serious) Adverse Events and notification of safety and protective measures ....................... 50 
10.3 
(Periodic) safety reporting ....................................................................................................... 51 
10.4 
Amendments …………………………………………………………………………………………. 51 
10.5 
(Premature) termination of study…………………………………………………………………… 51 
10.6. 
Insurance……………………………………………………………………………………………… 52 
11. STATISTICAL METHODS ............................................................................................................ 53 
11.1 
Hypothesis ............................................................................................................................... 53 
11.2 
Determination of Sample Size .................................................................................................. 55 
11.3 
Statistical criteria of termination of trial ..................................................................................... 56 
11.4 
Planned Analyses .................................................................................................................... 56 
11.4.1 Datasets to be analysed, analysis populations ................................................................... 56 
11.4.2 Primary Analysis ................................................................................................................ 56 
11.4.3 Secondary Analyses .......................................................................................................... 56 
11.4.4 Interim analyses ................................................................................................................. 56 
11.4.5 Safety analysis ................................................................................................................... 56 
11.4.6 Deviation(s) from the original statistical plan ...................................................................... 56 
11.5 
Handling of missing data and drop-outs ................................................................................... 56 
12. QUALITY ASSURANCE AND CONTROL ................................................................................... 57 
12.1 
Data handling and record keeping / archiving .......................................................................... 57 
12.1.1 Case Report Forms ............................................................................................................ 57 
12.1.2 Specification of source documents ..................................................................................... 57 
12.1.3 Record keeping / archiving ................................................................................................. 57 
12.2 
Data management ................................................................................................................... 57 
12.2.1 Data Management System ................................................................................................. 57 
12.2.2 Data security, access and back-up ..................................................................................... 58 
12.2.3 Analysis and archiving ....................................................................................................... 58 
12.2.4 Electronic and central data validation ................................................................................. 58 
12.3 
Monitoring................................................................................................................................ 58 
12.4 
Audits and Inspections ............................................................................................................. 58 
12.5 
Confidentiality, Data Protection ................................................................................................ 58 
12.6 
Storage of biological material and related health data ............................................................. 59 

 
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13. PUBLICATION AND DISSEMINATION POLICY ......................................................................... 60 
14. FUNDING AND SUPPORT .......................................................................................................... 61 
14.1 
Funding ................................................................................................................................... 61 
14.2 
Other Support .......................................................................................................................... 61 
15. INSURANCE................................................................................................................................. 61 
16. REFERENCES.............................................................................................................................. 62 
17. APPENDICES .............................................................................................................................. 67 
  
  
 

 
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STUDY SYNOPSIS 
Sponsor/  
Sponsor- 
Investigator  
Sponsor   
Thim van der Laan AG 
Thim van der Laan jr.  
Weststrasse 8 / CH- 7302 Landquart   
 
Investigator  
University of Applied Sciences and Arts Southern Switzerland (SUPSI)  
Department of Business Economics, Health and Social Care  
Physiotherapy Graubünden 
Attn: Ron Clijsen, PhD 
Weststrasse 8  
CH-7302 Landquart  
Study Title:  
A randomised controlled trial to investigate the effectiveness of repeated cold 
and hot water baths on performance and recovery  
Short Title / 
Study ID:  
Effectiveness of repeated cold- and hot water baths on performance and 
recovery 
Ref. 2021-00546  
Protocol Version 
and Date:  
Version 06 of 28.09.2021 
Study 
registration:  
FOPH Register SNCTP  
ClinicalTrials.gov (NCT04902924)  
Study category 
and Rationale  
Other clinical trial of risk category A according to ClinO (Chapter 4)  
This study is concerned with basic physiological research on the effects of hot 
and cold water baths on the function of the body and not about the medical 
application of the devices used. No medication is administered to the test 
subjects and no tissue samples are taken. Only non-invasive or minimally 
invasive methods are used.  
  

 
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Background and 
Rationale:  
External cooling applications have been known and used in elite sports for 
years. Hot water baths have also been used for several years, both in sports 
and in the medical field. These non-invasive interventions are becoming 
increasingly popular, as hydrotherapy is said to have positive effects before and 
after sporting activity. For example, hydrotherapy is said to contribute to 
improved regeneration after sporting activity. Literature on this topic is already 
available. However, the results are inconclusive and more randomised 
controlled trials need to be conducted to clarify the results.  
In addition to the investigations between hot and cold water, recent research in 
the field of sports shows that exposure to extreme environments (e.g. stays at 
altitude) can impair not only cognitive function but also physical performance 
and the perception of pain. To the authors' knowledge, there is limited literature 
on how physical performance affects recovery under hypoxia conditions. 
Numerous studies have already looked at cold water baths and training under 
hypoxia conditions to investigate the effects on recovery. The scientific results 
do not yet allow a clear recommendation for hydrotherapy as an accelerator of 
recovery. The extent to which training under hypoxia influences regeneration 
has only been minimally investigated. Further, randomised studies are needed 
to investigate the effects of hydrotherapy and hypoxia on the ability to 
regenerate.  
Objective(s):  
The aim of this study is to investigate the effectiveness of repeated cold and hot 
hot baths and provide new insights into the appropriate use of this form of 
application. The study investigates the effect of repeated cold and hot water 
baths on the maximum voluntary isometric muscle contraction of the thigh 
muscles, vertical jump height, inflammation parameter from venous blood, 
muscle swelling and the evaluation of subjective muscle soreness in the legs 
and perceived general exhaustion during 72 hours of recovery. As an exhaustive 
measure, the subjects must complete a total of 5 x 20 maximum vertical jumps.  

 
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Outcome(s):  
Primary outcomes  
Physiological measurements  
• 
Jump height measurement (cm)  
• 
Maximum Voluntary Isometric thigh Contraction (kg)  
• 
Muscle swelling (mm)  
• 
Blood oxygen saturation (%)  
• 
Oxygen saturation of the muscles (%)   
• 
Heart rate (bpm)  
• 
Skin temperature (°C)  
• 
Core Body Temperature (°C)  
• 
Inflammation parameters: IL6 (pg/ml), CRP (mg/dl), creatine kinase 
(U/L)  
  
Psychological measurements  
• 
Dyspnea questionnaire (mod. Borg scale)  
• 
Exhaustion questionnaire (Borg scale)  
• 
Subjective muscle soreness (VAS scale)  
• 
Thermal comfort and thermal sensation  
  
Secondary outcomes:  
none  
Study design:  
Randomised, controlled trial  
  

 
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Inclusion / 
Exclusion 
criteria:  
Inclusion Criteria  
• 
Young, healthy women aged 18 – 35 years 
• 
No surgical interventions on the musculoskeletal system in the trunk 
area and lower extremities  
• 
Anticonceptives 
Exclusion criteria  
• 
Current injuries of any kind affecting the trunk and/or lower 
extremities  
• 
Injuries to the torso and/or lower extremities that occurred less than 
one year ago  
• 
Injuries to the trunk and/or lower extremities that occurred more than 
one year ago and are still causing symptoms  
• 
Fear of cold and/or hot water intervention  
• 
Fear of hypoxia  
• 
Taking medication of any kind (even self-purchased)  
• 
Pacemakers & cardiac arrhythmias  
• 
Known circulatory problems  
• 
Positive pregnancy test  
• 
Diagnosed skeletal static deviations   
• 
Appendectomy less than 2 years ago  
• 
Raynaud's syndrome  
  
  

 
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Measurements 
and procedures:  
Subject recruitment  
The subject information and consent form are given to the test subjects. 
Questions may be asked. If the test subject agrees with the information, she will 
be asked to attend the first contact day. This includes the explanations on site, 
signing of the consent form, and the completion of the health questionnaire. The 
pregnancy test must be negative. Once all tests have been passed, an 
appointment is made for the intervention. 
Measurement  the maximum  arbitrary isometric thigh muscle contraction 
(MVIC) 
MVIC is performed on the Cor 1 – ergometer chair for biomechanical 
measurements V1.0 and is expressed in kg (www.otbioelettronica.it). The 
conduction velocity is measured using the surface electromyogram system 
EMG-USB2 from OT Bioelettronica (otbioelettronica.it), band-pass filtered 
between 10-750Hz and rectified (full-wave rectify). MVIC is measured on the 
Cor 1 ergometer chair in 90° knee flexion. The raw data of muscle activity to 
measure conduction velocity is processed using OT Bioelettronica's software 
(MISO II). The electrodes are placed according to the guidelines of Barbero et 
al. (2012) "Atlas of Muscle Innervation Zones". The measurement takes place 
directly, 24 hours, 48 hours and 72 hours after the intervention.  
Jump height measurement  
The jump height after exercise is determined using a jump height measuring 
plate designed for this purpose (Just Jump Plate, Probotics Inc., Huntsville, 
USA). The test subjects assume a standing position on the plate. To measure 
the jump height, the test subjects are allowed to start from the squatting position 
(squat jump). The arms must be positioned at the hips during the entire 
movement. The jump height is measured in cm and takes place, directly, 24 
hours, 48 hours and 72 hours after the intervention takes place. 
Skin temperature 
The 
skin 
temperature 
is 
measured 
using 
the 
iButton 
System 
(http://www.ibuttonlink.com). The self-adhesive sensors transmit the information 
about the skin temperature wirelessly to a computer. The skin temperature is 
measured immediately after the intervention. The iButtons are attached with a 
strip of tape to the following locations: center of the shoulder blade, neck (6th 
cervical vertebra), back of the hand, center of the shin, center of the thigh. The 
iButtons are removed from the affected areas during the cold or hot water bath 
and then reattached. 
Skin temperature is also recorded using the FLIR A655 sc series infrared 
camera (InfrarotTec Systems, Ranstadt, Germany). A total of seven recordings 
are taken; baseline, before, during, and after the intervention.  
Core Body Temperature  
The core body temperature is determined via the e-Celsius® Performance 
(https://www.bodycap-medical.com). This non-invasive, disposable, ingestible 
capsule continuously monitors and records core body temperature and 
transmits the data wirelessly to a monitor (BodyCAP medical, Hérouville Saint-
Clair, France). Core body temperature is measured before, during, and after the 
intervention.  
 

 
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Muscle swelling  
Muscle swelling is measured using ultrasound imaging (MyLabClassC, Esaote, 
Genoa, Italy). The images are analysed using the OsiriX DICOM viewer software 
(OsiriX, Pixmeo SARL, Switzerland). The measurements take place before, 
immediately after, 24, 48, and 72 hours after the intervention.  
Heart rate  
The heart rate is determined by means of a heart rate monitor with a chest strap 
(Polar T31, Polar Inc. Kempele, Finland). Heart rate is measured before, during, 
and immediately after the intervention.  
Oxygen saturation of the blood  
The oxygen saturation of the blood is measured with a portable pulse oximeter 
with finger clip probe (Nonin 7500, Nonin medical B.V., Plymouth, USA). This 
measurement takes place during the baseline measurements as well as during 
the jump protocol.  
Oxygen saturation of the thigh muscle  
The oxygen saturation of the muscles is measured non-invasively with a deep 
tissue 
oxygenation 
monitor 
(moorVMS-NIRS, 
moor 
instruments, 
www.moor.co.uk). For this purpose, adhesive electrodes are placed over the 
muscle. The measurement is carried out during and immediately after the 
intervention.  
Inflammation parameters  
The measurement of inflammatory parameters such as creatine kinase (CK), 
interleukin 6 (IL6) or C-reactive protein (CRP) is carried out via venous blood 
sample (approx. 6 ml) (Accutrend, Roche Diagnostic, Rotkreuz, Switzerland & 
Reflotron, Roche Diagnostic, Rotkreuz, Switzerland). The measurement is 
carried out at baseline, 24 hours, 48 hours and 72 hours after the intervention 
by trained specialists.  
Subjective muscle soreness  
The subjects reported their subjective feeling of muscle soreness on a visual 
analogue scale (VAS). The scale will be scaled from "0" (no muscle soreness 
present) to "10" (largest conceivable muscle soreness) in cm increments. The  
Measurement takes place before, 24 hours, 48 hours and 72 hours after the 
intervention.  
Subjective information on general exhaustion  
The subjects reported their subjective general feeling of exhaustion on a BORG 
scale (6 – 20). The scale will be scaled from "6" (very, very light load) to "20" 
(very, very strenuous load). The measurement takes place before the 
intervention.  

