The math used in this study shows it’s almost certain that more lifting leads to more muscle and strength, and more frequent workouts lead to more strength—but not necessarily more muscle.
Scientific Claim
The posterior probability metric used in this meta-regression suggests a high likelihood of positive associations between resistance training volume and both hypertrophy and strength, and between frequency and strength.
Original Statement
“The posterior probability of the marginal slope exceeding zero for the effect of volume on both hypertrophy and strength was 100%, indicating that gains in muscle size and strength increase as volume increases. [...] The posterior probability for strength was 100%, suggesting strength gains increase with increasing frequency.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The claim accurately describes the statistical metric used (posterior probability) and its interpretation, without overstepping into causal language.
Evidence from Studies
Supporting (1)
The Resistance Training Dose Response: Meta-Regressions Exploring the Effects of Weekly Volume and Frequency on Muscle Hypertrophy and Strength Gains.
More weight training sets per week make you bigger and stronger, and training more often makes you stronger — but not necessarily bigger. The study found strong evidence for all these effects.