Measuring the Parameters of Maximum Muscle Strength, Muscle Mass, Muscle Damage in Active Adult Males after Low–Load High–Repetition with High–Load Low–Repetition Resistance Training

Objectives. This study aimed to evaluate the effects of high-load, low-repetition (HLLR) and low-load, high-repetition (LLHR) resistance training protocols on muscle strength, muscle mass, and muscle damage in active adult males. Materials and methods. This quasi-experimental study involved 28 active adult males aged 18-22 years with a body mass index of 19-23 kg/m2 selected to actively participate in the study and given HLLR and LLHR interventions with a frequency of 3x/week for 4 weeks. Data collection was carried out by assessing maximum muscle strength, muscle mass, and muscle damage between baseline (pre) and week 4 (post). Statistical analysis used an independent sample t-test, with a significance level of 95%. Results. There were significant differences between HLLR and LLHR interventions in max strength lower body (effect size (ES): 1.024), max strength upper body (ES: 1.241), and muscle mass (ES: 1.184) (p < 0.05). Meanwhile, CK activity was found to be significantly reduced in LLHR compared to HLLR (ES: 0.828) (p < 0.05). Conclusions. This study demonstrated that high-load, low-repetition (HLLR) training was more effective for increasing muscle strength and muscle mass, while low-load, high-repetition (LLHR) training reduced muscle damage, as indicated by lower creatine kinase levels.