 
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Subjective information on shortness of breath  
The subjects reported their subjective shortness of breath on a BORG scale (0 
– 10). The scale will be scaled from "0" (no shortness of breath at all) to "10" 
(maximum shortness of breath). The measurement takes place before the 
intervention. 
Thermal comfort and temperature sensation  
These parameters are measured using a scale. This measurement is carried 
out before and after the intervention.  
Further processing of the data  
For further data analysis, the software MATLAB® will be used, while Excel from 
Windows® will be used for data pooling and for the graphical representation of 
the end data. All digital documents are password-protected. Paper data is stored 
in a separate, lockable filing cabinet. The data collected with Excel is given 
version numbers and stored in read-only mode. The corresponding versions are 
printed out, signed by the director of studies and filed in the above-mentioned 
filing cabinet. Only the director of studies has access to this filing cabinet.  
Study Product / 
Intervention:   
The Aspen inflatable whirlpool (NETSPA) is a certified product that complies with 
European regulations, directives and standards. 
2006/95/EC 
Low 
Voltage 
Directive, 
2004/108/EC 
(Electromagnetic 
compatibility), 2011/65/EU (restriction of the use of certain Substances in 
appliances), 2009/125/EC (ecodesign of energy-related products). All guidelines 
are in writing in the Operations Manual Chapter 1 (page 40). 
In the inflatable whirlpool, temperatures of 40°C are generated with the help of 
a heating motor. The whirlpool is already commercially available and is used in 
the private wellness area.  
 
Simulated altitude training is quickly becoming the most promising development 
in the world in terms of athletic performance and peak fitness. With the Cloud 9, 
a simulated altitude of up to 4000 m above sea level can be achieved. This 
corresponds to an oxygen partial pressure of 12.7 %. The Cloud 9 altitude 
training device is designed for all levels of athletes (including amateurs) who 
want to improve their performance. The Cloud 9 is a solid, certified product that 
complies with the European Directives on Electromagnetic Compatibility, 
Machinery Directive, Air Pressure Equipment and Low Voltage Equipment 
(89/336/EEC, 91/368/CEE, 93/68/CEE, 97/23/EC, EN61010-1).  
  

 
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Control  
Intervention (if 
applicable):  
In order to obtain high-quality study results, the subjects were exposed to only 
one experimental condition at a time. There are four experimental groups. To 
keep the quality of the study high, a randomised controlled trial design was 
chosen. 
The allocation into the groups is randomised. The data collected in this way is 
pooled by outcome or group.  
The following interventions are carried out: group rCWI with repeated cold water 
baths (1 x 10 min at 10°C to the sternum and again after 2 hours), group rHWI 
with repeated hot water baths (1 x 10 min at 40°C to the sternum and again after 
2 hours), a hypoxia group (performs the jump protocol under hypoxia and then 
lies on the back for 10 minutes) and a passive control group (lying on the back 
for 10 minutes).  
Number of 
Participants 
with Rationale:  
The power analysis with the G*Power App (Düsseldorf, North Rhine-Westphalia, 
Germany) showed that a minimum number of 33 subjects was necessary to 
ensure the statistical power (0.80) to prove a parameter difference at the 5% 
significance level. Taking into account a possible loss of 20% of the datasets 
(due to drop-out or incomplete datasets), the minimum sample size is 40 
participants. The number of subjects in this study is comparable to other studies 
in the field of thermotherapy (Kuligowski et al. 1998, Pournot et al. 2011, Vaile 
et al. 2008).  
Study Duration:  May 2021-December 2023  
Study  
Schedule:  
May-December 2021: Subject information, screening, planning, data collection  
January-August 2022: Statistics   
September-May 2023: Writing the article  
June-December 2023: Time for publication  
  

 
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Investigator(s):  
Examiner  
- Ron Clijsen, PhD1,2,3  
- Hohenauer Erich, PhD1,2,3  
- Deflorin Carlina2  
- Friday Livia2  
- Herten Miriam2  
1 University College Physiotherapy Thim van der Laan, Weststrasse 8, 7302 
Landquart  
2 University of Applied Sciences and Arts Southern Switzerland, Rehabilitation 
Research Laboratory 2rLab, Rehabilitation and Exercise Science Group, 
Department of Business Economics, Health and Social Care, Physiotherapy 
Graubünden, Weststrasse 8, 7302 Landuart  
3 Vrije Universiteit Brussels, Faculty of Physical Education and Physical 
Therapy, Pleinlann 2, 1050 Brussels 
 
Contact / Director of Studies  
Clijsen Ron, PhD  
University of Applied Sciences and Arts Southern Switzerland   
Physiotherapy Graubünden   
Weststrasse 8, 7302 Landquart  
Phone: +41 (0)81 300 01 75 
ron.clijsen@supsi.ch  
Study  
Centre(s):  
University of Applied Sciences and Arts Southern Switzerland  
Physiotherapy Graubünden  
Rehabilitation Research Laboratory 2rLab  
Rehabilitation and Exercise Science Group  
Weststrasse 8  
7302 Landquart  
Statistical  
Considerations:  
The effectiveness of repeated cold and hot water baths on recovery and 
performance is tested by: 
Repeated measures analysis of variance (MANOVA)  
Factors:  
• 
Protocol  
• 
Task (repeated cold water immersion vs. repeated hot water 
immersion, repeated cold water immersion vs. control group, repeated 
hot water immersion vs. control group, repeated cold water immersion 
vs. passive group with hypoxia conditions, repeated hot water 
immersion vs. passive group with hypoxia conditions) 
• 
Time (these factors are measured immediately after cooling/warming 
and 24 hours, 48 hours and 72 hours after the interventions).  
The significance level is set at P < 0.05, and the statistical data analysis is 
performed with SPSS 27.  

 
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GCP Statement:  This study will be conducted in compliance with the protocol, the current version 
of the Declaration of Helsinki, the ICH-GCP or ISO EN 14155 (as far as 
applicable) as well as all national legal and regulatory requirements.   
  
  
  
 

 
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ABBREVIATIONS  
  
AE  
Adverse Event   
BASEC  
Business Administration System for Ethical Committees, 
(https://submissions.swissethics.ch/en/)  
CA  
Competent Authority  
CEC  
Competent Ethics Committee  
CK  
Creatine Kinase  
CRF  
Case Report Form   
CRP  
C-reactive protein  
ClinO  
Ordinance on Clinical Trials in Human Research (in German: KlinV, in French: OClin, 
in Italian: OSRUm)  
eCRF  
Electronic Case Report Form   
CTCAE  
Common terminology criteria for adverse events  
DSUR  
Development safety update report  
GCP  
Good Clinical Practice   
IB  
Investigator's Brochure  
Ho  
Null hypothesis  
H1  
Alternative hypothesis  
HRA  
Federal Act on Research involving Human Beings (in German: HFG, in French: LRH, 
in Italian: LRUm)  
IL6  
Interleukin 6  
IMP  
Investigational Medicinal Product  
IIT  
Investigator-initiated Trial  
ISO  
International Organisation for Standardisation  
ITT  
Intention to treat  
MD  
Medical Device   
MedDO  
Medical Device Ordinance (in German: MepV, in French: ODim)  
MVIC  
Maximum voluntary isometric muscle contraction  
PI  
Principal Investigator   
SDV  
Source Data Verification   
SOP  
Standard Operating Procedure  
SPC  
SS Test  
Summary of product characteristics  
Pregnancy test  
SUSAR  
Suspected Unexpected Serious Adverse Reaction   
TMF  
Trial Master File   

 
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US  
Ultrasound  
VAS  
Visual Analog Scale  
STUDY SCHEDULE  
Table 1: Schedule  
The completion of the measurement series is planned for December 2021, and the completion of the 
entire project at the end of 2023.  
  
  
Jan  
Feb  
Mar  
Apr  
May  
Jun  
Jul  
Aug  
Sep  
Oct  
Nov  
Head  
2021    
  
  
  
 
Screening, data collection  
  
 
 
 
2022   
Statistics  
 
Writing the article  
  
 
 
 
2023   
Writing the article  
Publication  
 
 
 

 
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1. STUDY ADMINISTRATIVE STRUCTURE 
1.1 Sponsor, Sponsor-Investigator  
Thim van der Laan AG 
Weststrasse 8  
7302 Landquart  
 
Thim van der Laan jr.  
+41 (0)81 300 01 70  
t.vanderlaan@physioschule.ch  
1.2 Principal Investigator(s) 
University of Applied Sciences and Arts of Southern Switzerland  
Department of Business Economics, Health and Social Care  
Physiotherapy Graubünden   
 
Ron Clijsen, PhD  
 
Weststrasse 8  
7302 Landquart 
+41 (0)81 300 01 75 
ron.clijsen@supsi.ch  
1.3 Statistician ("Biostatistician") 
University of Applied Sciences and Arts of Southern Switzerland  
Department of Business Economics, Health and Social Care  
Physiotherapy Graubünden  
 
Erich Hohenauer, PhD  
 
Weststrasse 8  
7302 Landquart 
+41 (0)81 300 01 75 
erich.hohenauer@supsi.ch  
 
 

 
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1.4 Laboratory  
University of Applied Sciences and Arts of Southern Switzerland   
Physiotherapy Graubünden  
Rehabilitation Research Laboratory 2rLab  
Rehabilitation and Exercise Science Group  
Department of Business Economics, Health and Social Care  
University of Applied Sciences and Arts of Southern Switzerland  
  
Ron Clijsen, PhD  
ron.clijsen@supsi.ch  
  
Hohenauer Erich, PhD  
erich.hohenauer@supsi.ch  
  
Deflorin Carlina  
carlina.deflorin@supsi.ch  
  
Friday Livia  
livia.freitag@supsi.ch  
  
Herten Miriam  
miriam.herten@supsi.ch  
  
Weststrasse 8  
7302 Landquart  
Phone +41 (0)81 300 01 75  
Fax  +41 (0)81 300 01 71  
1.5 Monitoring institution  
Vrije Universiteit Brussels   
Faculty of Physical Therapy  
Prof. Peter Clarys, PhD  
 
Pleinlaan 2 1050 
Brussels 
peter.clarys@vub.ac.be  
 
1.6 Data Safety Monitoring Committee 
All data obtained from the study participants will be encoded and not passed on to other people. Personal 
data and personal details are stored in paper form in a locked filing cabinet. Only the study supervisor, 
the head of the research laboratory and concurrent study director have access, whereby the 
administration of the documents is the responsibility of the head of the research laboratory.  

 
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All digital data is encoded. This means that no conclusions can be drawn about individuals. The digital 
data is stored and archived on the institute’s internal computers and is not released to third parties. 
Employees involved in data processing have no access to the personal data and the coding of it.  
1.7 Any other relevant committee, person, organisation, institution 
The study will be conducted at the University of Applied Sciences and Arts of Southern Switzerland, 
Physiotherapy Graubünden, Weststrasse 8, CH7302 Landquart, in the research laboratory of the 
research group officially known as the Rehabilitation Research Laboratory 2rLab, Rehabilitation and 
Exercise Science Group. 
The mentioned sponsor, Thim van der Laan AG, is responsible for the management according to KlinV 
§2c.  
The test products and measuring equipment are all located in this laboratory (4th floor of the building), 
and therefore all measurements can be carried out at the same location. The room offers sufficient space 
to easily fulfil all the safety aspects described below. The room in which the whirlpools are located has 
the following dimensions: 7m x 14m x 2.5m (98 square meters or 245 cubic meters) and can be 
ventilated.  
No further studies with this arrangement are currently taking place in this experimental laboratory. No 
further studies are currently being conducted at our institute.  
No other institutes and committees are involved in this study or the authorisation or monitoring of the 
study. 
 
 
 

 
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2. ETHICAL AND REGULATORY ASPECTS   
2.1 Study registration   
The present study was primarily registered in the register ClinicalTrials.gov (NCT04902924).  
The conduct of the present study lies within the remit of the Zurich Cantonal Ethics Committee. An 
application for authorisation will be submitted. Any further conditions of the responsible ethics committee 
must be implemented in the study protocol.  
When the study protocol is submitted to the Zurich Cantonal Ethics Committee, the study is also 
registered with the Swiss Coordination Office for Research on Human Subjects (FOPH Register 
SNCTP).  
2.2 Categorisation of study  
The present study is categorized as Other Clinical Trial of Risk Category A (chapter 4). The present study 
is concerned with basic physiological research on the effects of hot and cold water baths on the function 
of the body. No medication is administered to the subjects and no tissue samples are taken. Only 
minimally invasive methods are used. Experiments are carried out with CE-certified equipment in 
accordance with the instructions for use.  
2.3 Competent Ethics Committee (CEC) 
Human research in the Canton of Graubünden falls under the remit of the Cantonal Ethics Committee 
Zurich. Changes to the study protocol are not permitted without the prior approval of the CEC, except for 
the immediate elimination of obvious risks to the participants. These must be reported to the CEC in 
accordance with section 2.10.  
Early termination or interruption of the study must be reported to the CEC within 15 days, and the regular 
end within 90 days. The final report must be submitted within one year of the end of the study. Corrections 
must be reported in accordance with section 2.10.  
2.4 Competent Authorities (CA)  
The present study falls within the remit of the Zurich Cantonal Ethics Committee. Obligations and 
deadlines can be found in the previous point.  
2.5 Ethical Conduct of the Study   
The study will be conducted in accordance with the present protocol and the current version of the 
Helsinki Declaration, the ICH-GCP.  
The CEC receives an annual report and is informed about the course of studies.  
2.6 Declaration of Interest   
The sponsor/investigator (principal investigator) has no conflict of interest of a financial nature, nor is 
there a corresponding relationship of dependency.  
2.7 Patient Information and Informed Consent  
The investigators will explain the nature and aim of the study to each participant. This also includes the 
protocol, the approximate duration, possible risks and benefits. The participant will be informed that 
participation is voluntary and that she can withdraw from the study at any time without any further 
personal consequences of any kind. Furthermore, the participant is informed about who has access to 
the personal data and how data protection is guaranteed. 

