The effect of blood flow restriction training on strength and some physiological parameters

The aim of this study was to determine the effect of blood flow restriction (BFR) training on strength and some physiological parameters. A total of 30 adult males (20 experimental, 10 control) (CG) with a mean age of 21.10±2.38 years in the BFR group, 21.10±2.56 years in the traditional strength training (TST) group, and 22.70±1.57 years in the control group (CG) voluntarily participated in the study. The participants in the experimental group were divided into two groups as BFR and TST groups. The participants in the experimental group were scheduled 3 days a week for 8 weeks in the BFR method group. With the help of a sphygmomanometer, barbell squat and barbell curl exercises were performed at 20-30% of 1 Repetition Maximum (1RM) with a pressure of 120-140 millimeters of mercury (mmHg). The participants performed 4 sets of exercises with different number of repetitions (30-15-15-15). In the TST method group, barbell squats and barbell curls were performed at 70% of 1RM. The athletes performed 4 sets of 8-12 repetitions. CG was not included in any of the exercise programs. All participants (experimental and CG) before and after the study; Age, height, body weight, body mass index (BMI), body fat percentage (BFP), 1RM barbell squat and 1RM barbell curl, lean body mass (LBM), 60°/s right leg extension peak torque (60°/s right LEPT), 60°/s left leg extension peak torque (60°/s left LEPT), 180°/s right leg extension peak torque (180°/s right LEPT), 180°/s left leg extension peak torque (180°/s left LEPT), growth hormone (GH), creatine kinase (CK), testosterone, and myostatin values were determined. Non-parametric tests were used because the sample size was too small (nk=10) and the assumption of normality could not be met as a result of Z-scores and histogram examinations. The Wilcoxon test was used for pre-post comparison of dependent variables, Kruskal-Wallis H test for multiple groups and Mann-Whitney U test for paired groups were used to examine the difference between pre-post test differences. The significance level was set at p<0.05, and Bonferroni correction was applied to the p-value after multiple group comparisons. SPSS Statistics for Windows 25.0 (SPSS Inc. Chicago, Ill. USA) was used for statistical analysis of the data. There was no significant difference in body weight and BMI between BFR, TST and CG. While BMI decreased significantly in the BFR group, there was no significant difference in this variable in the other groups. While significant increases in LBM, 1RM barbell squat and 1RM barbell curl performance were observed in the BFR and TST groups, no statistically significant change in these variables was observed in the CG. When comparing the BFR and TST groups, 1RM barbell curl performance increased more in the BFR group, while no significant difference was found in 1RM barbell squat and LBM. Peak torque measurements showed significant increases in the BFR and TST groups, while a decrease was observed in the CG in favor of the pretest. In terms of hormone levels, significant changes in CK, GH, testosterone and myostatin levels were observed in the BFR group. Similarly, in the TST group, although an increase in CK, GH and myostatin levels was observed, no statistically significant difference was found in testosterone levels. In conclusion, it was found that BFR training provides a similar level of LBM gain, strength development and hormonal adaptation as TST, despite being performed at low loads. In particular, the superiority in 1RM barbell curl performance suggests that BFR training may be an effective alternative in terms of muscle strength gain. Key Words: Blood Flow Restriction; Hormone; Isokinetic Strength; Traditional Strength Training