Effects of Remote Limb Ischemic Conditioning to Enhance Performance, Cognitive-motor Learning and Muscle Strength in Healthy Young Adults
Phase: PHASE1
Conditions: Healthy, Young Adults
Sponsor: Washington University School of Medicine

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Remote limb ischemic conditioning to enhance learning and muscle strength in healthy, young adults 
 
NCT# 03512028 
July 14, 2017 
 

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Remote Limb Ischemic Conditioning to Enhance Performance, Learning 
And Muscle Strength 
 
Study Objectives 
The objective of this research study is to determine if remote limb ischemic 
conditioning (RLIC) can enhance learning of an ecologically valid, complex 
cognitive-motor (driving) task and increase skeletal muscle strength in 
neurologically intact young adults. 
Background & 
Rationale 
Ischemic conditioning is an endogenous phenomenon in which exposing a 
target organ or tissue to one or more brief episodes of ischemia results in 
protection of that organ against subsequent ischemia (Gidday, 2006). The 
effects of ischemic conditioning are not confined within an organ but can be 
can be transferred from one organ to another, a technique called remote 
ischemic conditioning (Saxena et al., 2010). A clinically feasible method for 
this is remote limb ischemic conditioning (RLIC), where episodes of 
ischemia and perfusion are induced with a blood pressure cuff placed on 
the arm (Kharbanda et al., 2009). 
 
In humans, the cardioprotective effects of RLIC have been demonstrated 
(Hausenloy et al., 2007; Botker et al., 2010). For example, applying an 
inflated blood pressure cuff to the upper or lower limb has shown efficacy 
for protection in people undergoing cardiac surgeries (Hausenloy et al., 
2007; Meng et al., 2012), elective surgery to repair abdominal aortic 
aneurysm (Ali, Callaghan et al. 2007), experiencing myocardial infarction 
(Botker et al., 2010), and with symptomatic intracranial arterial stenosis 
(Meng, Asmaro et al. 2012). Although the cardioprotective effects of RLIC 
have been well established, the neuroprotective effects are just beginning 
to be evaluated (Meng et al., 2012). Moreover, the effects of RLIC on 
skeletal muscle is largely unknown. Only a single study so far has shown 
that RLIC decreases depletion of ATPs, decreases lactate accumulation 
and increases myeloperoxidase, which helps in reducing inflammation and 
apoptosis in skeletal muscles of rats (Addison et al., 2003). 
 
The proposed study is a part of larger study that is investigating if the 
effects of RLIC might extend beyond cardio- and neuroprotection and into 
plasticity, learning and recovery. The preliminary results of the proof-of-
concept study from our lab has shown that RLIC robustly facilitates motor 
learning and retention in young, neurologically intact adults (Cherry-Allen et 
al., 2015). However, these learning effects have been seen in a lab 
controlled motor task. Hence, the next step is to investigate if RLIC can 
enhance performance of real world, ecologically valid complex cognitive-
motor task such as driving in a simulated environment and increase 
skeletal muscle strength in healthy young adults.  
 
This study is important because if eventually effective, RLIC could have 
profound effect on the rehabilitation and recovery of cognitive-motor function 
and muscle strength in people with stroke. It is important to first start this 
translational investigation in neurologically intact people in order to 
determine optimal protocols for people with stroke. 
Study Design 
Between groups repeated measures design.  

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Groups 
Group 1: Neurologically Intact Subjects + 5 cycles of RLIC 
Group 2: Neurologically Intact Subjects + 5 cycles of sham conditioning 
 
Subjects who qualify and consent will be randomly assigned to either group 
1 or 2.  Allocation will be concealed from those responsible for assessing 
participants for eligibility and entry into the study. 
Number of 
Subjects & Power 
Analysis 
Based on our pilot data for the balance task training, we will need 20 
participants in each group (total 40) to achieve atleast 80% power to detect 
mean differences of 3 seconds of change scores (posttest - pretest) 
between two treatment groups (RLIC vs. Sham) based on a two-sample t-
test at a significance level of 0.05. The standard deviations for change 
scores are assumed to be 2.5 seconds and 1.9 seconds for the RLIC and 
sham groups, respectively. We request permission to enroll 55 subjects 
total to allow for screen failures and subjects those who do not complete all 
study visits. 
 
