Effects of different intensities of resistance training with equated volume load on muscle strength and hypertrophy

Abstract

The present study investigated the effects of different intensities of resistance training (RT) on elbow flexion and leg press one-repetition maximum (1RM) and muscle cross-sectional area (CSA). Thirty men volunteered to participate in an RT programme, performed twice a week for 12 weeks. The study employed a within-subject design, in which one leg and arm trained at 20% 1RM (G20) and the contralateral limb was randomly assigned to one of the three conditions: 40% (G40); 60% (G60), and 80% 1RM (G80). The G20 started RT session with three sets to failure. After G20 training, the number of sets was adjusted for the other contralateral limb conditions with volume-matched. CSA and 1RM were assessed at pre, post-6 weeks, and post-12 weeks. There was time effect for CSA for the vastus lateralis (VL) (8.9%, 20.5%, 20.4%, and 19.5%) and elbow flexors (EF) (11.4%, 25.3%, 25.1%, and 25%) in G20, G40, G60, and G80, respectively (p > .05). G80 showed higher CSA than G20 for VL (19.5% vs. 8.9%) and EF (25% vs. 11.4%) at post-12 weeks (p < .05). There was time effect for elbow flexion and unilateral leg press strength for all groups post-12 weeks (p < .05). However, the magnitude of increase was higher in G60 and G80. In conclusion, when low to high intensities of RT are performed with volume-matched, all intensities were effective for increasing muscle strength and size; however, 20% 1RM was suboptimal in this regard, and only the heavier RT intensity (80% 1RM) was shown superior for increasing strength and CSA compared to low intensities.

Isometric training and long‐term adaptations: Effects of muscle length, intensity, and intent: A systematic review

“…However, high‐intensity training had a greater effect on muscle volume than the lower intensity (12.4%, ES = 0.28% vs 5.3%, ES = 0.26; P = 0.039) despite nearly identical effect sizes . These findings are in close agreement with recent studies and meta‐analyses that concluded that hypertrophic adaptations are similar if total load is equated and training intensity is >20% of maximal voluntary contraction …”

“…However, the studies cited in this review show a questionable relationship between intensity and force production adaptations (Figure ) . Consistent with recent original research and meta‐analyses, isometric training intensity does not appear to affect hypertrophic adaptations . While the lack of relationship between contraction intensity and force production is somewhat surprising, previous literature has reported that submaximal intensities can produce similar strength improvements when taken to failure, or when the volume is equated between groups .…”

“…44 These findings are in close agreement with recent studies and metaanalyses that concluded that hypertrophic adaptations are similar if total load is equated and training intensity is >20% of maximal voluntary contraction. 76,77 When the training volume is not equated between groups, it seems higher volumes are better for inducing muscular hypertrophy, regardless of contraction intensity. and "explosive" (40 × 1 seconds contractions, 80% of MVIC) isometric training.…”

“…13,[30][31][32]34,43,44,46,65 Consistent with recent original research and meta-analyses, isometric training intensity does not appear to affect hypertrophic adaptations. 76,77 While the lack of relationship between contraction intensity and force production is somewhat surprising, previous literature has reported that submaximal intensities can produce similar strength improvements when taken to failure, or when the volume is equated between groups. 77,118 These findings suggest that isometric training intensity is not important when aiming to improve force production or alter muscle morphology.…”

Triceps Brachii Muscle Strength and Architectural Adaptations with Resistance Training Exercises at Short or Long Fascicle Length

“…This training model was adopted to minimize inter-participant variability in training adaptations [9]. In addition, cross-education effect (i.e., adaptations in the contralateral arm), seems to be limited when both limbs are trained with different exercises, due to the fact that cross-education occurs only if there is an absence of any contralateral repeatable muscle activity [10]. Moreover, the acute training parameters were the same in the two interventions, except for the fascicle length during training.…”