 
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Each participant will receive written subject information and the consent form with a description of the 
study with all the necessary information to be able to decide whether to participate in the study. She will 
be given enough time to read this written information at home and ask questions to the responsible 
investigator. 
The subject information and consent form is submitted to the CEC, where it must be reviewed and 
approved. 
The signed consent form must be submitted before the start of the study procedure. The participant 
should read and check them before signing. The responsible investigator will then also sign the consent 
form. Finally, the participant receives a copy of the consent form. The original signed declaration of 
consent is kept as a study document in a locked filing cabinet.  
2.8 Participant privacy and confidentiality  
The examiners ensure that the privacy of the participant is guaranteed. In particular, data protection and 
confidentiality are guaranteed, and no personal data is presented or published. The signed declaration 
of consent, as well as the completed questionnaire with the other personal details, are kept in the original 
as a study document in a locked filing cabinet.  
The digital data is encrypted and treated confidentially in accordance with the encryption (coding) 
accepted by Swissethics for a person participating in a research project; third parties are not permitted 
access to the personal data. The digital data collected will only be stored on the institute's own computers 
and will not be passed on to any external persons or transferred to other computers.  
Direct access to the personal data is only allowed to the head of the research laboratories (study 
director), the study supervisor, as well as authorised persons of the CEC.  
  
 
 

 
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3. BACKGROUND AND RATIONALE  
3.1 Background and Rationale   
Thermotherapies  
Cold therapies have long been used as a treatment after strenuous exertion (Costello et al. 2012). In 
sports medicine, cold therapy is a common intervention whose effect has already been investigated in 
many studies. Cold therapy applications are used to alleviate the symptoms of subjective muscle 
soreness and general fatigue (Ascensao et al. 2011, Bailey et al. 2007, Costello et al. 2012, Crystal et 
al. 2013, Delextrat et al. 2013, Elias et al. 2012, Eston et al. 1999, Goodall et al. 2008, Guilhem et al. 
2013, Hausswirth et al. 2011, Howatson et al. 2009, Ingram et al. 2009, Jakeman et al. 2011, King et al. 
2009, Kuligowski et al. 1998, Minett et al. 2012, Paddon-Jones et al. 1997, Pointon et al. 2011, Pointon 
et al. 2012, Pournot et al. 2011, Rowsell et al. 2009, Rupp et al. 2012, Sellwood et al. 2007, Stanley et 
al. 2013, Tseng et al. 2013). Furthermore, cold therapies are used to positively influence objective 
parameters such as creatine kinase, lactate, various interleukins or C-reactive proteins (Crowe et al. 
2007, Leal et al. 2011, Tucker et al. 2012, Pointon et al. 2012, Vaile et al. 2088, Heyman et al. 2009, 
Bastos et al. 2012, De Pauw et al. 2014, King et al. 2009, Howatson et al. 2009, Guilhem et al. 2013). 
However, cold therapy is not only used to optimise subjective and objective recovery parameters, but 
also to improve objective performance (Duffield et al. 2009, Boegard et al. 2010, Brade et al. 2014, 
Wegmann et al. 2012). Cold therapy is described as a procedure that relieves pain and specifically 
reduces inflammatory reactions following injuries and overuse. As a mechanism of action of cooling, it is 
said to have the vasoconstrictive effect, which reduces inflammatory reactions by reducing cell 
metabolism. Banfi et al. (2010) recently published results according to which whole-body cooling would 
not have a negative effect on athletes. However, little evidence was found that favoured whole-body 
cooling over "non-cooling". In contrast, Leeder et al. (2012) were able to show that cold water immersion 
is an effective strategy to alleviate subjective symptoms. These results are consistent with those of 
Bleakly et al. (2012). Wegmann et al. (2012) were able to show in their meta-analysis that pre-activity 
cooling can have an effective positive effect on endurance performance. 
Hot water immersions have been used in medicine for a wide variety of diseases for some time. 
Hydrotherapy has thermal, mechanical and chemical effects and has a vasodilatory and circulation-
promoting effect (An et al. 2019). The effect of hot water immersion on recovery after intense physical 
exertion was first studied in 1995 (Viitasalo et al. 1995). At that time, it was hypothesised that hot water 
immersions increased the release of proteins from muscle tissue into the blood, thus promoting the 
maintenance of neuromuscular performance capacity. Three years later, a research team investigated 
the effects of hot water immersions compared to cold water and contrast therapy and found that cold 
thermotherapies showed statistically significant differences on the subjects' pain reports compared to 
warm thermotherapies (Kuligowski et al. 1998). However, especially in activities that require excessive 
force production, they recommend muscle strength rather than pain perception, which should be 
considered as the decisive factor when returning to training or competition. More recent studies 
comparing hot water therapy with cold water therapy found that while cold water therapy is more effective, 
hot water therapy also showed effects on various objective recovery parameters and tests measured 
after intense exercise (Ascensão et al. 2011, Vaile et al. 2008). Different protocols, for example in relation 
to water temperature, duration and immersion depth, as well as a lack of answers regarding the effect of 
hot water immersion on recovery, still do not allow any clear conclusion to be drawn (Versey et al. 2013).  
At present, there are still too few studies in the literature that have investigated the effect of cold water 
immersion compared to hot water immersion on recovery.  
  
Hypoxia  
The best example of multiple stressors occuring in combination is when climbing to high altitudes. 
Although the percentage of oxygen remains constant at different altitudes (20.93%), the air pressure 

 
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decreases exponentially as the altitude increases. As a result, the partial pressure of oxygen in the 
arterial blood and tissues is reduced (hypoxia), leading to a deterioration in both physical and cognitive 
performance. However, in addition to the stressful effects of hypoxia, other stressors, such as 
temperature and fatigue, can also be added, which are known to significantly affect human function 
(McMorris et al. 2017).  
To the knowledge of the authors, however, there are only limited studies investigating physiological 
parameters of recovery in laboratory conditions. In addition, various patient groups also suffer from lung 
dysfunction (such as COPD) and are therefore at least partially under hypoxic conditions. With this study, 
we can contribute to understanding the psychophysiological responses of recovery under hypoxia. 
 
Aim of the study  
In this project, the effect of repeated cold water immersions (10 °C for 10 min and again after 2 hours), 
repeated hot water immersions (40°C for 10 min and again after 2 hours), a hypoxia group (jump protocol 
under hypoxia and subsequent supine position for 10 min), and a passive control group (lying still in a 
supine position for 10 min) will be compared. The influence of these interventions and their effects will 
be investigated after a maximum jump load (5 x 20 jumps). The objective recovery parameters are vertical 
jump height, MVIC of the ventral thigh muscle, heart rate, muscle swelling, skin and core body 
temperature, measurement of inflammatory parameters, oxygen saturation of the blood and thigh 
muscles. Subjective recovery parameters are the local muscle soreness data, the general exhaustion 
and shortness of breath as well as information on thermal comfort and temperature sensation. The 
parameters are measured directly and 24, 48 and 72 hours after exercise. The aim is to determine the 
effects of thermotherapy in order to be able to make recommendations. The current state of scientific 
knowledge calls for further studies to substantiate or refute effects that have already been established.  
 
3.2 Investigational Product (treatment, device) and Indication   
The Aspen whirlpool from NetSpa is an inflatable pool with four seats and a capacity of 700 litres. The 
heating of the 168cm x 168cm hot tub can be adjusted up to 42°C. The water filtration runs automatically. 
The CE marking indicates that the product fulfils the essential requirements of the European Directives 
2006/95/ EC (Low Voltage): 2004/108/ EC (electromagnetic compatibility) 2011/ 65  EU (restriction of the 
use of certain substances in equipment e) 2009/125/EC (Ecodesign of Energy-Related Products).  
 
  
Image of the Aspen whirlpool: https://www.netspa.eu/en/produit/2020-spa-netspa-aspen  
  
  
Simulated altitude training is rapidly becoming the most promising development in the world in terms of 
athletic performance and peak fitness. With the Cloud 9, a simulated altitude of up to 4000 m above sea 

 
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level can be achieved. This corresponds to an oxygen partial pressure of 12.7 %. The Cloud 9 altitude 
training device is designed for all levels of athletes (including amateurs) who want to improve their 
performance. The Cloud 9 is a solid, certified product that complies with the European Directives on 
electromagnetic compatibility, machinery directive, air pressure equipment and low voltage equipment 
(89/336/EEC, 91/368/CEE, 93/68/CEE, 97/23/EC, EN61010-1).  
 
  
Image of the Cloud 9: https://chasingtargets.eu/altitude-tent-rental-service/  
 
 
An already approved ethics application with Cloud9 has already been carried out by the research staff in 
the laboratory premises in Landquart (BASEC ID 2019-00504). The research staff also have experience 
in the field of cold water baths based on an already approved ethics application, which investigated the 
effect of cold water baths following to a muscle damage protocol (BASEC ID PB_2016-01125). 
All those present are able to carry out "first aid" measures. A fully functional and annually serviced 
defibrillator is located in the research laboratory and can be put into operation by all investigators present. 
The room in which the study takes place has the following dimensions: 7m x 14m x 2.5m (98 square 
meters or 245 cubic meters) and can be ventilated.  
3.3 Preclinical Evidence  
Various studies have already shown that cooling has a positive influence on performance and recovery 
capacity compared to non-cooling measures. These positive effects have been demonstrated both on a 
subjective level (Ascensao, 2011; Bailey, 2007; Minett, 2012; Ingram, 2009, Delextrat, 2013; Elias, 2012), 
as well as on an objective level (Tseng, 2013; Pournot, 2011; Ascensao, 2011; Pointon, 2011; Tucker, 
2012, Heyman, 2009). On the other hand, there are studies that question the effectiveness of cooling in 
terms of its effectiveness (Leal, 2011; Hassan, 2011; Jakeman, 2011).  
  
To date, only a few studies have investigated the effect of hot water immersion on recovery (Bieuzen 
2013, Kuligowski 1998, Pournot 2010, Vaille 2007, Viitasalo 1995). In one study, isometric force recovery 

 
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was found to be more effective after the hot water bath compared to other thermotherapies such as a 
cold water bath and a passive control intervention (Vaile, 2007). Pournot (2010) also found significant 
changes in subjective symptom assessment, the number of leukocytes and creatine kinase. Cold water 
baths are already used in the scientific literature for a duration of 10 minutes at a water temperature of 
10°C (Hohenauer et al 2018, Hohenauer et al 2020). However, cold water baths have also been carried 
out for up to 20 minutes at a water temperature of 10°C (Kositsky et al 2020). In the field of hot water 
baths, studies have already been carried out using water temperatures of 40°C for a duration of 40 
minutes (McIntyre et al 2021, Zurawlew et al 2015). No side effects were reported with these water baths. 
Repeated cold and hot water interventions after 2 hours could help to reduce the intracellular volume 
increase that occurs within this period (White et al 2013) after exercise. 
Studies under hypoxic conditions have already been conducted in the medical field with a wide variety 
of pathologies, such as obesity under stress (Girard, Malatesta, and Millet 2017, Park et al. 2019) and 
also with senior citizens (Pramsohler et al. 2017). In addition to physiological changes, hypoxic conditions 
can lead to psychological changes (Taylor et al. 2015). Chronic altitude exposure can further lead to 
physiological changes (Smith et al. 2014)  
It is known that cognitive and physical performance in normoxia improves with light moderate exercise 
(Chang et al. 2012). In addition, there is growing evidence that exercise can even reverse the negative 
effects of hypoxia on cognitive performance (Ando et al. 2013, Komiyama et al. 2017). 
3.4 Clinical Evidence to Date  
Current research results regarding the effects of thermotherapy and training under hypoxia conditions 
are listed in chapter 3.3.  
According to the authors' knowledge, there are currently hardly any clinical studies that contrast the 
psychophysiological effects of thermotherapy with simulated altitude training and investigate its recovery.   
3.5 Dose Rationale / Medical Device: Rationale for the intended purpose in 
study (pre-market MD)   
Doctors and physiotherapists can opt for cold treatments in their treatment, for example, to relieve pain. 
However, these professional groups not only work with patients but also with amateur and elite athletes 
and also provide them with individualised care. The project uses the Aspen hot tub from NetSpa. This is 
used within the scope of the intended application and in accordance with the operating manual. The 
applied temperatures do not pose a risk to the test subject at any time. The safety instructions are strictly 
followed.  
The temperature for hot water immersion of 40°C is generated for a maximum of 10 minutes (and again 
after 2 hours). With this setting, we are within the manufacturer's recommendations from the operating 
manual. For cold water immersion, a temperature of 10°C is chosen for 10 minutes (and again after 2 
hours). Physiotherapists, sports physicians and coaches can benefit from these findings. The question 
of whether the recovery phase can be shortened or whether performance can be increased by means of 
cooling applications is legitimate. These two parameters include not only objective values but also 
subjective information from the athlete.  
During the normobaric, hypoxic situation, an altitude of up to 4000 m.a.s.l. is simulated, which 
corresponds to an oxygen partial pressure of 12.7%. This situation is realized with the help of Cloud 9.   
  