Based off of the earlier study on strength training (Christie and Kamen, 
2010), 20 participants in each group (40 total) will give 98% power to detect 
mean difference of 17 % change in the muscle strength (posttest – pretest) 
after 2-weeks strength training based on a two-sample t-test at a 
significance level of 0.05. The standard deviations for change scores are 
assumed to be 10.81 lbs and 12.2 lbs for pre- and post-strength training 
respectively.  
 
 
Inclusion & 
Exclusion Criteria 
Inclusion Criteria:  
1) Healthy adults between the age of 18 and 40 years  
 
Exclusion Criteria:  
1) History of neurological condition (i.e. stroke, Alzheimer's disease, 
Parkinson's disease), ADD, ADHD, depression, bipolar disorder, balance 
impairment, or vestibular disorder  
2) History of motion sickness, moderate to severe motion sickness on 
nausea or oculo-motor components of Simulator sickness questionnaire 
(Appendix 1) (Kennedy et al., 1993), inability to ride a car, boat, train or 
airplane, and impaired vision, and visual acuity below state guidelines for 
driving  
3) Recent wrist, hand or forearm injury that would prevent ability to lift 
weights 
4) History of lower extremity condition, injury, or surgery which could 
compromise performance on motor training task  
5) Any extremity soft tissue, orthopedic, or vascular injury (i.e. peripheral 
vascular disease) which may contraindicate RLIC  
6) Any cognitive, sensory, or communication problem that would prevent 
completion of the study  
7) History of sleep apnea 
8) Current intensive weight lifting or interval training exercise  
9) Current substance abuse or dependence  
10) Unwillingness to travel for all study visits  
 

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RLIC Treatment 
Parameters 
 
Remote limb ischemic conditioning will be achieved via blood pressure cuff 
inflation to 20 mmHg above systolic blood pressure on the non-dominant, 
upper extremity (Cherry-Allen et al.; 2017). Sham conditioning will be 
achieved via blood pressure cuff inflation to 10 mmHg under diastolic blood 
pressure on the non-dominant, upper extremity. Conditioning will involve 5 
cycles of 5 minutes blood pressure cuff inflation followed by alternating 5 
minutes of cuff deflation. Subjects will be blinded to their group assignment 
(RLIC or sham conditioning). Conditioning requires 45 minutes.  
 
Behavioral 
Training  
Three tasks will be used for behavioral training on visit 3-8.  
 
1) Driving task (15-20 minutes) 
2) Strengthening task (20-30 minutes) 
3) Balance training task (15 minutes; rest breaks as needed) 
 
Driving task: The driving task requires the subject to drive in a simulated 
environment of STISIM M300WS (Systems Technology, Inc.), which 
presents a realistic driving experience through controlled, complex tasks 
related to vehicle dynamics, natural pedal and steering wheel controls, and 
a wide field of view display. Participants are asked to drive through 
increasingly complex scenario over mixed roadways (complex urban, 
suburban, rural, and construction zone). Hazards, maneuvers and basic 
rules of the road are presented to the participant during the scenarios. 
Performance will be quantified on a weighted composite score for time to 
scenario completion, pedestrian hitting, collisions, center lane crossing, off 
road accidents, stop sign and traffic light rules, and other driving errors.  
 
Strengthening task: Strengthening of wrist extensor muscles was chosen 
because wrist extensor strength is a key characteristic for participation in 
many upper extremity rehabilitation interventions (Hakkennes, and  Keating, 
2005). For training and testing, participants will sit with shoulder and forearm 
supported so motion is isolated to the wrist. A single column wall-mounted 
pulley with stackable weights of 2.5 lbs will be used. Prior to training and 
testing, participant will be guided through a warm-up to avoid injury and 
maximize performance. The warm-up exercises will include 2 sets (30 
seconds each) of wrist oscillations, 3 sets of each 10-seconds isometric 
contraction of wrist extensors, and 6-8 repetitions of 50% of 1 RM weight 
with the wrist extensors. Training will be initially set at 6 sets of 6-8 repetitions 
at 80% of 1 RM, which would be required high intensity to achieve training 
effects (Jenkins et al., 2017). The load will be increased if the subjects 
performs 4 sets of 6-8 repetitions with 80% of 1 RM. Training will be 
progressed by increasing the resistance if 8 repetitions are achieved on 4 of 
6 sets. We will provide 3-minutes of rest after each set to prevent muscle 
fatigue and soreness. 
 
