Evidence for an Upper Threshold for Resistance Training Volume in Trained Women

INTRODUCTION: The purpose of the present study was to compare the effects of different volumes of resistance training (RT) on muscle performance and hypertrophy in trained women.

METHODS: The study included 40 volunteers that performed RT for 24 wk divided into groups that performed 5 (G5), 10 (G10), 15 (G15), and 20 (G20) sets per muscle group per session. Ten-repetition maximum (10RM) tests were performed for the bench press, lat pulldown, 45° leg press, and stiff-legged deadlift. Muscle thickness (MT) was measured using ultrasound at biceps brachii, triceps brachii, pectoralis major, quadriceps femoris, and gluteus maximus.

RESULTS: All groups significantly increased all MT measures and 10RM tests after 24 wk of RT (P < 0.05). Between-group comparisons revealed no differences in any 10RM test between G5 and G10 (P > 0.05). G5 and G10 showed significantly greater 10RM increases than G15 for lat pulldown, leg press, and stiff-legged deadlift. 10RM changes for G20 were lower than all other groups for all exercises (P < 0.05). G5 and G10 showed significantly greater MT increases than G15 and G20 in all sites (P < 0.05). MT increased more in G15 than G20 in all sites (P < 0.05). G5 increases were higher than G10 for pectoralis major MT, whereas G10 showed higher increases in quadriceps MT than G5 (P < 0.05).

CONCLUSIONS: Five to 10 sets per week might be sufficient for attaining gains in muscle size and strength in trained women during a 24-wk RT program. There appears no further benefit by performing higher exercise volumes. Because lack of time is a commonly cited barrier to exercise adoption, our data support RT programs that are less time consuming, which might increase participation and adherence.