Effect Of Heavy Resistance Training On Low- And High-intensity Upper Body Work Capacity In College Women

Abstract

Heavy-resistance training programs may not improve high-intensity work capacity while significantly improving low-intensity work capacity in average college men. This phenomenon has not been documented in young women. PURPOSE: To assess the effect of heavy-resistance training on low-and high-intensity upper-body work capacity in college women. METHODS: Untrained women (n = 59, mean ± SD: age = 19.1 ± 1.1 y, height = 164.9 ± 5.3 cm, weight = 64.0 ± 13.0 kg) completed 12 weeks (3X/wk) of resistance training program. Muscular strength (1RM) and work capacity (WC) were measured using free weight bench press (BP) prior to and following the training. Following the pre-training 1RM testing, subjects were randomly assigned to low-intensity testing (LTI: 60% 1-RM, n = 25) or high-intensity testing (HTI: 85% 1-RM, n = 34) to perform repetitions-to-fatigue (RTF) in the BP. Work capacity (WC) was determined from repetition weight (RepWt) x RTF. Body composition was assessed via a generalized skinfold prediction equation. RESULTS: There were no significant differences between intensity groups at the pre-test in age, height, body mass, lean body mass, %fat, or 1RM BP (p>0.19). Following training, body mass decreased and lean body mass increased significantly for both groups with no significant difference between groups. LTI and HTI made equivalent (p>0.05) gains in 1RM BP (6.5 &#177 4.5 kg vs 6.7 ± 5.2 kg, respectively) and RTF (2.1 ± 7.3 vs 1.9 ± 4.5, respectively). RTF were completed with the same %1RM before and after training (LTI: 60.6 ± 1.8%; HTI: 84.1 ± 2.2%). Although both groups made approximately the same gain in RTF, the improvement by HTI group was significant (p<0.02) while that for LTI was not. LTI had a significantly greater WC than HTI at both pre-training (403 ± 132 vs 175 ± 81 kg·reps) and post-training (530 ± 162 vs 260 ± 104 kg·reps)(p<0.01), but the improvements made by each group were not significantly different (p = 0.10)(38 ± 42% vs 85 ± 136%). CONCLUSION: Resistance training can significantly increase strength in previously untrained women and may improve work capacity at both low-and high-intensity testing levels. The lack of difference between the groups in the present study is likely due to the large variability within each group which may be due in part to the unaccustomed nature of the endurance task in women.