Resistance Training Frequency and Muscle Hypertrophy: A Systematic Review and Meta-Analysis of Volume-Equated Trials
Year: 2026
Type: preprint
Study designs: Systematic Review, Meta-Analysis
Abstract: ABSTRACT Weekly training volume is the primary driver of resistance-training hypertrophy, but the independent role of frequency can be isolated only when weekly volume is equated. We quantified the effect of training frequency on hypertrophy across one to three volume-equated sessions per muscle per week. Following PRISMA 2020, five databases were searched to October 2026 for trials of at least six weeks that equated weekly volume between per-muscle frequencies and measured muscle size. One change-score standardized mean difference per trial (Hedges g; negative favoring higher frequency) was pooled with a random-effects model, and certainty was rated with GRADE. Sixteen trials (380 participants) were pooled. The frequency effect was trivial and non-significant (g = -0.06; 95% CI -0.24 to 0.13; I² = 0%; prediction interval -0.26 to 0.14); the interval admits at most a small effect favoring the higher frequency. Contrast-specific estimates were non-significant, trivial for one versus two and two versus three sessions and small for one versus three (g = -0.23; 95% CI -0.57 to 0.10), and no moderator was significant, although the moderator analyses could detect only large effects. Certainty was low to very low. Within this range, the data lack the precision to distinguish one, two or three sessions at a fixed weekly volume. Most trials measured muscle thickness, which does not track whole-muscle growth reliably.
Source: medRxiv
Authors: Anthony Gordon Boutagy, Mark McKean
Institution: University of the Sunshine Coast
Language: English
Subfield: Orthopedics and Sports Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7221181649