Resistance training (RT)-induced skeletal muscle hypertrophy is partly responsible for the RT-induced increase in strength. Previously, we reported that exercise repetition load played a minimal role in the promotion of RT-induced gains in hypertrophy and strength gains in RT-naïve participants performing RE to volitional failure. Thus, the main aim of this study were to determine the effects of 12 weeks of RT on muscle strength and hypertrophy in a trained population. 49 resistance-trained men (mean ± SEM, 23 ± 1 years, 85.9 ± 2.2 kg, 181 ± 1 cm) were randomly allocated into a lower load-high-repetition group (HR, n=24) or a higher load-low-repetition group (LR, n=25). Repetition load was set so that volitional lifting failure was achieved within the repetition ranges of 20-25 (~35-50% of 1RM) for HR or 8-12 for LR (~70-85% of 1RM). Strength as one repetition maximum (1RM) was assessed pre and post. Changes in lean body mass (LBM), appendicular lean mass (ALM) and leg lean mass (LLM) were assessed using dual-energy x-ray absorptiometry (DXA). There were significant increases in strength in all exercises with no differences between groups (p > 0.05) with the exception of bench press where LR showed a greater increase in 1RM than HR (p = 0.012). Similarly, LBM, ALM, and LLM increased significantly following training in the HR group (1.0 ± 0.9kg, p < .001; 0.8 ± 1.1 kg, p < 0.05; 0.7 ± 0.9 kg, p < 0.01 respectively) and the LR group (1.6 ± 1.4 kg, p < .001; 1.0 ± 1.2 kg, p < 0.05; 0.7 ± 1.0 kg, p < 0.01 respectively) with no significant differences between groups (all p > 0.05). These data show that RE performed to volitional failure using either HR or LR induces similar adaptations strength and lean mass accrual in young resistance-trained men. / Thesis / Master of Science in Kinesiology / Resistance training (RT) results in an increase in muscle growth and an increase in strength. Previously, we have shown in young untrained males, that when exercise is performed until failure, or until the weight can no longer be lifted, that gains in muscle and strength were similar with the use of either light or heavy weights. The purpose of the study was to determine the effects of 12 weeks of RT on muscle growth and strength in young men who were already regularly participating in resistance exercise when performing either lower load high repetition RT (HR) or higher load low repetition RT (LR). Maximum strength and changes in muscle mass were assessed prior to and upon completion of the training protocol. Following 12 weeks of RT both groups increased muscle mass and strength to a similar extent with the exception of bench press which increased more in the LR group.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/18125 |
| Date | 20 November 2015 |
| Creators | Oikawa, Sara Y |
| Contributors | Phillips, Stuart M, Kinesiology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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