  

 
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3.6 Explanation for choice of comparator (or placebo)  
In order to produce a high-quality study, the test subjects are each assigned to an experimental group, 
which are later compared with each other. The assignment is carried out randomly. Randomization is 
guaranteed by drawing a lot. 
Cold water bath vs. hot water bath vs. hypoxia group vs. passive control group  
Four groups are compared to each other in order to compare the effect of cold water immersion versus 
hot water immersion, as well as the hypoxia group and the passive control group. The aim is to analyse 
the efficiency of thermotherapy on the ability to recover. All groups undergo the jump protocol. Both water 
bath groups are then immersed up to the sternum in water at a temperature of 10°C or 40°C (1 x 10 min 
and after 2 hours). The hypoxia group will perform the jumping protocol under hypoxic conditions and 
will then recover for 10 minutes at room temperature in a supine position like the passive control group. 
3.7 Risks / Benefits  
For the test subjects, there is a minimal risk of overloading during the maximum jumping exercise (5 x 
20) of the ventral thigh muscles until exhaustion. The test subjects are expressly informed that they can 
stop the maximum load at any time. Furthermore, two examiners will be next to the test subject during 
the 1 min jumping exercise in order to be able to catch her in case of circulatory problems. A fully 
equipped emergency kit is in the examination room at all times during the examinations. In the event of 
circulatory problems due to hypoglycaemia, dextrose, chocolate, and Coca-Cola® Ltd. are also available 
in the examination room. The test subjects are also advised to complete the test well nourished in order 
to minimise the risk of hypoglycaemia. A fully functional defibrillator (Lifepak Express Defibrillator, 
reaplus.ch) which is accessible at all times, is available at our institution. This information is 
communicated to the test persons (subject information).  
During body cooling or heating, there is only a minimal risk for the test subjects due to the short 
application times. The test subjects enter the water baths in swimwear and without body jewellery 
(piercings, rings, necklaces, etc.). Furthermore, the test subjects should not apply skin creams or other 
cosmetics to the skin. The investigators of this study are able to operate a fully functional annually 
maintained defibrillator. An examiner is at eye level with the test subject during the entire application 
period and monitors her. The investigators in this study can competently perform "first aid" measures. A 
"first aid" kit is in the research laboratory at all times. Furthermore, any injury to the musculoskeletal 
system was defined as an exclusion criterion in order not to provoke a relapse of a past injury.  
Possible risks in the situation of hypoxic conditions are the occurrence of headaches, loss of 
consciousness, disorientation and nausea. Potentially at-risk subjects are identified by the screening 
procedure and the health questionnaire and are not included in the study. However, the risk is to be 
classified as low, as studies have already been conducted with obese patients and seniors under hypoxic 
conditions, which did not lead to any complications.  
More information on securing the test subjects can be found in chap. 8.1.1.  
The test subjects do not gain any direct benefits from participating in the study.  
 
3.8 Justification of choice of study population   
This remaining category A clinical trial (Chapter 4) will be conducted with healthy young female 
volunteers. The risk of injury is considered low in this test population.  
 
 

 
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Inclusion criteria 
Exclusion criteria 
- 
Young healthy women aged 18 - 35 years 
 
- 
No surgical interventions on the 
musculoskeletal system in the trunk area and 
on the lower extremities 
- 
Anticonceptives 
- 
Current injuries of any kind affecting the trunk 
and/ or lower extremities 
- 
Injuries to the trunk and/ or lower extremities 
that occurred less than 1 year ago 
 
- 
Injuries to the trunk and/ or lower extremities 
that occurred more than 1 year ago and are 
still causing symptoms 
- 
Fear of cold and/or hot water intervention 
- 
Fear of hypoxia 
- Taking medication of any kind (including self-
purchased medication) 
- 
Pacemakers & cardiac arrhythmias 
- 
Known circulatory problems 
- 
Positive pregnancy test 
- 
Diagnosed skeletal static deviations 
- 
Appendectomy less than 2 years ago 
- 
Raynaud's syndrome 
 
 
 
 
Before agreeing to participate in the study, the test subjects are given comprehensive information about 
the procedure and possible risks. They will also receive the information in written form and have the 
opportunity to ask questions. The informed consent form explains to them what their rights and 
obligations are if they participate. The subject information states that female subjects agree to take a 
pregnancy test (urine test) if they have decided to participate in the study. This test will be carried out 
once the test subjects have signed the consent form. The urine test will be given, received and interpreted 
by the study director. The test subjects do not have to expect any costs for this test. A positive urine test 
will result in the exclusion of this study. Only the principal investigator knows the result of the urine tests 
of the female subjects. Nobody except the head of the research laboratories (study director), the study 
supervisor, as well as authorised persons of the CEC can view this test result (see point: 2.8. 
Confidentiality and privacy). In addition, all test subjects are informed that they may withdraw from 
participation at any time without giving reasons, without any disadvantages for them. The current 
regulations of the Canton of Graubünden and those of the FOPH for protection against the coronavirus 
will be taken into account and implemented when conducting the study.  
  
  
  

 
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4. STUDY OBJECTIVES  
4.1 Overall Objective  
In this study, the effect of body cooling for a maximum of 10 minutes and renewed cooling or warming 
after 2 hours on the subjective muscle soreness and general exhaustion data as well as the objectively 
measurable MVIC of the ventral thigh muscles and the maximum vertical jump height after exhausting 
physical exertion will be investigated. In addition to the parameters already mentioned, the heart rate, 
skin temperature, core body temperature, muscle swelling and oxygen saturation of the thigh muscles 
as well as inflammation parameters of the blood are to be determined. The effects of thermal application 
will be contrasted with a hypoxia group and a passive control group and compared directly, 24 hours, 48 
hours and 72 hours after the interventions. The aim is to substantiate the state of scientific knowledge 
and to provide therapists and physicians with further insights. This study can benefit all those who work 
with amateur and elite athletes.  
4.2 Primary Objective  
In this project, the effect of post-activity cooling or warming on physiological and psychological recovery 
parameters is measured and compared to the hypoxia intervention and the passive control group.  
Physiological measurements  
• 
Jump height measurement (cm)  
• 
Maximum voluntary isometric thigh contraction (kg)  
• 
Muscle swelling (mm)  
• 
Blood oxygen saturation (%)  
• 
Oxygen saturation of the muscles (%)   
• 
Heart rate (bpm)  
• 
Skin temperature (°C)  
• 
Core Body Temperature (°C)  
• 
Inflammation parameters; IL6 (pg/ml), CRP (mg/dl), creatine kinase (U/L) 
Psychological measurements  
• 
Dyspnea questionnaire (mod. Borg scale)  
• 
Exhaustion questionnaire (Borg scale)  
• 
Subjective muscle soreness (VAS scale)  
• 
Thermal comfort and thermal sensation  
4.3 Secondary Objectives  
none 
4.4 Safety Objectives  
No short-term risks other than those discussed so far are to be expected in this study.  
 
 
 

 
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5. STUDY OUTCOMES  
5.1 Primary Outcome  
Jump height measurement  
The jump height after exercise is determined using a specially designed jump height measuring plate 
(Just Jump Plate, Probotics Inc., Huntsville, USA). The test subjects assume a standing position on the 
plate. They are allowed to start from a squatting position to measure the jump height (countermovement 
jump). The arms must be positioned at the hips during the entire movement. The measurement take 
place directly, 24 hours, 48 hours and 72 hours after the intervention.  
Muscle activity (MVIC)  
MVIC is performed on the Cor 1 – ergometer chair for biomechanical measurements V1.0 and is 
expressed in kg (www.otbioelettronica.it). The conduction velocity is measured using the surface 
electromyogram system EMG-USB2 from OT Bioelettronica (otbioelettronica.it), bandpass filtered 
between 10-750Hz and rectified (full-wave rectify). MVIC is measured on the Cor 1 ergometer chair in 
90° knee flexion. The raw data of muscle activity to measure conduction velocity is processed using OT 
Bioelettronica software (MISO II). The electrodes are placed according to the guidelines of Barbero et 
al. (2012) "Atlas of Muscle Innervation Zones". The measurement takes place immediately, 24 hours, 
48 hours and 72 hours after the intervention.  
Muscle swelling  
Muscle swelling of the thigh is measured by ultrasound imaging (MyLabClassC, Esaote, Genoa, Italy). 
The images were evaluated using the OsiriX DICOM viewer software (OsiriX, Pixmeo SARL, 
Switzerland). The measurement takes place before, directly, 24 hours, 48 hours and 72 hours after the 
intervention.  
Oxygen saturation of the blood  
The oxygen saturation of the blood is measured with a portable pulse oximeter with a finger clip probe 
(Nonin 7500, Nonin medical B.V., Plymouth, USA). This measurement takes place during the baseline 
measurements as well as during the jump protocol.  
 
  
Figure: Measurement of the oxygen content of the blood  
  
Oxygen saturation of the muscle  
The oxygen saturation (%) of the thigh muscles is measured with the tissue oxygenation monitor using 
near-infrared spectroscopy (moorVMS-NIRS, moor instruments, www.moor.co.uk). The measurement is 
non-invasive and takes place via near-infrared light. The sensors are fixed around the corresponding 

 
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muscles. The muscle oxygen saturation measurement is taken directly and 24, 48 and 72 hours after 
the intervention.  
  
Figure: Measurement of the oxygen saturation of the muscle  
  
Heart rate  
The heart rate is determined by means of a heart rate monitor with a chest strap (Polar T31, Polar Inc. 
Kempele, Finland). Blood pressure and heart rate are measured directly and 24, 48 and 72 hours after 
the intervention.  
Skin temperature  
Skin temperature is measured via the iButton system (www.ibuttonlink.com). The self-adhesive sensors 
transmit the information about the skin temperature wirelessly to a computer. Furthermore, the skin 
temperature is recorded using a thermal imaging camera (A655 sc series, FLIR, InfrarotTec Systems, 
Ranstadt, Germany). The Skin temperature is measured directly and 24, 48 and 72 hours after the 
intervention. The iButtons are attached to the following locations using a tape strip: centre of the shoulder 
blade, neck (6th cervical vertebra), back of the hand, centre of the shin and centre of the thigh. The 
iButtons are removed from the affected areas during the cold water bath or hot water bath and then 
reattached.  
Core Body Temperature  
The 
core 
body 
temperature 
is 
determined 
via 
the 
e-Celsius® 
performance 
(https://www.bodycapmedical.com). With the help of this ingestible capsule, the core body temperature 
is continuously monitored, recorded and transmits the data wirelessly to a monitor (BodyCAP medical, 
Hérouville Saint-Clair, France). Core body temperature is measured directly and 24, 48 and 72 hours 
after the intervention.  
Inflammation parameters  
The measurement of inflammatory parameters such as creatine kinase (CK), interleukin 6 (IL6) or C-
reactive protein (CRP) is carried out via a venous blood sample of approx. 6ml (Accutrend, Roche 
Diagnostic, Rotkreuz, Switzerland & Reflotron, Roche Diagnostic, Rotkreuz, Switzerland). The 
measurement takes place directly, 24 hours, 48 hours and 72 hours after the intervention by trained 
specialists.  