Balance Task: The balance task requires subjects to stand on a movable 
platform (stability platform, model 16030L, Lafayette Instrument) and to keep 
the platform in a balanced, horizontal position (Taubert, Draganski et al. 
2010). This is a lab-based test. This task was selected because it simulates 
the balance required for daily function, and can be easily modified to the 

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appropriate level of difficulty in accordance with each subject’s motor 
abilities. 
 
Descriptive 
measures 
Demographic information, including age, dominant side, gender, ethnicity, 
race, level of physical activity, height, body weight, employment status, 
education level, co-morbidities, and current medications will be collected on 
all subjects on visit 1.  
Primary Outcome 
Measures 
The primary outcome measures are:  
1. Performance on the driving task 
2. Performance on the strengthening task 
3. Performance on the standing balance task  
 
Performance on the driving task: It will be measured by composite 
score. 
 
Composite score=  Time x Errors  
• 
Time=time to completion of entire driving scenario 
• 
Errors= number of pedestrian hitting, collisions, center lane 
crossing, off road accidents, stop sign and traffic light rules, and 
other driving errors.  
 
*Lower score would indicate better performance. 
 
Performance on the strengthening task will be assessed by- 
a. One repetition maximum (1RM) of wrist extensors: Maximum 
amount of force (lbs) that can be generated in one contraction 
(Shimano et al., 2006). It will be quantified as the maximum 
amount of weight (lbs) that participant can lift in one repetition.  
b. MVIC of wrist extensors: Maximum amount of isometric force 
(lbs) exerted by wrist extensor muscles against the 
dynamometer (Meldrum et al., 2007).  It is a standardized 
method for measurement of muscle strength using 
dynamometry.  
c. Amplitude of EDC: EMG data will be used to quantify the 
amplitude of EDC. Increase in the amplitude of EMG is an 
indicator of neurophysiological adaptation to strength training 
(Carroll et al., 2011; Christie and Kamen, 2010).  
 
Performance on the standing balance task will be quantified by the 
identifying the number of seconds in a 30-second trial that an individual is 
able to maintain the platform within ±3° of horizontal. 
 
Order of 
Experiment/Study 
Visits 
This study involves 10 total visits. Participants will be in the study for up to 6 
weeks.  Please refer to Figure 1 for details about study visits. 
 
Visit 1: A trained clinical interviewer will provide informed consent and 
conduct a structured clinical interview. Eligible individuals will be asked to 
complete descriptive measures. Next, subjects will have 15-20 min driving 
test in a simulated environment of a STISIM M300WS (Systems Technology, 
Inc.) driving simulator to quantify driving performance.  

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            Then, we will quantify muscle strength of the non-dominant wrist 
extensors by recording 1 RM. We will record the maximum amount of weight 
(lbs) that the participant will lift while performing wrist extension as 1 RM. 
Next, we will measure maximum voluntary isometric contraction (MVIC). We 
will ask the participant to produce maximum wrist extension force by pushing 
against the dynamometer placed on the dorsum of the wrist for three 
maximal-effort contractions lasting 5 seconds each with 2 minutes rest 
between each contraction. The average of three contractions will be 
considered as MVIC for wrist extensor muscles. We will also simultaneously 
record the electromyographic (EMG) activity of extensor digitorum 
communis (EDC) muscle while performing MVIC. EMG data will be gathered 
using 2-channel EMG system (Noraxon Inc, USA).The active electrodes will 
be placed on the belly of EDC. Two active electrodes will be separated with 
2 centimeters distance and the ground electrode will be placed on the bony 
prominence (lateral epicondyle) of the elbow.  
            Next, we will gather baseline measurements on balance task.  
            Subjects will then be randomized to their treatment group. After 
randomization, subjects will undergo RLIC or sham conditioning. This visit 
will take approximately: 2.5 hours. 
 
