Comparison of resistance training frequencies (2, 3, and 4 days/week) on strength, body composition, and anthropometric measures in untrained young men: An equal-set, intensity-matched randomized controlled trial

Abstract

This randomized controlled trial investigated the impact of different resistance training (RT) frequencies (2, 3, or 4 days/week) on muscular strength, body composition, and anthropometric measures in untrained young men. Training volume and intensity were matched across groups. Over an 8-week period, 41 previously untrained male university students and staff (aged 18–35 years; BMI 18.5–24.9 kg/m2) participated. Participants were randomly assigned to one of three training groups (2, 3, or 4 sessions per week) or to a control group. All training groups completed 12 sets per exercise per week, with intensity individualized based on one-repetition maximum (1RM) using a Daily Undulating Periodization (DUP) model. Key outcome measures included muscular strength (1RM in the barbell chest press, barbell row, Smith machine squat, and hip thrust), body composition (body weight (BW), fat-free mass (FFM), and body fat percentage (%Fat) assessed via bioelectrical impedance analysis (BIA)), and anthropometric measures (chest, upper-arm, and thigh circumferences). All variables were assessed before and after the training period. Data analysis involved paired-sample t-tests to evaluate within-group changes and an analysis of covariance (ANCOVA) to compare between-group differences, with baseline values entered as covariates. Results indicated that all training groups demonstrated statistically significant improvements in muscular strength (1RM across all exercises), body circumferences, and FFM following the intervention (p < 0.05 for all, with large effect sizes). Post-hoc analyses showed that all three training groups achieved significantly greater improvements in the measured variables compared with the nontraining control group (p < 0.05 for all). However, no significant differences were observed among the 2-, 3-, and 4-day training groups for any outcome (muscular strength, body circumferences, or FFM). These findings suggest that when total weekly volume and relative intensity are matched, RT performed 2, 3, or 4 days/week produces comparable gains in strength, body composition, and anthropometric measures in previously untrained young men.