 
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Subjective information on breathlessness  
The subjects indicate their subjective feeling of breathlessness on a modified BORG scale (0 – 10). The 
scale will be scaled from "0" (no shortness of breath at all) to "10" (maximum breathlessness). The 
measurement takes place before the intervention.  
Subjective information on general exhaustion  
The subjects indicate their subjective general feeling of exhaustion on a BORG scale (6 – 20). The scale 
will be scaled from "6" (very, very light load) to "20" (very, very strenuous load). The measurement takes 
place before the intervention.  
Subjective muscle soreness  
The subjects reported their subjective feeling of muscle soreness on a visual analogue scale (VAS). The 
scale will be scaled from "0" (no muscle soreness present) to "10" (greatest imaginable muscle soreness) 
in cm increments. The measurements are take immediately, 24 hours, 48 hours and 72 hours after the 
intervention.  
Thermal comfort and temperature sensation  
This parameter is measured using a scale. The test subjects indicate their subjective temperature 
perception on a 9-point scale from -4 (very cold) to +4 (very hot). They then rate the thermal comfort 
between 0 (pleasant) and 4 (extremely unpleasant) on a 5-point scale. These measurements are taken 
before and after the intervention.  
5.2 Secondary outcomes  
None available.  
5.3 Other Outcomes of Interest  
None available.  
5.4 Safety Outcomes  
No further outcomes are included that serve the purpose of safety.  
Discontinuation of the experiment is the responsibility of the examiners with regard to the subject's 
resilience. If this is judged to be too low, the examiner can stop the experiment.  
If the test subject does not feel well according to her own subjective assessment, she can stop the 
experiment and withdraw participation in the study. If the cold application is unacceptable for the test 
subject, she can discontinue the application. She will not suffer any disadvantages as a result.  
The current regulations of the Canton of Graubünden and those of the FOPH for protection against the 
coronavirus will be taken into account and implemented when conducting the study.  
 
  
 
 

 
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6. STUDY DESIGN   
6.1 General study design and justification of design   
Randomized, controlled trial  
This is a remaining clinical trial in risk category A (Chapter 4).  
The group size of the participants is N = 60 people. Group allocation is randomised.   
6.2 Methods of minimising bias  
All measurements are carried out and recorded in a standardized manner by the same tester. The 
laboratory conditions are always the same.  
6.2.1  
Randomsation   
The allocation to the different groups (cold water bath, hot water bath, hypoxia, control group) takes place 
randomly by drawing of a lot. 
6.2.2  
Blinding procedures   
Blinding the participants is not possible in this study. The investigators are blinded by adding another 
investigator who operates the apparatus. The responsible statistician is blinded and has no access to 
the personal data of the test subjects and is not present when the data is collected.  
6.2.3  
Other methods of minimising bias   
The content of the dialogue between the test subjects and the examiner is kept to a minimum.  
6.3 Unblinding Procedures (Code break)   
There is no provision for cancelling the statistician’s blindness.  
Unblinding of the investigators and/or the study participants is only permitted if an unforeseen event or 
medical problems occur during or after completion of the study participation in a subject which may be 
attributable to participation in the study. 
In the event of adverse events (AEs) occurring during or shortly after study participation that may be 
attributable to the intervention, the principal investigator may, at his or her discretion, immediately unblind 
the study participant and the attending investigators to ensure adequate treatment of the study 
participant.  
In the case of incidents (AE) that occur for longer than 24 hours, clarification by a doctor is mandatory 
and a medical certificate is required for the cancellation of the blindness. Data may then also be passed 
on to the attending physician with the consent of the study participant concerned. This approach is 
justified, as no life-threatening incidents are to be expected as a result of the interventions used here.  
 
  
 
 

 
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7. STUDY POPULATION  
7.1 Eligibility criteria 
Inclusion criteria 
Exclusion criteria 
- 
Young healthy women aged 18 - 35 years 
 
- 
No surgical interventions on the 
musculoskeletal system in the trunk area 
and on the lower extremities 
- 
Anticonceptives 
- 
Current injuries of any kind affecting the 
trunk and/ or lower extremities 
- 
Injuries to the trunk and/ or lower 
extremities that occurred less than 1 year 
ago 
- 
Injuries to the trunk and/ or lower 
extremities that occurred more than 1 year 
ago and are still causing symptoms 
- 
Fear of cold and/or hot water intervention 
- 
Fear of hypoxia 
- Taking medication of any kind (including 
self-purchased medication) 
- 
Pacemakers & cardiac arrhythmias 
- 
Known circulatory problems 
- 
Positive pregnancy test 
- 
Diagnosed skeletal static deviations 
- 
Appendectomy less than 2 years ago 
- 
Raynaud's syndrome 
 
 
To our knowledge, only a few studies have so far investigated the physiological response or recovery 
after a hot/ cold water bath, hypoxia and control treatment in women. This is consistent with the 
significantly underrepresented female participation in the wider sports and exercise medicine literature 
(Costello et al. 2014). In addition, a recent Cochrane review on whole-body cryotherapy concluded that 
the existing literature on cryotherapy may not be applicable to women and warrants future research on 
female participants in this area (Costello et al. 2015). In addition, the altered hormone status during the 
female cycle (e.g., estrogen) and anthropometric differences (e.g., fat distribution and total body fat) 
could lead to differences according to a muscle-damaging protocol in women.  
 
7.2 Recruitment and screening  
Recruitment  
It is published on the website (homepage & Facebook) of Thim van der Laan University College 
Physiotherapy and the University of Applied Sciences and Arts of Southern Switzerland (SUPSI). The 
exact texts have been prepared according to the checklist of the Cantonal Ethics Commission Zurich. 
 

 
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As advertisements (text visible):  
• 
Homepage of the Thim van der Laan School of Physiotherapy: www.physioschule.ch and 
SUPSI: www.supsi.ch  
• 
Facebook page of the Thim van der Laan Physiotherapy School:  
https://www.facebook.com/physioschule and SUPSI: 
https://www.facebook.com/supsi.physiotherapie/ 
 
Screening  
During the initial contact, the potential participants are informed about the procedures and risks of the 
study, as well as its conditions and the amount of compensation. A checklist for contacting them by 
telephone serves as a basis.  
During the first telephone contact, a questionnaire to determine the suitability as a study participant is 
completed by the study management. In advance, it is explained to the subject that answering the 
questions is voluntary and can be interrupted at any time and that all registered information will be deleted 
immediately if they decide not to participate in the study.  
Advertisements, questionnaires and checklists for the first contact can be found in the enclosure.  
  
7.3 Assignment to study groups  
Group allocation is carried out secretly with the help of a ticket in a sealed envelope, which is drawn 
under the supervision of the study director. This lot indicates whether the test subject is undergoing the 
cold water bath, hot water bath, hypoxia or control intervention.  
 
7.4 Criteria for withdrawal / discontinuation of participants  
If a participant withdraws from the study, the allocation lot is returned to the pot in a new envelope and a 
new participant is sought.  
The already completed consent form is kept in the locked filing cabinet. If consent is withdrawn, the data 
and samples already collected must be included in the analysis for scientific and safety reasons. These 
will only be anonymised after the analysis (Art. 9 ClinO).  
The conditions for discontinuing the trial were described in chap. 5.4. There is no disadvantage for the 
participants if they discontinue their participation in the study.  
  
  
 
 

 
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8. STUDY INTERVENTION 
8.1 Identity of Investigational Products (treatment / medical device) 
8.1.1  Experimental Intervention (treatment / medical device)  
Both application devices (Cloud9 and Whirlpool Aspen) are certified products.  
Whirlpool Aspen  
The Aspen Whirlpool is an inflatable water pool with four seats and a capacity of 700l. The heating of the 
168cm x 168cm whirlpool can be adjusted up to 42°C The water filtration runs automatically. The CE 
marking indicates that the product meets the essential requirements of the European Directives 
2006/95/EC (Low Voltage), 2004/108/EC (electromagnetic compatibility) 2011/65/EU (restriction of the 
use of certain substances in appliances e) 2009/125/EC (ecodesign of energy-related products).  
Securing the test subjects  
Only subjects who have completed the health questionnaire without risk factors will be admitted to the 
study. In this way, risk factors are recognised at an early stage and the subjects for the study are not 
recruited.  
The examiner is in direct contact with the subject at all times. The examiner is at eye level with the test 
subject and monitors the procedure. With their signed consent form, the test subjects declare that they 
have already taken a pregnancy test (urine test). This test is handed out, collected and interpreted by 
the head of the study. Only the principal investigator, the study supervisor and authorized employees of 
the CEC can view this test result. The thermo- or hypoxia application can be discontinued by the 
investigator at any time. If the thermal or hypoxia application is perceived as unpleasant by the test 
subjects, they can cancel the application at any time. Therefore, there is only a minimal risk for the test 
subjects. Furthermore, a fully functional and annually maintained defibrillator is available at the time of 
the study. All research staff and investigators can operate this defibrillator and have the competence of 
"first aid" measures. For these reasons, the presence of a doctor is not required. The test subjects are 
only allowed to enter the interventions without metal body jewellery (no piercings, rings, necklaces, etc.). 
Furthermore, the test subjects are advised to refrain from skin creams or other skin cosmetics. This is 
also evident in the subject information.  
8.1.2  Control Intervention (standard/routine/comparator treatment / medical device)   
Hypoxia group  
With the Cloud 9, a simulated altitude of 2700 m above sea level and 4000 m above sea level can be 
achieved. This corresponds to an oxygen partial pressure of 15.0% and 12.7% respectively. The Cloud 
9 altitude training device is intended for anyone (including amateurs) who wants to inprove their 
performance. The Cloud 9 is a solid, certified product that complies with the European Directives on 
electromagnetic compatibility, Machinery Directive, air pressure equipment and low voltage equipment 
(89/336/EEC, 91/368/CEE, 93/68/CEE, 97/23/EC, EN61010-1).  
Control group  
The control group will lie on their backs for 10 minutes after the jump protocol.  
8.1.3  Packaging, Labelling and Supply (re-supply)   
The Whirlpool Aspen from NetSpa complies with European directives (2006/95/EC, 2004/108/EC, 
2011/65/EU, 2009/125/EC). The Cloud 9 is a certified product according to European directives 
(89/336/EEC, 91/368/CEE, 93/68/CEE, 97/23/EC, EN61010-1).  
 
 
 

 
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8.1.4  Storage Conditions   
The whirlpools are kept in a room at room temperature and low humidity all year round. The room in 
which the whirlpools are located is fully ventilated and has the following dimensions: 7m x 14m x 2.5m 
and thus complies with the specifications in the operating manual.  
The Cloud 9 can be stored both outside in the dry and inside a room. The equipment is located inside 
our laboratory for the duration of the measurements and is only accessible to laboratory staff.  
8.2 Administration of experimental and control interventions   
As no prescription drugs and only minimally invasive methods are used, the experiment is not discussed 
further in chapters 8.2-8.4 and reference is made to cChapter 9.  
8.2.1  Experimental Intervention   
Cold water immersion  
Test subjects in this group are asked to take a cold water bath after carrying out the jump protocol. The 
application lasts 10 minutes (and is repeated after 2 hours) at a water temperature of 10°C. In a sitting 
position, the water level must reach the sternum.  
Hot water immersion  
Test subjects in this group are asked to take a hot water bath after carrying out the jump protocol. The 
application lasts 10 minutes (and is repeated after 2 hours) at a water temperature of 40°C.  In a sitting 
position, the water level must reach the sternum.  
In all experimental interventions, an examiner is located directly next to the test person for monitoring at 
all times.  
8.2.2  Control Intervention  
Hypoxia group  
The subjects of the hypoxia group will perform the jump protocol under hypoxia, which is generated with 
the Cloud 9. This intervention is used to determine the physiological effect under hypoxic conditions. 
Control group  
The test subjects of the control group are in our laboratory and are asked to lie on their back for 10 
minutes after completing the jump protocol. 
During all control interventions, an examiner is located directly next to the test person for monitoring at 
all times.  
8.3 Dose / Device modifications   
All participants will be treated with the same duration or dosage within their group.  
8.4 Compliance with study intervention 
The test subjects are only motivated to perform MVIC and the jump height measurement in order to keep 
their compliance high. The rest of the communication is kept to a minimum. Only study-related 
conversations are conducted in order not to influence the psychophysiological effects and to ensure 
homogeneity.  
 
8.5 Data Collection and Follow-up for Withdrawn Participants  
If consent is withdrawn, the data and samples already collected must be included in the analysis for 
scientific and safety reasons. These are only anonymised after the analysis (Art. 9 ClinO).  

 
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There is no disadvantage for the participants if they discontinue their participation in the study and no 
further interventions are necessary for follow-up treatment.  
If study participation was discontinued due to a reaction occurring during study participation, this will be 
recorded and reported to the sponsor investigator (head of the research laboratory), study director and 
supervisor of the study. If medical treatment is required, the report will be forwarded to the business 
liability insurance of Thim van der Laan AG (Basler Versicherung) to ensure the appropriate follow-up 
treatment.  
8.6 Trial specific preventive measures  
The questionnaire asks about the intake of medication. In addition, the test subjects agree 
to undergo a pregnancy test (urine test) by signing the consent form. This test is handed 
over, explained, received and interpreted by the head of the study (Ron Clijsen, PhD). They 
do not have to pay any costs for it – the test is provided to them free of charge. A positive 
pregnancy test leads to the exclusion of this study. Only the principal investigator, the 
study supervisor and authorised persons of the ethics committee can view this test result. 
No one else will know the result of this test. If deviations in the statics are visible but not 
medically diagnosed, the study director reserves the right to measure them (leg length 
difference, scoliosis angle) and to exclude test subjects from participation.  
 