Visit 2: Subjects will undergo RLIC or sham conditioning. This visit will take 
approximately: 1 hour. 
 
Visit 3-8: Subjects will undergo RLIC or sham conditioning.  Next, behavioral 
training will commence (driving task, strengthening task, and balance 
training). The order of behavioral training task practice will be randomized. 
Visits 3-8 will occur every alternate day. These visits will take 
approximately: 2 hours. 
 
Visit 9: Subjects will complete post-testing which will include a) 15-20 min 
driving test; b) 1 RM and MVIC of the wrist extensor muscles on the training 
arm; c) EMG of the EDC muscle on the training arm, and d) balance testing. 
Visit 9 will be on the next day after visit 8. This visit will take 
approximately: 1 hour. 
 
Visit 10: Post-test performance assessment on driving test, 1 RM and MVIC 
and EMG of the EDC muscle on the training arm, and balance testing will be 
performed after 4-weeks from the visit 9. Participants will not receive RLIC 
or sham conditioning during the follow-up visits. Participants will fill out a 
survey on the second follow-up visit indicating whether they think that they 
received RLIC or sham treatment. This visit will take approximately: 1 
hour. 
 
Data Analysis 
Data will be analyzed using a mixed model ANOVA with time (pretest vs. 
posttest) as within subject factor and group (RLIC vs. sham treatment) as 
between subject factor.  
 
Safety 
Considerations & 
Monitoring 
The risks of participating in the rehabilitation intervention are minimal and 
are similar to the risks encountered during routine physical and 
occupational therapy services. The likely risks are- 
 

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1. Conditioning: bruising, discomfort, pain or tingling on the 
conditioning arm.  
        To avoid bruising from the pressure cuff, participant’s arm will 
be covered with a piece of cotton cloth. During each conditioning 
cycle, we will ask the participant about discomfort, pain or tingling in 
the conditioning arm. If the participant reports pain or tingling, we 
will reposition the pressure cuff on the arm and allow the participant 
to move the arm during 5-minutes of deflation cycle. 
2. Driving: motion sickness that can result in dizziness, nausea, 
yawning, perspiration, excessive blinking, vertigo, headache and 
general discomfort. There may be some anxiety while performing a 
simulated driving task.  
         To avoid motion sickness, the temperature of the driving 
simulation room will be regulated; we will keep the room cool and 
turn the fan on to maintain ventilation. We will also closely visually 
monitor early signs of motion sickness. Moreover, if the participant 
reports motion sickness during the training, we will immediately stop 
the simulator and will ask the participant to relax in the simulator 
chair until the symptoms subside. However, if motion sickness 
persists, participant will not resume the simulated driving training on 
that day and we will ask the participant to monitor the symptoms 
until before the start of the next visit. If motion sickness persists 
until next visit, we will discontinue participation from driving training. 
To reduce anxiety, we will reassure the participants that their 
performance will not impact their ability to drive on road. 
3. Strengthening: minor risk of injury to wrist muscles, wrist pain, 
muscle fatigue and delayed onset muscle soreness.       
           To avoid musculoskeletal injury, participants will perform 
warm-up exercises (gentle stretching of wrist muscles, wrist 
oscillations, isometric muscle contractions of the wrist muscle, and 
1 set of low-intensity weight lifting) for 5 minutes before starting the 
strengthening. Strength training on every alternate day should allow 
sufficient time to recover from muscle fatigue and delayed onset 
muscle soreness.  
4. Balance: small risk of falling from the balance board. 
            Subjects will be permitted to use a handrail as needed for 
safety during balance task and two research team members will 
supervise the balance performance. 
 
