The 10/7 HIIT Shock Cycle Study: Effectiveness of 10 HIIT Sessions in 7 Days

Study Overview
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Brief Summary
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A randomized, controlled trial to evaluate the effects of two versions of 10 high intensity interval trainings (HIIT) within a 7-day shock microcycle on endurance performance, well-being, health, stress and recovery in trained athletes.

Detailed Description
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Thirty-six trained endurance athletes will be recruited and randomly assigned to either a high volume (HIIT-HV) group, a low volume (HIIT-LV) group, or a control group. All participants will be monitored before (9 days), during (7 days), and after (14 days) a 7-day training intervention, for 30 days. Participants in both intervention groups will complete 10 HIIT sessions within the period of 7 days, with an additional 30 minutes of low-intensity training exclusively in HIIT-HV. HIIT sessions consist of aerobic HIIT, i.e., 5x4min at 90-95% of maximal heart rate interspersed by 2.5 min active recovery periods. To determine the effects of the intervention, performance diagnostics, and a 5 kilometer time trial will be conducted before and after the intervention. In addition, participants are closely monitored for general health, stress, fatigue, recovery, neuromuscular performance, executive functions and sleep.

Official Title
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The 10/7 HIIT Shock Cycle Study: The Effects of a 7-Day High-Intensity-Interval Training Shock Microcycle on Endurance Performance, Well-Being, Stress and Recovery in Endurance Trained Athletes - Randomized Controlled Trial

Conditions
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Healthy, Athlete, Performance