8.7 Concomitant Interventions (treatments)   
No further side effects are expected as a result of participation in the study. 
8.8 Study Drug / Medical Device Accountability   
The experiments take place exclusively in the research laboratory of the University of 
Applied Sciences and Arts of Southern Switzerland, Physiotherapy Graubünden, in 
Landquart. This means that there is no transport of the products and measuring devices 
used. There is therefore no liability for the transport of the product. 
 
8.9 Return or Destruction of Study Drug / Medical Device   
The Cloud 9, as well as the two Aspen whirlpools, were acquired by the research 
department of the "University of Applied Sciences and Arts of Southern Switzerland" and 
will remain in the research laboratory after completion of the measurements.  
 
 
 
 

 
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9. STUDY ASSESSMENTS  
9.1 Study flow chart(s) / table of study procedures and assessments  
The test subject information is sent to the test subjects' homes in advance or given to them personally 
1. Subject Information & Informed Consent  
30 min (questions and ambiguities will be discussed individually) 
2. Preparation of the test person  
15 min  
3. Executing the test protocol 
 

 
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Test protocol: Time required – maximum 255 min  
Cold Water Immersion vs. Hot Water Immersion vs. Hypoxia Group vs. Passive Control Group  
Cold water immersion  
1.) Baseline  
Informed consent, written consent, 
review of inclusion/exclusion criteria, 
health questionnaire, pregnancy test 
Heart rate 
Skin/ core body temperature  
Oxygen saturation (blood, muscle)  
Inflammation parameters  
VAS & BORG 
thermal comfort and thermal 
sensation 
US  
3 x Vertical Jumps  
3 x MVIC  
=30 min  
  
2.) Jump protocol  
5 x 20 max vertical jumps 
after 30sec  
Heart rate  
Skin/ core body temperature  
Hot water immersion  
1.) Baseline  
Informed consent, written consent, 
review of inclusion/exclusion criteria, 
health questionnaire, pregnancy test 
Heart rate 
Skin/core body temperature  
Oxygen saturation (blood, muscle)  
Inflammation parameters  
VAS & BORG thermal comfort and 
thermal sensation 
US  
3 x Vertical Jumps  
3 x MVIC  
=30 min  
  
2.) Jump protocol  
5 x 20 max vertical jumps 
after 30sec  
Heart rate  
Skin/ core body temperature  
Hypoxia Intervention  
1.) Baseline  
Informed consent, written consent, 
review of inclusion/exclusion criteria, 
health questionnaire, pregnancy test 
Heart rate 
Skin/core body temperature  
Oxygen saturation (blood, muscle)  
Inflammation parameters  
VAS & BORG thermal comfort and 
thermal sensation  
US  
3 x Vertical Jumps  
3 x MVIC  
=30 min  
  
2.) Jump protocol under hypoxia 
5 x 20 max vertical jumps 
after 30sec  
Heart rate  
Skin/ core body temperature  
Passive Control Intervention  
1.) Baseline  
Informed consent, written consent, 
review of inclusion/exclusion criteria, 
health questionnaire, pregnancy test 
Heart rate 
Skin/core body temperature  
Oxygen saturation (blood, muscle)  
Inflammation parameters  
VAS & BORG thermal comfort and 
thermal sensation 
US  
3 x Vertical Jumps  
3 x MVIC  
=30 min  
  
2.) Jump protocol  
5 x 20 max vertical jumps 
after 30 sec  
Heart rate  
Skin/ core body temperature  

 
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Oxygen saturation (blood, muscle)  
Mod. BORG & BORG  
=30 min  
  
3.) Cold water immersion  
10 min at 10°C   
Heart rate  
Skin/core body temperature  
Oxygen saturation (muscle)  
Thermal comfort and  
Temperature sensation  
=10 min  
  
4.) Follow-up  
immediately after the intervention  
Heart rate  
Skin/core body temperature  
Oxygen saturation (blood, muscle)  
Inflammation parameters  
US  
VAS & BORG  
3 x Vertical Jumps  
3 x MVIC  
=30 min  
Oxygen saturation (blood, muscle)  
Mod. BORG & BORG  
=30 min  
  
3.) Hot water immersion  
10 min at 40°C   
Heart rate  
Skin/core body temperature  
Oxygen saturation (muscle)  
Thermal comfort and  
Temperature sensation  
=10 min  
  
4.) Follow-up  
immediately after the intervention  
Heart rate  
Skin/core body temperature  
Oxygen saturation (blood, muscle)  
Inflammation parameters  
US  
VAS & BORG  
3 x Vertical Jumps  
3 x MVIC  
=30 min  
Oxygen saturation (blood, muscle)  
Mod. BORG & BORG  
=30 min  
  
3.) Passive supine position  
10 min at room temperature  
Heart rate  
Skin/core body temperature  
Oxygen saturation (muscle)  
Thermal comfort and  
Temperature sensation  
=10 min  
  
4.) Follow-up  
immediately after the intervention  
Heart rate  
Skin/core body temperature  
Oxygen saturation (blood, muscle)  
Inflammation parameters  
US  
VAS & BORG  
3 x Vertical Jumps  
3 x MVIC  
=30 min  
Oxygen saturation (blood, muscle)  
Mod. BORG & BORG  
=30 min  
  
3.) Passive supine position  
10 min at room temperature  
Heart rate  
Skin/core body temperature  
Oxygen saturation (muscle)  
Thermal comfort and  
Temperature sensation  
=10 min  
  
4.) Follow-up  
immediately after the intervention  
Heart rate  
Skin/core body temperature  
Oxygen saturation (blood, muscle)  
Inflammation parameters  
US  
VAS & BORG  
3 x Vertical Jumps  
3 x MVIC  
=30 min  

 
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5.) Cold water immersion  
10 min at 10°C   
Heart rate  
Skin/core body temperature  
Oxygen saturation (muscle)  
Thermal comfort and thermal 
sensation  
=10 min  
  
6.-8.) Follow up  
24, 48 and 72 hours after the 
intervention 
Heart rate  
Skin/ core body temperature  
Oxygen saturation (blood, muscle)  
Inflammation parameters  
US  
VAS & BORG   
3 x Vertical Jumps  
3 x MVIC  
=30 min per follow-up  
5.) Hot water immersion  
10 min at 40°C   
Heart rate  
Skin/core body temperature  
Oxygen saturation (muscle)  
Thermal comfort and thermal 
sensation  
=10 min  
  
6.-8.) Follow up  
24, 48 and 72 hours after the 
intervention  
Heart rate  
Skin/ core body temperature  
Oxygen saturation (blood, muscle)  
Inflammation parameters  
US  
VAS & BORG   
3 x Vertical Jumps  
3 x MVIC  
=30 min per follow-up  
  
  
  
  
  
  
 
  
5.-7.) Follow up  
24, 48 and 72 hours after the 
intervention 
Heart rate  
Skin/ core body temperature  
Oxygen saturation (blood, muscle)  
Inflammation parameters  
US  
VAS & BORG   
3 x Vertical Jumps  
3 x MVIC  
=30 min per follow-up  
  
  
  
  
  
  
  
  
5.-7.) Follow up  
24, 48 and 72 hours after the 
intervention  
Heart rate  
Skin/core body temperature  
Oxygen saturation (blood, muscle)  
Inflammation parameters  
US  
VAS & BORG   
3 x Vertical Jumps  
3 x MVIC  
=30 min per follow-up  
 

 
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Baseline,recording of adverse events 
30min  
Unique  
Jump log, recording of adverse events 
30min  
Unique  
Cold water immersion, recording of adverse events 20min + 130min (3x30min) = 150min  
Unique  
Hot water immersion, recording of adverse events 
20min + 130min (3x30min) = 150min  
Unique  
Hypoxia group, recording of adverse events 
20min + 120min (3x30min) = 140min  
Unique  
Control group, recording of adverse events 
20min + 120min (3x30min) = 140min  
Unique  
Total time spent 
245min or 255min  
  
Test protocol 
Time exposure  
Visits  
Information, written consent, examination of 
inclusion/ exclusion criteria, health questionnaires, 
pregnancy test, detection of adverse events  
30min + 15min  
Unique  

 
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9.2 Assessments of outcomes  
The following data are collected during all tests described in the sub-protocols in chap. 9.1.  
9.2.1  Assessment of primary outcome   
Jump height measurement  
The jump height after exercise is determined using a jump height measuring plate designed for this 
purpose (Just Jump Plate, Probotics Inc., Huntsville, USA). The test subjects assume a standing position 
on the plate. They are allowed to start from the squatting position to measure the jump height 
(countermovement jump). The arms must be placed at the hips during the entire movement. The 
measurement moments take place directly, 24 hours, 48 hours and 72 hours after the intervention.  
Muscle activity (MVIC)  
MVIC is performed on the Cor 1 – ergometer chair for biomechanical measurements V1.0 and is given 
in kg (www.otbioelettronica.it). The conduction velocity is measured with the help of the surface 
electromyogram system EMG-USB2 from OT Bioelettronica (otbioelettronica.it), bandpass filtered 
between 10-750Hz and rectified (full-wave rectify). MVIC is measured on the Cor 1 ergometer chair in 
90° knee flexion. The raw data of muscle activity to measure conduction velocity is processed using OT 
Bioelettronica's (MISO II) software. The electrodes are placed according to the guidelines of Barbero et 
al. (2012) "Atlas of Muscle Innervation Zones". The EMG electrodes are placed on the front of the thigh 
and on the tibia. These areas must be shaved if there is too much hair. The measurement takes place 
immediately, 24 hours, 48 hours and 72 hours after the intervention. 
Muscle swelling  
Muscle swelling of the thigh is measured by ultrasound imaging (MyLabClassC, Esaote, Genoa, Italy). 
The images are analysed with the OsiriX DICOM viewer software (OsiriX, Pixmeo SARL, Switzerland). 
The measurements are taken before, immediately, 24 hours, 48 hours and 72 hours after the 
intervention.  
Oxygen saturation of the blood  
The oxygen saturation of the blood is measured with a portable pulse oximeter with a finger clip probe 
(Nonin 7500, Nonin medical B.V., Plymouth, USA). This measurement takes place during the baseline 
measurements as well as during the jump protocol.  
Oxygen saturation of the muscle  
The oxygen saturation (%) of the thigh muscles is measured using the tissue oxygenation monitor using 
near-infrared spectroscopy (moorVMS-NIRS, moor instruments, www.moor.co.uk). The measurement is 
non-invasive and takes place using near-infrared light. The sensors are fixed around the corresponding 
muscles. The oxygen saturation measurement is taken directly and 24, 48 and 72 hours after the 
intervention.  
Heart rate  
The heart rate is determined using a heart rate monitor with a chest strap (Polar T31, Polar Inc. Kempele, 
Finland). Blood pressure and heart rate are measured directly and 24, 48 and 72 hours after the 
intervention.  
Skin temperature  
Skin temperature is measured via the iButton system (www.ibuttonlink.com). The self-adhesive sensors 
transmit the information about the skin temperature wirelessly to a computer. Furthermore, the skin 
temperature is recorded using a thermal imaging camera (A655 sc series, FLIR, InfrarotTec Systems, 
Ranstadt, Germany). The skin temperature is measured directly and 24, 48 and 72 hours after the 
intervention. The iButtons are applied with a tape strip to the following areas: centre of the shoulder 
blade, neck (6th cervical vertebra), back of the hand, centre of the shin, and centre of the thigh. The 
iButtons are removed from the affected areas during the cold water bath or hot water bath and then 
reattached.  

