The effect of circuit resistance training with three different intensities on muscle growth factors in obese men: a randomized controlled trial

PurposeResistance training through adjusting body composition can deal with the complications of obesity, but the most suitable type of resistance training for the obese population is not known. This study aimed to examine the effectiveness of three types of circuit resistance training (CRT) at different loads on muscle growth factors and lipid profiles of obese men.MethodsForty-four obese men (BMI >= 30) were randomly divided into four groups (n = 11): control, low-load CRT (40%1RM: LCRT), moderate (60%1RM: MCRT), and high (80%1RM: HCRT). The exercise protocol lasted for 12 weeks, 3 sessions per week, and included 8 stations in three sets with 20, 13, and 10 repetitions for each group, respectively. Before and after the intervention, body composition, lipid profile, and serum levels of decorin, TGF-beta 1, follistatin, and myostatin were measured. Analysis of covariance was used to interpret group differences.ResultsAfter 12 weeks of intervention, myostatin and TGF-beta 1 concentrations decreased, while follistatin and decorin levels increased significantly, irrespective of the training loads. Compared to the other two experimental groups, the HCRT group showed the greatest improvements. All loads of CRT improve body composition and lipid profile indices, and the greatest improvement was observed in both higher loads, favoring HCRT.ConclusionsAccording to the findings, by increasing the training intensity, in addition to obtaining the most performance and physical gains, further improvements occur in the lipid profiles, and muscle growth factors.Clinical trial registrationThe Iranian Registry of Clinical Trials (IRCT) has endorsed this research using the registration number IRCT20190627044037N1.