In order to monitor for further overall safety, we will continuously monitor 
lightheadedness, respiratory distress, cyanosis, and spasms. We will 
record and monitor heart rate, blood pressure, and oxygen saturation 
before, during, and after each session of RLIC. Sessions will be terminated 
if heart rate <40 bpm or >160bpm, systolic BP <85mm Hg or >160mmHg, 
diastolic BP <40 or >100 mm Hg or if O2 saturation <75%. Moreover, 
during the follow up session, all subjects will be asked to fill out a 
questionnaire related to the presence of adverse effects that resulted from 
participation in this study.  
Investigators 
PI: Catherine Lang PT, PhD 
Study Coordinator: Swati Surkar, PhD, PT 
 

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Number of Centers 
1 center: Washington University School of Medicine 
Key References 
Please see the reference list. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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References 
1. Gidday, J. M. (2006). "Cerebral preconditioning and ischaemic tolerance." Nat Rev 
Neurosci 7(6): 437-448. 
2. Saxena, P., et al. (2010). "Remote ischemic conditioning: evolution of the concept, 
mechanisms, and clinical application." J Card Surg 25(1): 127-134. 
3. Kharbanda, R. K., et al. (2009). "Translation of remote ischaemic preconditioning into 
clinical practice." Lancet 374(9700): 1557-1565. 
4. Hausenloy, D. J., et al. (2007). "Effect of remote ischaemic preconditioning on myocardial 
injury in patients undergoing coronary artery bypass graft surgery: a randomised 
controlled trial." Lancet 370(9587): 575-579. 
5. Botker, H. E., et al. (2010). "Remote ischaemic conditioning before hospital admission, as 
a complement to angioplasty, and effect on myocardial salvage in patients with acute 
myocardial infarction: a randomised trial." Lancet 375(9716): 727-734. 
6. Meng, R., et al. (2012). "Upper limb ischemic preconditioning prevents recurrent stroke in 
intracranial arterial stenosis." Neurology 79(18): 1853-1861. 
7. Ali, Z. A., et al. (2007). "Remote ischemic preconditioning reduces myocardial and renal 
injury after elective abdominal aortic aneurysm repair - A randomized controlled trial." 
Circulation 116(11): I98-I105. 
8. Addison, P. D., et al. (2003). "Noninvasive remote ischemic preconditioning for global 
protection of skeletal muscle against infarction." American Journal of Physiology-Heart 
and Circulatory Physiology 285(4): H1435-H1443. 
9. Cherry-Allen, K. M., et al. (2015). "Remote limb ischemic conditioning enhances motor 
learning in healthy humans." J Neurophysiol 113(10): 3708-3719. 
10. Christie, A., & Kamen, G. (2010). Short‐term training adaptations in maximal motor unit 
firing rates and afterhyperpolarization duration. Muscle & nerve, 41(5), 651-660. 
 
11. Kennedy, R.S., Lane, N.E., Berbaum, K.S., & Lilienthal, M.G. (1993). Simulator Sickness 
Questionnaire: An enhanced method for quantifying simulator sickness. International 
Journal of Aviation Psychology, 3(3), 203-220 
 
12. Cherry-Allen, K. M., Gidday, J. M., Lee, J. M., Hershey, T., & Lang, C. E. (2017). 
Remote Limb Ischemic Conditioning at Two Cuff Inflation Pressures Yields Learning 
Enhancements in Healthy Adults. Journal of motor behavior, 49(3), 337-348. 
 
13. Hakkennes, S., & Keating, J. L. (2005). Constraint-induced movement therapy following 
stroke: a systematic review of randomised controlled trials. Australian Journal of 
Physiotherapy, 51(4), 221-231. 
 

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14. Jenkins, N. D., Miramonti, A. A., Hill, E. C., Smith, C. M., Cochrane-Snyman, K. C., 
Housh, T. J., & Cramer, J. T. (2017). Greater Neural Adaptations following High-vs. Low-
Load Resistance Training. Frontiers in physiology, 8. 
 
15. Taubert, M., Draganski, B., Anwander, A., Müller, K., Horstmann, A., Villringer, A., & 
Ragert, P. (2010). Dynamic properties of human brain structure: learning-related 
changes in cortical areas and associated fiber connections. Journal of 
Neuroscience, 30(35), 11670-11677. 
 
16. Shimano, T., Kraemer, W. J., Spiering, B. A., & Volek, J. S. (2006). Relationship 
between the number of repetitions and selected percentages of one repetition maximum 
in free weight exercises in trained and untrained men. Journal of Strength and 
Conditioning Research, 20(4), 819. 
 