 
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Core Body Temperature  
The 
core 
body 
temperature 
is 
determined 
via 
the 
e-Celsius® 
performance 
(https://www.bodycapmedical.com). With the help of this ingestible capsule, the core body temperature 
is continuously monitored, recorded and transmits the data wirelessly to a monitor (BodyCAP medical, 
Hérouville Saint-Clair, France). Core body temperature is measured directly and 24, 48 and 72 hours 
after the intervention.  
Inflammation parameters  
The measurement of inflammatory parameters such as creatine kinase, interleukin 6 or C-reactive 
protein (CRP) is carried out via a venous blood sample of approx. 6ml (Accutrend, Roche Diagnostic, 
Rotkreuz, Switzerland & Reflotron, Roche Diagnostic, Rotkreuz, Switzerland). The measurement is 
carried out immediately, 24 hours, 48 hours and 72 hours after the intervention by trained specialists.  
Subjective information on shortness of breath  
The subjects reported their subjective feeling of shortness of breath on a modified BORG scale (0 – 10). 
The scale will be scaled from "0" (no shortness of breath at all) to "10" (maximum breathlessness). The 
measurement takes place before the intervention.  
Subjective information on general exhaustion  
The subjects reported their subjective general feeling of exhaustion on a BORG scale (6 – 20). The scale 
will be scaled from "6" (very, very light load) to "20" (very, very strenuous load). The measurement takes 
place before the intervention.  
Subjective muscle soreness  
The test subjects reported their subjective feeling of muscle soreness on a visual analogue scale (VAS). 
The scale will be scaled from "0" (no muscle soreness present) to "10" (largest imaginable muscle 
soreness) in cm increments. The measurement moments take place directly, 24 hours, 48 hours and 72 
hours after the intervention.  
Thermal comfort and temperature sensation  
This parameter is measured using a scale. The test subjects indicate their subjective temperature 
perception on a 9-point scale from -4 (very cold) to +4 (very hot). They then rate the thermal comfort 
from 0 (pleasant) and 4 (extremely unpleasant) on a 5-point scale. These measurements are taken 
before and after the intervention.  
9.2.2  
Assessment of secondary outcomes  
None available. 
9.2.3  
Assessment of other outcomes of interest  
None available. 
9.2.4  
Assessment of safety outcomes  
No corresponding parameters are collected.  
9.2.4.1  Adverse events   
-  
9.2.4.2  Laboratory parameters  
-  
  
9.2.4.3  Vital signs  
-  

 
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9.2.5  Assessments in participants who prematurely stop the study  
There is no disadvantage for the participants if they (arbitrarily) discontinue study participation, and no 
further interventions are necessary for follow-up treatment.  
However, if participation in the study is cancelled due to an injury sustained during participation, this will 
be recorded and reported to the sponsor, the head of the research laboratory, the study director, and the 
supervisor of the study. The report is also sent to Thim van der Laan AG’s public liability insurance to 
ensure the appropriate follow-up treatment.  
The following are recorded:  
- 
Date and time of the incident  
- 
Course of the incident  
- 
Persons involved & witnesses  
- 
Study ID (issued by the CEC)  
- 
Personal details of the person concerned (if not previously recorded)  
9.3 Procedures at each visit  
9.3.1 Single measurement  
The project involves multiple visits. 
9.3.2 Multiple visits  
The project involves multiple visits with a maximum duration of 255 minutes, which are organised as 
follows:  
1. Subject information & informed consent  
The test subjects are given comprehensive information about the procedure and possible risks before 
agreeing to participate in the study. They also receive the information in written form and have the 
opportunity to ask questions. The informed consent form explains to them what their rights and 
obligations are when participating and that they may withdraw from participation at any time without 
giving reasons and without incurring any disadvantages. More detailed information can be found in 
section 2.7.  
2. Preparing the test subjects  
If the test subject is willing to participate, she is instructed to get changed in a separate room.  
First, the locations for the placement of the electrodes are marked with a skin-friendly pen (eyeliner) 
and, if necessary, individual locations of the EMG electrode placements are shaved (both were explained 
to the test subject beforehand according to a checklist). The electrodes are then attached. The 
electrodes are attached to the lower third of the anterior thigh muscle. Furthermore, the locations for 
placing the sensors for measuring skin temperature and oxygen saturation on the thigh are marked with 
a skin-friendly pencil (eyeliner). A heart rate monitor is applied to the test subject and to start the 
measurement of the core body temperature, the test subject is asked to take a capsule. It is also checked 
that no metal jewellery is worn on the body before the test subjects complete the jump protocol.  
3. Measurements  
The tests are carried out, and the data is collected in accordance with the test protocol.  
  
4. Compensation and Conclusion  
After completion of the individual measurement, the test subject is asked to change again in a separate 
room. Afterwards, she is asked how she feels. The subject is asked to report back to the laboratory at 
intervals of 24 hours, 48 hours and 72 hours to carry out the follow-up measurements. MVIC, the 

 
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maximum jump height, skin temperature, core body temperature, heart rate, inflammation parameters, 
muscle swelling and oxygen saturation in the thigh are measured again. Furthermore, subjective muscle 
soreness and general exhaustion are recorded. After completion of the measurements, the test subject 
receives the compensation to which they are entitled in accordance with the information in the 
advertisement:  
Flat rate CHF 50 after completion of the measurements (measurement time: after 72 hours).   
  
  
 

 
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10. REGULATORY ASPECTS AND SAFETY   
Other clinical trial with a medical device in the risk category Cat. A (chap. 4)  
No medication is administered to the test subjects and no tissue samples are taken. Only minimally 
invasive methods are used.  
The current regulations of the Canton of Graubünden and those of the FOPH for protection against the 
coronavirus will be taken into account and implemented when conducting the study.  
 
10.1 Local regulations / Declaration of Helsinki  
This study is conducted in compliance with the protocol, the current version of the Declaration of Helsinki, 
the ICH-GCP, the HRA as well as other locally relevant legal and regulatory requirements.  
10.2 (Serious) Adverse Events and notification of safety and protective 
measures  
An Adverse Event (AE) is any untoward medical occurrence in a patient or a clinical investigation subject, 
which does not necessarily have a causal relationship with the trial procedure. An AE can therefore be 
any unfavourable or unintended finding, symptom, or disease temporally associated with a trial 
procedure, whether or not related to it.  
  
A Serious Adverse Event (SAE) (ClinO, Art. 63) is any untoward medical occurrence that  
-Results in death or is life-threatening,  
-Requires in-patient hospitalisation or prolongation of existing hospitalisation,  
-Results in persistent or significant disability or incapacity, or  
-Causes a congenital anomaly or birth defect   
  
Both Investigator and Sponsor-Investigator make a causality assessment of the event to the trial 
intervention, (see table below based on the terms given in ICH E2A guidelines). Any event assessed as 
possibly, probably or definitely related is classified as related to the trial intervention.  
  
Relationship  
Description  
Definitely  
Temporal relationship  
Improvement after dechallenge*  
Recurrence after rechallenge  
(or other proof of drug cause)  
Probably  
Temporal relationship  
Improvement after dechallenge  
No other cause evident  
Possibly  
Temporal relationship  
Other cause possible  
Unlikely  
Any assessable reaction that does not fulfil the above conditions  
Not related  
Causal relationship can be ruled out  
*Improvement after dechallenge only taken into consideration, if applicable to reaction  

 
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Both Investigator and Sponsor-Investigator make a severity assessment of the event as mild, moderate 
or severe. Mild means the complication is tolerable, moderate means it interferes with daily activities 
and severe means it renders daily activities impossible.  
  
Reporting of SAEs (see ClinO, Art. 63)  
All SAEs are documented and reported immediately (within a maximum of 24 hours) to the Sponsor-
Investigator of the study.  
If it cannot be excluded that the SAE occurring in Switzerland is attributable to the intervention under 
investigation, the Investigator reports it to the Ethics Committee via BASEC within 15 days.  
  
Notification of safety and protective measures (see ClinO, Art 62, b)  
If immediate safety and protective measures have to be taken during the conduct of the study, the 
investigator notifies the Ethics committee of these measures, and of the circumstances necessitating 
them, within 7 days.  
10.3 (Periodic) safety reporting  
An annual safety report (ASR/DSUR) is submitted once a year to the local Ethics Committee by the 
Investigator (ClinO, Art. 43 para).  
  
10.4 Amendments  
Substantial changes to the study setup and study organization, the protocol and relevant study 
documents are submitted to the Ethics Committee for approval before implementation. Under emergency 
circumstances, deviations from the protocol to protect the rights, safety and well-being of human subjects 
may proceed without prior approval of the Ethics Committee. Such deviations shall be documented and 
reported to the Ethics Committee as soon as possible.  
A list of all non-substantial amendments will be submitted once a year to the competent EC together 
with the ASR.  
  
10.5 (Premature) termination of study  
The Sponsor-Investigator may terminate the study prematurely according to certain circumstances, e.g.  
- 
Ethical concerns,  
- 
Insufficient participant recruitment,  
- 
When the safety of the participants is doubtful or at risk (e.g. when the benefit-risk 
assessment is no longer positive),  
- 
Alterations in accepted clinical practice that make the continuation of the study unwise, or 
- 
Early evidence of harm or benefit of the experimental intervention  
  
Upon regular study termination, the Ethics Committee is notified via BASEC within 90 days (ClinO, Art. 
38).   
Upon premature study termination or study interruption, the Ethics Committee is notified via BASEC 
within 15 days (ClinO, Art. 38).  
  
  

 
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10.6 Insurance  
The notification is also sent to the business liability insurance (Basler Versicherung) of Thim van der 
Laan AG in Landquart. Proof of this insurance policy will also be submitted.  
  
  
 

 
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11. STATISTICAL METHODS  
11.1 Hypothesis  
Jump height (cm)  
H0  
The jump height is not increased by the hot water immersion compared to the cold water 
immersion, hypoxia group and passive control group during a 72-hour recovery phase.  
H1  
MVIC (kg)  
The jump height is increased by the hot water immersion compared to the cold water 
immersion, hypoxia group and passive control group during 72 hours.  
H0  
MVIC performance is not increased by hot water immersion compared to cold water 
immersion, hypoxia group, and passive control group during a 72-hour recovery period.  
H1  
The MVIC efficiency is increased by hot water immersion compared to cold water 
immersion, hypoxia group and passive control group during 72 hours.  
  
Muscle swelling (mm)  
H0 Muscle swelling is not increased by hot water immersion compared to cold water immersion, 
hypoxia group, and passive control group during a 72-hour recovery period.  
H1 Muscle swelling is increased by hot water immersion compared to cold water immersion, 
hypoxia group and passive control group for 72 hours.  
  
Blood oxygen saturation (%)  
H0 Blood oxygen saturation is not increased by hot water immersion compared to cold water 
immersion, hypoxia group and passive control group during a 72-hour recovery period.  
H1 The oxygen saturation of the blood is increased by the hot water immersion compared to the 
cold water immersion, hypoxia group and passive control group during 72 hours.  
  
Oxygen Saturation Muscle (%)  
H0 Oxygen saturation of the thigh muscle is not increased by hot water immersion compared to 
cold water immersion, hypoxia group and passive control group during a 72-hour 
recovery period.  
H1 The oxygen saturation of the thigh muscle is increased by hot water immersion compared to 
cold water immersion, hypoxia group and passive control group during 72 hours.  
  
Heart rate (b/min)  
H0 The heart rate is not increased by the hot water immersion compared to the cold water 
immersion, hypoxia group and passive control group during a 72-hours of recovery.  
H1 Heart rate is increased by hot water immersion compared to cold water immersion, hypoxia 
group and passive control group during 72 hours.  
 
  
 

 
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Skin temperature (°C)  
H0 Skin temperature is not increased by hot water immersion compared to cold water 
immersion, hypoxia group and passive control group during a 72-hour recovery period.  
H1 Skin temperature is increased by hot water immersion compared to cold water immersion, 
hypoxia group and passive control group during 72 hours.  
  
Core Body Temperature (°C)  
H0 Core body temperature is not increased by hot water immersion compared to cold water 
immersion, hypoxia group, and passive control group during a 72-hour recovery period.  
H1 Core body temperature is increased by hot water immersion compared to cold water 
immersion, hypoxia group and passive control group during 72 hours.  
  
Inflammation parameters (CRP, IL6, CK)  
H0  
Inflammation levels are not increased by hot water immersion compared to cold water 
immersion, hypoxia group, and passive control group during a 72-hour recovery period.  
H1  
The inflammation rates are increased by hot water immersion compared to cold water 
immersion, hypoxia group and passive control group during 72 hours.  
  
Subjective information on shortness of breath (mod. BORG)  
H0 Subjective information on shortness of breath is not increased by hot water immersion 
compared to cold water immersion, hypoxia group and passive control group during a 
72-hour recovery period.  
H1 The subjective information on shortness of breath is increased by hot water immersion 
compared to cold water immersion, hypoxia group and passive control group during 72 
hours.  
  
Subjective data on general exhaustion (BORG)  
H0 The subjective data on general fatigue are not increased by the hot water immersion 
compared to the cold water immersion, hypoxia group and passive control group during 
a 72-hour recovery period.  
H1 The subjective data on general fatigue are increased by the hot water immersion compared 
to the cold water immersion, hypoxia group and passive control group during 72 hours.  
  
  
Subjective muscle soreness (VAS)  
H0 Subjective muscle soreness is not increased by hot water immersion compared to cold water 
immersion, hypoxia group, and passive control group during a 72-hour recovery period.  
H1 Subjective muscle soreness is increased by hot water immersion compared to cold water 
immersion, hypoxia group and passive control group during 72 hours.  
  
 
 
 

 
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Thermal comfort and temperature perception  
H0  
Thermal comfort and temperature perception are not increased by hot water immersion 
compared to cold water immersion, hypoxia group and passive control group during a 
72-hour recovery period.  
H1  
Thermal comfort and temperature perception are increased by hot water immersion 
compared to cold water immersion, hypoxia group and passive control group during 72 
hours.  
  
