AUTHOR=Vann Christopher G. , Sexton Casey L. , Osburn Shelby C. , Smith Morgan A. , Haun Cody T. , Rumbley Melissa N. , Mumford Petey W. , Montgomery Nathan T. , Ruple Bradley A. , McKendry James , Mcleod Jonathan , Bashir Adil , Beyers Ronald J. , Brook Matthew S. , Smith Kenneth , Atherton Philip J. , Beck Darren T. , McDonald James R. , Young Kaelin C. , Phillips Stuart M. , Roberts Michael D. 

TITLE=Effects of High-Volume Versus High-Load Resistance Training on Skeletal Muscle Growth and Molecular Adaptations

JOURNAL=Frontiers in Physiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2022.857555

DOI=10.3389/fphys.2022.857555

ISSN=1664-042X

ABSTRACT=<p>We evaluated the effects of higher-load (HL) versus (lower-load) higher-volume (HV) resistance training on skeletal muscle hypertrophy, strength, and muscle-level molecular adaptations. Trained men (<italic>n</italic> = 15, age: 23 ± 3 years; training experience: 7 ± 3 years) performed unilateral lower-body training for 6 weeks (3× weekly), where single legs were randomly assigned to HV and HL paradigms. Vastus lateralis (VL) biopsies were obtained prior to study initiation (PRE) as well as 3 days (POST) and 10 days following the last training bout (POSTPR). Body composition and strength tests were performed at each testing session, and biochemical assays were performed on muscle tissue after study completion. Two-way within-subject repeated measures ANOVAs were performed on most dependent variables, and tracer data were compared using dependent samples t-tests. A significant interaction existed for VL muscle cross-sectional area (assessed <italic>via</italic> magnetic resonance imaging; interaction <italic>p</italic> = 0.046), where HV increased this metric from PRE to POST (+3.2%, <italic>p</italic> = 0.018) whereas HL training did not (−0.1%, <italic>p</italic> = 0.475). Additionally, HL increased leg extensor strength more so than HV training (interaction <italic>p</italic> = 0.032; HV &lt; HL at POST and POSTPR, <italic>p</italic> &lt; 0.025 for each). Six-week integrated non-myofibrillar protein synthesis (iNon-MyoPS) rates were also higher in the HV versus HL condition, while no difference between conditions existed for iMyoPS rates. No interactions existed for other strength, VL morphology variables, or the relative abundances of major muscle proteins. Compared to HL training, 6 weeks of HV training in previously trained men optimizes VL hypertrophy in lieu of enhanced iNon-MyoPS rates, and this warrants future research.</p>