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

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. 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. 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). 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.