A 2-factor analysis is carried out.  
Factor 1:  
Intervention (cold water immersion vs. hot water immersion vs. hypoxia group vs.  
Passive Control Intervention)  
Factor 2:  
Time (Baseline, 0, 24 hours, 48 hours, 72 hours)  
11.2 Determination of Sample Size   
Based on a study with a comparable setting (Ferreira-Junior et al. 2014, Fonda et al. 2013, Hausswirth 
et al. 2011) and outcome, the power analysis was calculated using the G*Power App (Düsseldorf, North 
Rhine-Westphalia, DEU), whereby a minimum number of 33 subjects was considered necessary to 
ensure the statistical power (0.80) to detect a parameter difference at the 5% significance level. Taking 
into account a possible loss of 20% of the data sets (due to drop-out or incomplete data sets), the 
minimum sample size is 40 participants. The following figure shows the G-Power calculation that was 
used to determine the sample size.  
  
  
Figure: Sample Size Calculation  
  

 
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11.3 Statistical criteria of termination of trial   
Only data from subjects who have completed the entire protocol will be included in the study. This 
ensures that all data has been collected under the same conditions and thus remains homogeneous 
and comparable.  
11.4 Planned Analyses  
11.4.1 Datasets to be analysed, analysis populations  
Only complete data sets will be included in the study. Data that contains only part of the protocol is not 
included in the analysis. No new subject is being sought to replace the missing data.  
11.4.2 Primary Analysis  
The statistical data analysis will be carried out by Dr. Erich Hohenauer once the data collection for the 
entire project has been completed.  
Repeated measures analysis of variance (MANOVA)  
2 factors:  
Factor 1:  
Intervention (cold water immersion vs. hot water immersion vs. hypoxia group vs. 
passive control intervention)  
Factor 2:  
Time (Baseline, 0, 24 hours, 48 hours, 72 hours)  
  
The significance level is set at P < 0.05, and the statistical data analysis is carried out with SPSS 27.  
  
11.4.3 Secondary Analyses  
Not Available.  
11.4.4 Interim analyses  
The data is processed once the respective sub-protocol has been completed. Thus, the data analysis 
for the entire study takes place in stages. No additional interim analyses are planned.  
11.4.5 Safety analysis  
-  
11.4.6 Deviation(s) from the original statistical plan   
Deviations from the planned statistical analysis are recorded and justified and reported to the CEC in 
the annual report.  
11.5 Handling of missing data and drop-outs   
If a test subject does not complete the experiment, any data that has already been collected is retained, 
but is not further incorporated into the final data analysis.   
 

 
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12. QUALITY ASSURANCE AND CONTROL  
12.1 Data handling and record keeping / archiving   
12.1.1 Case Report Forms   
Data protection and confidentiality are guaranteed, and no personal data is presented or published. The 
signed consent form, as well as the completed questionnaire with the other personal details and 
demographic and medical personal data, will be kept in the original as a study document in a locked 
filing cabinet. The identity of the subjects will be coded in accordance with the coding accepted by 
swissethics for a person participating in a research project. Only a person's year of birth (YYYY) is 
documented along with a coding number in the CRF.  
The project leader is responsible for the secure storage of the key for the data encrypted as part of the 
clinical trial or research project. Direct access to personal data is only permitted to authorised persons 
of the CEC.  
12.1.2 Specification of source documents   
The data collected in writing is recorded in the form listed in the enclosures and are labelled as study 
data. They are therefore subject to data protection and are stored in accordance with the information 
described in section 12.1.1.  
12.1.3 Record keeping / archiving   
The data collected is stored for 10 years. Data protection will continue to be guaranteed.  
12.2 Data management  
12.2.1 Data Management System  
The raw data of muscle activity is processed using OT Bioelettronica's (MISO II) software. The oxygen 
measurement data is acquired with the research software "moorFLPI-2 full-field laser Perfusion Imager 
V1.1". The jump height is determined with a jump height measuring plate designed for this purpose (Just 
Jump Plate, Probotics Inc., Huntsville, USA). The data from the thermal imaging camera is processed 
with the "Flir Research IR max" software. The inflammation parameters are recorded with the Reflotron 
(Roche Diagnostic, Rotkreuz, Switzerland) and transferred to a data sheet. Dyspnea and stress 
assessment are recorded in writing with a questionnaire. The subjective sensation parameters regarding 
thermal comfort and temperature perception are asked verbally and the answers are transferred by hand 
to the raw data sheet. Excel is used for further data analysis. Windows® Excel will also be used for data 
pooling and for the graphical visualisation of the final data. The skin temperature is measured via the 
iButton system and stored on the PC using the software provided (iButton MMT). To assess muscle 
swelling, the MyLabClassC ultrasound is used (Esaote, Genoa, Italy). The images are then analysed 
using the OsiriX DICOM viewer software (OsiriX, Pixmeo SARL, Switzerland).Blood oxygen saturation 
is measured with a portable pulse oximeter with finger clip probe (Nonin 7500, Nonin medical B.V., 
Plymouth, USA) and transferred directly to a Windows® Excel template. The data from the core body 
temperature measurement is transmitted wirelessly to a monitor (BodyCAP medical, Hérouville Saint-
Clair, France) and recorded.  
All data is processed on the central research computer. This research computer is located in Landquart 
(research laboratory) at all times. Only the principal investigator and the investigators (listed in Chapter 
1) know the password to unlock this computer. All digital documents are write-protected by a password. 
Only the study director and the examiners know the passwords of the digital documents. The digital 
documents are given a version number. Any changes made to the digital documents are saved as a new 
version number. In addition, all versions will be printed out and signed by the study director. The printed 
documents are stored in a separate, lockable filing cabinet. This filing cabinet also contains the password 

 
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combinations for decrypting the computer and editing the documents. Only the study director has the 
key to this filing cabinet.  
12.2.2 Data security, access and back-up   
The data is encrypted and treated confidentially; access to the personal data is not permitted to third 
parties. The digital data collected is stored solely on the institute's own computers and is not passed on 
to any external persons or transferred to other computers. Access to the computers of the research 
laboratory at the "University of Applied Sciences and Arts of Southern Switzerland" is restricted to the 
study director and the investigators (listed in Chapter 1), as well as persons authorised by the CEC.  
12.2.3 Analysis and archiving  
After collection, the data is encrypted and stored on another external hard drive for further backup. This 
is stored in a locked filing cabinet to ensure data protection.  
12.2.4 Electronic and central data validation   
Immediately after data collection, the quality of the data is checked and verified with the help of the visual 
representation.  
12.3 Monitoring   
The data collected can be viewed by authorised persons at any time (see chap. 12.2.2)  
The will be monitored by the following person:  
Prof. Peter Clarys, PhD  
Vrije Universiteit Brussels   
Faculty of Physical Therapy  
Pleinlaan 2, 1050 Brussels 
peter.clarys@vub.ac.be  
  
12.4 Audits and Inspections   
A report on the current status of the study is submitted orally to the study supervisor (Prof. Dr. Peter 
Clarys) on a monthly basis. This also includes demonstrating and presenting results and statistical 
analyses.   
An annual report on the course of the study will be submitted to the CEC. Authorised staff of the CEC 
have access to the data forms and the digital data on the institute's own computers at all times.  
Data protection is guaranteed at all times.   
12.5 Confidentiality, Data Protection   
The examiners ensure that the privacy of the participant is guaranteed. In particular, data protection and 
confidentiality are guaranteed and no personal data is presented or published. The signed declaration 
of consent, as well as the completed questionnaire with the other personal details, are kept in the original 
as a study document in a locked filing cabinet.  
The data is encrypted and treated confidentially; access to the personal data is not permitted to third 
parties. The digital data collected is stored solely on the institute's own computers and is not passed on 
to third parties or transferred to other computers.  
Direct access to the personal data is only allowed to authorised CEC personnel.  

 
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12.6 Storage of biological material and related health data   
The blood samples are handled confidentially. After they have been analysed, they are 
destroyed in accordance with the applicable hygiene regulations and in compliance with 
anonymisation.   
  
  
 

 
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13. PUBLICATION AND DISSEMINATION POLICY   
The examiners ensure that the privacy of the participant is guaranteed. In particular, data protection and 
confidentiality of the data are guaranteed, and no personal data will be presented or published nor 
passed on to outsiders and unauthorised persons.  
  
  
 

 
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14. FUNDING AND SUPPORT   
14.1 Funding   
The study is funded by the University of Applied Sciences and Arts of Southern Switzerland, 
Physiotherapy Graubünden. The investigators are employed by this institute and are remunerated for 
their work on this study in accordance with their employment contracts. No further financial support is 
required.  
14.2 Other Support   
-  
15. INSURANCE   
Thim van der Laan AG in Landquart, where the study is being conducted, is covered by public liability 
insurance with Basler Versicherung.  
  
  
 

 
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16. REFERENCES   
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Ando, S., Hatamoto, Y., Sudo, M., Kiyonaga, A., Tanaka, H., & Higaki, Y. (2013). The effects of exercise 
under hypoxia on cognitive function. PLoS One, 8(5), e63630. doi:10.1371/journal.pone.0063630  
  
Ascensao, A., et al., Effects of cold water immersion on the recovery of physical performance and muscle 
damage following a one-off soccer match. J Sports Sci, 2011. 29(3): p. 217-25.  
  
Bailey, D.M., et al., Influence of cold-water immersion on indices of muscle damage following prolonged 
intermittent shuttle running. J Sports Sci, 2007. 25(11): p. 1163-70.  
  
Banfi, G., et al., Whole-body cryotherapy in athletes. Sports Med, 2010. 40(6): p. 509-17.  
  
Barbero, M., Atlas of Muscle Innervation Zones – understanding surface electromyography and its 
applications. Springer, 2012. ISBN: 8847024625.  
  
Bastos, F.N., et al., Effects of cold water immersion and active recovery on post-exercise heart rate 
variability. Int J Sports Med, 2012. 33(11): p. 873-9.  
  
Bieuzen, F., et al. "Contrast water therapy and exercise induced muscle damage: a systematic review 
and meta-analysis."  PLoS One 8 (4):e62356. doi: 10.1371/journal.pone.0062356.  
  
Bleakley, C., et al., Cold-water immersion (cryotherapy) for preventing and treating muscle soreness 
after exercise. Cochrane Database Syst Rev, 2012. 2: p. CD008262.  
  
Chang, Y. K., Labban, J. D., Gapin, J. I., & Etnier, J. L. (2012). The effects of acute exercise on cognitive 
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Costello JT, Baker PR, Minett GM, Bieuzen F, Stewart IB, Bleakley C. Whole-body cryotherapy (extreme 
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Costello JT, Bieuzen F, Bleakley CM, Where are all the female participants in Sports and Exercise 
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Costello JT, Culligan K, Selfe J, Donnely AE, Muscle skin and core temperature after -110°C cold air and 
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Sports Med, 2007. 28(12): p. 994-8.  

 
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Crystal, N.J., et al., Effect of cryotherapy on muscle recovery and inflammation following a bout of 
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Delextrat, A., et al., Effects of sports massage and intermittent cold-water immersion on recovery from 
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De Pauw, K., et al., Effect of recovery interventions on cycling performance and pacing strategy in the 
heat. Int J Sports Physiol Perform, 2014. 9(2): p. 240-8.  
  
Elias, G.P., et al., Effects of water immersion on posttraining recovery in Australian footballers. Int J 
Sports Physiol Perform, 2012. 7(4): p. 357-66.  
  
Eston, R. and D. Peters, Effects of cold water immersion on the symptoms of exercise-induced muscle 
damage. J Sports Sci, 1999. 17(3): p. 231-8.  
  
Ferreira-Junior, JB et al., Effects of a single whole body cryotherapy (-110°C) bout on neuromuscular 
percormance of the elbow flexors during isokinetic exercise, Int J Sports Med. 2014 Dec; 35(14):1179- 
83.  
  
Ferreira-Junior, JB et al., Effects of Partial-body Cryotherapy (-110°C) on Muslce Recovery between 
High-intensity Exercise Bouts, Int J Sports Med. 2014 Dec; 35(14):1155-60.  
  
Ferreira-Junior, JB et al., One session of partial-body cryotherapy (-110°C) improves muscle damage 
recovery, Scand J Med Sci Sports. 2015 Oct; 25(5):E524-30.  
  
Fonda, B., et al, Effects of whole-body cryotherapy on recovery after hamstrings damaging exercise_a 
crossover study, Scand J Med Sci Sports. 2013 Oct; 23(5):E270-8.  
  
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17. APPENDICES  
1. Subject information, informed consent & demographic subject data (Questionnaire)  
  
2. Subject recruitment (advertisements, checklist for initial contact)  
  
3. Data collection sheet measurements (Screening Test and Measurement Data Sheet)  
  
4. Protocol synopsis  
  
5. Employee list 
  
6. CVs of all examiners