King Grub
2016-09-13, 07:40
Background
A common perception held in mainstream fitness is that heavy resistance training will result in rapid muscular hypertrophy leading to a “bulky” appearance in females. A recent study demonstrated no difference in muscle hypertrophy improvements between 8 weeks of high- and low-load resistance training in trained men; however, this work has not been replicated in women. The purpose of this study was to investigate the effects of moderate- vs. high-load resistance training (RT) on changes in body composition and performance in females.
Methods
Thirty young women (20.3±1.5 years, 164±6 cm, 68.7±13.8 kg) without prior structured resistance training experience were recruited for this study. Body composition (BodPod), compartmental water (Bioelectrical Impedance), 7-site skinfold, and arm and thigh cross sectional area were assessed pre- and post-training. Performance testing consisted of vertical jump, 6 kg chest pass peak velocity, squat 1RM and military press 1RM. Following 2 weeks of familiarization training, subjects were matched for body composition and relative squat strength, and randomly assigned to either a high- (n=12; 4 sets of 5-6 repetitions) or moderate-load (n=11; 2 sets of 10-12 repetitions) group. Training was divided into two lower and one upper body training sessions per week and was performed on non-consecutive days for 8 weeks. Each training session consisted of 6-7 exercises performed to momentary muscular failure. Subjects were instructed not to change their dietary habits during the study. Statistical analyses were performed utilizing separate two-way repeated measures ANOVA for each criterion variable with an alpha level p ≤ 0.05.
Results
There were no significant group x time interactions for any variable assessed. There were no significant differences in pre- or post-training for sum of skinfolds or fat mass. Main effects for time (pre vs. post) include: a trend (p=.051) for an increase in arm CSA (95.9±17.4 vs. 99.1±13.9 cm2). Thigh CSA significantly (p<.001) increased (196.6±26.2 vs. 203.2±22.6 cm2). Body mass significantly (p=.029) increased (69.7±13.8 vs. 69.5 ±12.9 kg). Percent body fat significantly (p=.017) decreased (31.2±7.7 vs. 30.1±7.4). Lean mass significantly (p<.001) increased (46.5±5.9 vs. 48.0±6.2 kg). Total body water (TBW) significantly (p=.004) decreased (32.6±4.4 vs. 32.0±3.9 kg). TBW percent of fat free mass significantly (p<.001) decreased (69.2±4.2 vs. 67.6±3.8). Water free fat free mass significantly (p<.001) increased (14.1±1.4 vs. 15.4±1.6 kg). Vertical jump significantly (p=.003) increased (40.8±6.0 vs. 43.7±7.3 cm). Chest pass velocity significantly (p=.015) increased (3.98±0.48 vs. 4.19±0.45 m/s). Squat 1RM significantly (p<.001) increased (59.6±20.7 vs. 81.1±16.5 kg). Military press 1RM significantly (p=.001) increased (27.9±5.7 vs. 30.9± 4.2 kg). Effect size (Cohen’s d) differences were found for arm CSA (mod: .50, high: 0.30), TBW (mod: -.51, high: -.84), TBW percent FFM (mod: -.86, high: -1.38) vertical jump (mod: 1.54, high: .45) chest pass velocity (mod:
Conclusions
The results of this study indicate that both moderate- and high-load training are effective at improving muscle growth, body composition, strength and power in college-aged females. Small effect sizes for arm CSA and decreased TBW suggest neither moderate- nor heavy-load training will result in a “bulky” appearance.
The effects of moderate- versus high-load training on body composition, muscle growth, and performance in college aged females. Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo 2016.
A common perception held in mainstream fitness is that heavy resistance training will result in rapid muscular hypertrophy leading to a “bulky” appearance in females. A recent study demonstrated no difference in muscle hypertrophy improvements between 8 weeks of high- and low-load resistance training in trained men; however, this work has not been replicated in women. The purpose of this study was to investigate the effects of moderate- vs. high-load resistance training (RT) on changes in body composition and performance in females.
Methods
Thirty young women (20.3±1.5 years, 164±6 cm, 68.7±13.8 kg) without prior structured resistance training experience were recruited for this study. Body composition (BodPod), compartmental water (Bioelectrical Impedance), 7-site skinfold, and arm and thigh cross sectional area were assessed pre- and post-training. Performance testing consisted of vertical jump, 6 kg chest pass peak velocity, squat 1RM and military press 1RM. Following 2 weeks of familiarization training, subjects were matched for body composition and relative squat strength, and randomly assigned to either a high- (n=12; 4 sets of 5-6 repetitions) or moderate-load (n=11; 2 sets of 10-12 repetitions) group. Training was divided into two lower and one upper body training sessions per week and was performed on non-consecutive days for 8 weeks. Each training session consisted of 6-7 exercises performed to momentary muscular failure. Subjects were instructed not to change their dietary habits during the study. Statistical analyses were performed utilizing separate two-way repeated measures ANOVA for each criterion variable with an alpha level p ≤ 0.05.
Results
There were no significant group x time interactions for any variable assessed. There were no significant differences in pre- or post-training for sum of skinfolds or fat mass. Main effects for time (pre vs. post) include: a trend (p=.051) for an increase in arm CSA (95.9±17.4 vs. 99.1±13.9 cm2). Thigh CSA significantly (p<.001) increased (196.6±26.2 vs. 203.2±22.6 cm2). Body mass significantly (p=.029) increased (69.7±13.8 vs. 69.5 ±12.9 kg). Percent body fat significantly (p=.017) decreased (31.2±7.7 vs. 30.1±7.4). Lean mass significantly (p<.001) increased (46.5±5.9 vs. 48.0±6.2 kg). Total body water (TBW) significantly (p=.004) decreased (32.6±4.4 vs. 32.0±3.9 kg). TBW percent of fat free mass significantly (p<.001) decreased (69.2±4.2 vs. 67.6±3.8). Water free fat free mass significantly (p<.001) increased (14.1±1.4 vs. 15.4±1.6 kg). Vertical jump significantly (p=.003) increased (40.8±6.0 vs. 43.7±7.3 cm). Chest pass velocity significantly (p=.015) increased (3.98±0.48 vs. 4.19±0.45 m/s). Squat 1RM significantly (p<.001) increased (59.6±20.7 vs. 81.1±16.5 kg). Military press 1RM significantly (p=.001) increased (27.9±5.7 vs. 30.9± 4.2 kg). Effect size (Cohen’s d) differences were found for arm CSA (mod: .50, high: 0.30), TBW (mod: -.51, high: -.84), TBW percent FFM (mod: -.86, high: -1.38) vertical jump (mod: 1.54, high: .45) chest pass velocity (mod:
Conclusions
The results of this study indicate that both moderate- and high-load training are effective at improving muscle growth, body composition, strength and power in college-aged females. Small effect sizes for arm CSA and decreased TBW suggest neither moderate- nor heavy-load training will result in a “bulky” appearance.
The effects of moderate- versus high-load training on body composition, muscle growth, and performance in college aged females. Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo 2016.