Effects Of High- And Low-load Resistance Training On Body Composition In Recreationally Trained Males

Abstract

Resistance training has been shown to improve body composition. PURPOSE: Determine the effects of resistance training at 30% or 85% of predicted 1-repetition maximum (1-RM) with regards to body mass, body fat percentage, and skeletal muscle mass. METHODS: 16 recreationally trained males (Mage = 20.4 ± 2.7 yrs) were recruited for this study. Participants were randomly assigned to one of two training groups: 30% or 85% of predicted 1-RM. Participants completed three sessions per week of a whole-body workout (back squat, deadlift, bench press, T-row, bicep curls, skullcrushers) over six weeks. Sessions consisted of two warmup sets and three working sets to failure at 30% or 85% of predicted 1-RM. Body composition data including body mass (BM), body fat percentage (%BF), and skeletal muscle mass (SMM) was collected at baseline and the end of the training program. A paired T-Test was used to assess differences in body composition from pre- to post-training. Significance was set a-priori at P < 0.05. RESULTS: There was a significant decrease in %BF over the course of the training program (P = 0.01), however no statistically significant changes were seen in SMM or BM (P > 0.56). CONCLUSIONS: Consistent with previous research, resistance training had a significant effect on body composition through a reduction in %BF. Both high- and low-load training contributed to these findings, but it should be noted that there were decreases in %BF in the 30% and increases in the 85% group (-0.75 vs +0.24%) indicating that low-load resistance may result in a more favorable body composition. Additionally, the observed increases in SMM in the 85% group indicate that high-load training may be more influential on improved muscle hypertrophy.