Effect of Blood Flow Restriction Exercise on Acute Systemic Irisin, Myostatin and Decorin Levels
Phase: NA
Conditions: Muscle Hypotrophy
Sponsor: Ege University

 
 
Effect of Blood Flow Restricted Exercise on Acute Systemic 
Irisin, Myostatin and Decorin Levels 
 
 
 
 
Document date: 10/04/2022 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
The aim of the study is to measure and compare acute systemic irisin, myostatin and decorin 
levels after a single session of blood flow restricted resistance exercise and resistance exercise 
without blood flow restriction in healthy, trained male participants aged 18-35 years. For this 
purpose, a total of 22 people will be included in the study. Participants will be randomly 
allocated to 2 exercise groups as resistance exercise with blood flow restriction (BFR-RE) and 

resistance exercise without blood flow restriction (HL-RE) and will be subjected to cross-
over. In the HL-RE intervention, the exercise will be performed with a loading of 80% of 1 
RM, with 4 sets x 7 repetitions, with 60 seconds of rest between sets. In the BFR-RE 
intervention, the exercise will be done as a set of 30 repetitions with a loading of 30% of 1 
RM and an additional 3 sets x 15 repetitions, with 30 seconds rest between sets. Total exercise 
volumes were tried to be equalized and skeletal muscle hypertrophy was selected in 
accordance with exercise guidelines. In both groups, bilateral leg extention exercise will be 
performed using the leg extention tool for resistance exercise. In the blood flow restriction 
group (BFR-RE), the cuff will be placed in the proximal region of the thigh bilaterally, 
inflated to a pressure equivalent to 50% of the estimated arterial occlusion pressure (AOP), 
and leg extention exercise will be performed under this condition. In the BFR-RE group, the 
blood flow restriction time will be between 5-10 minutes. Exercise sessions will be conducted 
under supervision. Venous blood samples will be collected from the arm antecubital region of 
the participants just before the exercise session, immediately after the exercise, and 1 hour 
after the exercise. Plasma irisin, myostatin and decorin levels will be measured from the 
samples taken. It is well known that resistance exercise is important in maintaining and 
increasing muscle mass (hypertrophy). Studies have shown the involvement of certain 
myokines in skeletal muscle hypertrophy, although few studies have been conducted on the 
systemic response of myokines to BFR-RE that may play a potential role in hypertrophy. 
Therefore, the planned study aimed to reveal the similarities or differences in the systemic 
myokine response between BFR-RE and HL-RE. 
22 male participants between the ages of 18-35 will be included in the study. Participants 
must have been doing resistance exercises for at least one year. In the study, plasma irisin, 
myostatin and decorin myokine levels will be measured from venous blood samples to be 
taken from the participants. Sample size was analyzed using 2-group repeated measures (three 
time points for each period) crossover design, single-factor, repeated measure methodology 
(repeated measure anova). A sample of 19 athletes measured at 6 time points reaches 80% 
power to detect differences between averages using the F-Test at a significance level of 0.05. 
The effect size was set as f 0.25 (medium) and the correlation between measurements was 
taken as 0.5. The accepted sample size for equal group size is 20. Considering loss of follow-
up or non-compliance with the experiment, the final sample size was 22 with a 10% attrition 
rate. 
A randomization algorithm (Maximum Allowed % Deviation = 10%) was applied using 
PASS software 11.0 (NCSS LLC, Kaysville, UT) to generate a randomization list that would 
allow participants to be assigned to two groups of 11 each. 
The parameters to be examined in statistical analyzes are plasma irisin, myostatin and decorin 
levels. Statistical analyzes IBM SPSS Statistics 25.0 (IBM SPSS Statistics for Windows, 
Version 25.0. Armonk, NY: IBM Corp.) package program and R 3.5.3 software (R software, 
version 3.5.3, R Foundation for Statistical Computing, Vienna, Austria ; http://r-project.org). 
Significance level was determined as 0.05 in all analyzes. Time group interaction will be 
analyzed at a significance level of 0.1. In the study, numerical data will be summarized with 
mean, standard deviation, median, minimum and maximum values, and categorical data will 
be summarized using frequency and ratio values. The assumption of normality in numerical 
variables will be checked with the Shapiro Wilk test at each group and time point, and in 
parallel with the results, the time-dependent change in the groups will be analyzed 

parametrically with the linear mixed model (linear mixed model) or non-parametrically with 
the Brunner-Langer model. If the interaction is found to be significant, subgroup analyzes will 
be made, both within and between groups. Bonferroni correction will be used for multiple 
comparisons. Qualitative variables will be analyzed with Pearson Chi-square test, while all 
quantitative demographic data between groups will be analyzed with independent group 
ANOVA or Kruskal-Wallis test. 
Study Protocol: 
-Informing the participants about the study and obtaining their consent. 
-Recording the demographic information of the participants. 
-Making anthropometric measurements before the interventions, filling out the EGZ-A+ 
questionnaire, calculating HRR, making 1RM and AOP measurements. 
-Exercise interventions will be done at the same times of the day and at 1 week intervals. 
-Before the exercise interventions, warm-up on the bicycle ergometer at 50% of the HRR for 
10 minutes, followed by lower extremity stretches. 
- In the HL-RE intervention, the exercise will be performed with 4 sets x 7 repetitions, with a 
60-second rest between sets, with the load on the knee extension device being 80% of 1 RM. 
Venous blood samples will be taken immediately before exercise, immediately after exercise, 
and 1 hour after exercise. 
- In the BFR-RE intervention, the cuff will be placed in the proximal thigh region and inflated 
with the help of the cuff to the pressure corresponding to 50% of the AOP, and the exercise 
will be performed under this condition. The exercise will be performed as a set of 30 
repetitions with a load of 30% of 1 RM on the knee extension device and an additional 3 sets 
x 15 repetitions, with 30 seconds rest between sets. Venous blood samples will be taken 
immediately before exercise, immediately after exercise, and 1 hour after exercise. 
-In order to increase the comfort of the participant, blood samples will be collected by 
experienced people through a vein to be opened in the arm antecubital region.