Exploring the Dose-Response Relationship Between Estimated Resistance Training Proximity to Failure, Strength Gain, and Muscle Hypertrophy: A Series of Meta-Regressions.
Level 1 - systematic review of randomized trials
Meta-regression of resistance training trials
PubMed 38970765 · doi:10.1007/s40279-024-02069-2
What was done
Researchers conducted a series of exploratory multilevel meta-regressions and sensitivity analyses to examine the continuous dose-response relationship between proximity to failure and adaptations in muscular strength and hypertrophy. Proximity to failure was quantified as estimated repetitions in reserve (RIR), derived post-hoc from intervention descriptions in existing literature. Statistical models were adjusted for training load, volume-equating methods, intervention duration, and participant training status.
What was found
The abstract does not report specific numeric effect estimates or confidence intervals. In all best-fit models for muscular strength, the confidence intervals for the marginal slopes of estimated RIR crossed zero, indicating a negligible relationship between proximity to failure and strength improvements. For muscle hypertrophy, marginal slopes were consistently negative and excluded zero, showing that muscle size gains progressively increased as sets were terminated closer to failure (fewer RIR). Overall model fit for both outcomes was rated as modest.
Why it matters
These findings suggest that proximity to failure affects adaptations differently: maximal hypertrophy benefits from training closer to failure, whereas strength development can be achieved across a wider range of repetitions in reserve.
Limits
Repetitions in reserve were estimated post-hoc from study descriptions rather than directly controlled or recorded prospectively. The overall model fit was modest, and the analysis was explicitly exploratory. The abstract does not provide exact numerical effect sizes, the number of included studies, or total participant sample size.
Cited by
- supports Similar muscle hypertrophy occurs whether training with high-load, low-rep ranges or lower-load, high-rep ranges, provided sets are performed close enough to failure.
- supports Resistance training volume can be traded off against proximity to failure, such that performing extra sets while leaving several repetitions in reserve produces muscle hypertrophy comparable to fewer sets taken to complete muscular failure.
- supports Performing roughly 10 sets of exercise per muscle group per week, taken within 1 to 3 repetitions of muscular failure, is sufficient to stimulate muscle hypertrophy.