Effect of Resistance Training Frequency on Gains in Muscular Strength: A Systematic Review and Meta-Analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of comparative trials
PubMed 29470825 · doi:10.1007/s40279-018-0872-x
What was done
The authors systematically searched PubMed/MEDLINE, Scopus, and SPORTDiscus for studies comparing muscular strength gains across different resistance training frequencies (categorized as 1, 2, 3, or 4+ sessions per week). A random-effects meta-analysis evaluated strength gains across frequencies and conducted subgroup analyses for training volume (volume-equated vs. non-equated), exercise selection (multi-joint vs. single-joint 1RM), body region (upper vs. lower), training to failure, age, and sex. Methodological quality was appraised using the modified Downs and Black checklist.
What was found
Across 22 included studies (average Downs and Black score: 18, range 13–22; 4 rated good, 18 moderate), resistance training frequency had a significant overall effect on strength gains (p = 0.003), with effect sizes increasing from 0.74 (1 session/week) to 0.82 (2/week), 0.93 (3/week), and 1.08 (4+/week). However, in volume-equated studies, frequency had no significant effect on strength gains (p = 0.421). Frequency significantly affected strength for multi-joint tests (p < 0.001) but not single-joint tests (p = 0.324), upper body (p = 0.004) but not lower body (p = 0.070), young adults (p = 0.024) but not older adults (p = 0.093), and women (p = 0.030) but not men (p = 0.190). Training to muscular failure did not moderate outcomes.
Why it matters
This review demonstrates that training frequency increases strength primarily as a vehicle to accumulate greater total training volume rather than acting as an independent stimulus. When weekly volume is matched, training frequency can be chosen based on individual preference without compromising strength progress.
Limits
Most included studies evaluated untrained individuals, limiting generalizability to trained populations. Only 4 of the 22 studies were rated as good methodological quality. The abstract does not report overall participant sample size, confidence intervals, or specific exercise protocols.
Cited by
- supports Performing 15-minute resistance training micro-workouts 6 to 8 times per week yields similar strength and hypertrophy gains to 3 to 4 longer sessions of equivalent total volume.