Intervention / Treatment
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* Other: Exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Female or male aged 18-45 years Proof of physical fitness (e.g. sports medical examination required) for measurements with higher intensities (e.g. endurance tests, competition simulation) Competition experience at the national or international level in an endurance sport VO2max ≥50ml/kg/min for females; ≥55 ml/kg/min for males or a 5-kilometer (km) time trial performance of ≤ 20:00 min (female), or ≤ 18:30 min (male) Exclusion Criteria: Systemic disease or other known pathology in the organs: heart, lungs, kidney, stomach, spleen, liver, gall bladder, and intestines. Evidence of pulmonary disease: forced expiratory volume in one second/forced expiratory volume < 70% with/without symptoms (cough, sputum) or other evidence of pulmonologic disease. Diabetes II. Neurological or psychological disease of any kind. Currently undergoing medical or psycho-therapeutic treatment. Health condition that does not allow regular participation in the training forms (e.g. acute illnesses such as fever or other flu-like infections within the last 7 days before the start of the study), orthopedic diseases, injuries to the muscular, bone, joint or tendon apparatus within the last three months. Alcohol or drug abuse. Already high training volume with high intensity training (more than 2 weekly training sessions of high-intensity training)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Participants are randomly assigned in either one of 2 intervention groups or a control group (ratio 1:1:1).
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: HIIT-HV<br>HIIT-HV - high intensity interval training high volume Participants complete a total of 10 HIIT sessions over a 7-day period consisting of 5 x 4-minute intervals at an intensity of 90-95% of their individual maximum heart rate (HRmax), interspersed with a 2.5-minute active recovery period. Each training session is followed by 30 minutes of low-intensity training (total of 300 minutes of additional low-intensity training during this period). | Other: Exercise<br>* high-intensity interval training sessions<br>|
| Experimental: HIIT-LV<br>HIIT- LV - high intensity interval training low volume Participants complete a total of 10 HIIT sessions over a 7-day period consisting of 5 x 4-minute intervals at an intensity of 90-95% of their individual maximum heart rate (HRmax), interspersed with a 2.5-minute active recovery period. | Other: Exercise<br>* high-intensity interval training sessions<br>|
| No Intervention: Control group<br>Participants continue with their regular training program. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Endurance performance I | Change of maximal oxygen uptake (VO2max in ml/min/kg) compared to baseline and group | 10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) | 
| Endurance performance II | Change of peak performance (Ppeak in Watt) compared to baseline and group | 10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) | 
| Endurance performance III | Change of 5 kilometer time trial performance (in sec) compared to baseline and group | 20 to 22 days (the assessment is conducted once before, and once after the intervention) | 
| Endurance performance IV | Change of lactate threshold (in km/h) compared to baseline and group | 10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) | 
| Endurance performance V | Change of ventilatory thresholds (in km/h) compared to baseline and group | 10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) | 
| Endurance performance VI | Change of running economy (in ml/min/kg) compared to baseline and group | 10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of questionnaire scores - well-being | Change of questionnaire scores compared to baseline and group as determined by a Visual-Analogue-Scale (from 0-100 millimeters). Higher scores indicate poorer well-being. | 30 days (questionnaires will be given to participants several times before, during, and after the intervention.) | 
| Change of questionnaire scores - muscular fatigue | Change of questionnaire scores compared to baseline and group as determined by a Visual-Analogue-Scale (from 0-100 millimeters). Higher scores indicate higher degree of fatigue. | 30 days (questionnaires will be given to participants several times before, during, and after the intervention.) | 
| Change of questionnaire scores - vitality | Change of questionnaire scores compared to baseline and group as determined by a Likert-Scale (from 0-10). Higher scores indicate higher vitality. | 30 days (questionnaires will be given to participants several times before, during, and after the intervention.) | 
| Change of questionnaire scores - rate of fatigue | Change of questionnaire scores compared to baseline and group as determined by a Likert-Scale (from 0-10). Higher scores indicate higher degree of fatigue. | 30 days (questionnaires will be given to participants several times before, during, and after the intervention.) | 
| Change of questionnaire scores - sleep quality | Change of questionnaire scores compared to baseline and group as determined by a Likert-Scale (from 1-7). Higher scores indicate poorer sleep. | 30 days (questionnaires will be given to participants several times before, during, and after the intervention.) | 
| Change of blood count | Change of blood count concentrations compared to baseline and group | 30 days (blood is drawn from participants several times before, during, and after the intervention.) | 
| Change of cell-free DNA | Change of cell-free DNA concentrations compared to baseline and group | 30 days (blood is drawn from participants several times before, during, and after the intervention.) | 
| Change of creatine kinase | Change of creatine kinase concentrations compared to baseline and group | 30 days (blood is drawn from participants several times before, during, and after the intervention.) | 
| Change of urea | Change of urea concentrations compared to baseline and group | 30 days (blood is drawn from participants several times before, during, and after the intervention.) | 
| Change of blood lactate | Change of blood lactate concentrations compared to baseline and group | 30 days (blood is drawn from participants several times before, during, and after the intervention.) | 
| Change of cytokines | Change of cytokine concentrations compared to baseline and group | 30 days (blood is drawn from participants several times before, during, and after the intervention.) | 
| Change of miRNA | Change of miRNA compared to baseline and group | 30 days (blood is drawn from participants several times before, during, and after the intervention.) | 
| Change of neuromuscular performance | Change of neuromuscular performance (counter movement jump height in cm) measured on a contact plate (AMTI, Watertown, USA) compared to baseline and group | 30 days (neuromuscular performance is assessed several times before, during, and after the intervention) | 
| Change of body weight | Change of body weight in kg compared to baseline and group | 10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) | 
| Change of fat free mass | Change of fat free mass in kg compared to baseline and group | 10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) | 
| Change of fat mass | Change of fat mass in kg compared to baseline and group | 10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) | 
| Change of forced expiratory volume | Change of forced expiratory volume in liters compared to baseline and group | 10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) | 
| Change of power output during exercise | Change of power output in Watt (as determined via Stryd, Boulder, USA) during the intervention compared to baseline and group | 7 days | 
| Change of sleep quality I - GPS watch | Change of sleep quality compared to baseline and group as determined by a GPS (Global Positioning System) watch | 30 days (sleep is assessed several times before, during, and after the intervention) | 
| Change of sleep quality II - ABIOS App | Change of sleep quality compared to baseline and group as determined by the ABIOS (Algorithmik Biodata System) application | 30 days (sleep is assessed several times before, during, and after the intervention) | 
| Correlations between sleep quality devices | To determine the correlations between different sleep monitoring devices, i.e. the GPS watch (see outcome 27), the ABIOS system (see outcome 28) and the sleep quality questionnaire (see outcome 11) | 30 days | 
| Change of parameters recorded by an electrocardiogram - mean heart rate | Change of mean heart rate compared to baseline and group | 30 days (an electrocardiogram is written several times before, during, and after the intervention) | 
| Change of parameters recorded by an electrocardiogram - heart rate variability | Change of heart rate variability (root mean sum of squared distance in ms) compared to baseline and group | 30 days (an electrocardiogram is written several times before, during, and after the intervention) | 
| Change of executive functions - Eriksen flanker task | Change of executive functions compared to baseline and group. This is recorded through a modified Eriksen flanker task consisting of 108 images showing five white arrows on a black screen. | 30 days (executive functions are tested several times before, during, and after the intervention) | 
| Change of executive functions - 2 back task | Change of executive functions compared to baseline and group. This is assessed through a 2-back task showing dots on a dice, numbers and geometrical figures. | 30 days (executive functions are tested several times before, during, and after the intervention) | 
| Cardiac ultrasound | Description of an athlete cohort regarding cardiac chamber volume (in ml, determined via EPIQ CVX, X5-1, Philips Healthcare, Andover, MA, USA) | 1 day (this outcome will be determined once before study start) | 
| Adherence to training program | Adherence to the HIIT training programs (determined as the ratio of training sessions performed to prescribed training sessions). This is determined by the researchers by checking the training data of the athletes. For example, if 9 out of 10 sessions were performed, this means 90% adherence. | 7 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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High-intensity interval training, Microcycle, Endurance training, Load monitoring, Athlete performance, HIT training, Block training, HIT block, Polarized training