Purpose: The aim of this study was to compare the effects of resistance training (RT) with an emphasis on either muscular strength-type RT or muscular endurance-type RT on measures of body composition.
Methods: Twenty-five resistance-trained men (age 28.4 ± 6.4 years; body mass 75.9 ± 8.4 kg; height 176.9 ± 7.5 cm) were randomly assigned to either a strength-type RT group that performed three sets of 6-8 repetition maximum (RM) with 3-min rest (n = 10), an endurance-type RT group that performed three sets of 20-25 RM with a 60-s rest interval (n = 10), or a control group (n = 5, CG). All groups completed each set until muscular failure and were supervised to follow a hyperenergetic diet (39 kcal·kg-1·day-1). Body composition changes were measured by dual-energy X-ray absorptiometry.
Results: After 8 weeks, we found significant increases in total body mass (0.9 [0.3-1.5] kg; p < 0.05; ES = < 0.2) and lean body mass (LBM) (1.3 [0.5-2.2] kg; p < 0.05; ES = 0.31) only in the strength-type RT group; however, no significant interactions were noted between groups.
Conclusions: Although only strength-type RT showed statistically significant increases in LBM from baseline, no between-group differences were noted for any body composition outcome. These findings suggest that LBM gains in resistance trained are not significantly influenced by the type of training stimulus over an 8-week training period.
Keywords: Body composition; Exercise; Fitness; Physiology; Training.