 
17. Meldrum, D., Cahalane, E., Conroy, R., Fitzgerald, D., & Hardiman, O. (2007). Maximum 
voluntary isometric contraction: reference values and clinical application. Amyotrophic 
Lateral Sclerosis, 8(1), 47-55. 
 
18. Carroll, T. J., Selvanayagam, V. S., Riek, S., & Semmler, J. G. (2011). Neural 
adaptations to strength training: moving beyond transcranial magnetic stimulation and 
reflex studies. Acta physiologica, 202(2), 119-140. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Visit 1        Visit 2 
Visit 3    Visit 4     Visit 5 
 Visit 6     Visit 7    Visit 8  Visit 9   FU1 
 
 
 
 
Figure 1. Remote limb ischemic conditioning (RLIC) involves 5 cycles of 5 minutes of upper 
extremity peripheral ischemia (induced by a blood pressure cuff inflated to 20 mmHg >systolic 
BP), alternating by 5 minutes of no ischemia. For 6 sessions (visit 3-8 for every alternate day), 
subjects receive a combinational intervention of RLIC (or sham) plus training. On training days, 
subjects undergo the RLIC and perform 15-20 minutes driving simulation, strengthening for 20-
30 minutes and15 minutes of balance training.  
 
 
 
 
 
 
 
 
 
 
Remote Limb Ischemic Conditioning (RLIC) + 
Driving Simulation (Day 3, 5, 7, 9, and 11 /15-20 min) 
Strengthening (Day 3, 5, 7, 9, and 11/20-30 min) 
Balance Training (Day 3-7/15 min)  
RLIC + 
Pre-
testing 
RLIC 
Post-
testing 

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Appendix 1 
 
No.______________  
 
 
 
 
 
 
Date____________________ 
SIMULATOR SICKNESS QUESTIONNAIRE 
Kennedy, Lane, Berbaum, & Lilienthal (1993)*** 
Instructions : Circle how much each symptom below is affecting you right now.  
1. General discomfort 
 
 
 
 None   
Slight   
Moderate  
Severe 
2. Fatigue 
 
 
 
 
 None   
Slight   
Moderate  
Severe 
3. Headache 
 
 
 
 
 None   
Slight   
Moderate  
Severe 
4. Eye strain  
 
 
 
 
None   
Slight   
Moderate 
 Severe 
5. Difficulty focusing  
 
 
 
None   
Slight   
Moderate  
Severe 
6. Salivation increasing   
 
 
None   
Slight   
Moderate  
Severe 
7. Sweating  
 
 
 
 
None   
Slight   
Moderate  
Severe 
8. Nausea 
 
 
 
  
None   
Slight   
Moderate  
Severe 
9. Difficulty concentrating  
 
 
None   
Slight   
Moderate  
Severe 
10. Fullness of the Head  
 
 
None   
Slight   
Moderate  
Severe 
11. Blurred vision  
 
 
 
None   
Slight   
Moderate  
Severe 
12. Dizziness with eyes open  
 
 
None   
Slight   
Moderate  
Severe 
13. Dizziness with eyes closed   
 
None   
Slight   
Moderate  
Severe 
14. *Vertigo 
 
 
 
 
None   
Slight   
Moderate  
Severe 
15. **Stomach awareness  
 
 
None   
Slight 
 
Moderate  
Severe 
16. Burping  
 
 
 
 
None   
Slight   
Moderate  
Severe  
 
Total: items 1 to 16 (scale of 0 to 3).  
 Nausea: items 1 + 6 + 7 + 8 + 12 + 13 + 14 + 15 + 16.  
Oculo-motor: items 2 + 3 + 4 + 5 + 9 + 10 + 11. 
 
* Vertigo is experienced as loss of orientation with respect to vertical upright. 
** Stomach awareness is usually used to indicate a feeling of discomfort which is just short of nausea.  
Last version : March 2013 ***Original version : Kennedy, R.S., Lane, N.E., Berbaum, K.S., & Lilienthal, 
M.G. (1993). Simulator Sickness Questionnaire: An enhanced method for quantifying simulator sickness. 
International Journal of Aviation Psychology, 3(3), 203-220