The Claim

The relationship between repetitions in reserve (RIR) and muscle hypertrophy is unclear because RIR is estimated indirectly from study descriptions, which limits the precision and reliability of the observed association.

Source: Exploring the Dose–Response Relationship Between Estimated Resistance Training Proximity to Failure, Strength Gain, and Muscle Hypertrophy: A Series of Meta-Regressions

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
39score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Correlation
1 study reviewed
In plain English

We don't really know for sure if doing exercises with more or fewer reps left in the tank helps you build more muscle, because scientists are just guessing how many reps people had left based on how the studies were written.

See the scientific wording

The relationship between repetitions in reserve (RIR) and muscle hypertrophy remains unclear due to the indirect estimation of RIR from study descriptions, limiting the precision and reliability of the observed association.

What the research says

1 study

  1. Study: Exploring the Dose–Response Relationship Between Estimated Resistance Training Proximity to Failure, Strength Gain, and Muscle Hypertrophy: A Series of Meta-Regressions

    The study found that lifting closer to failure might help muscles grow more, but since they had to guess how close people were to failure (not measure it directly), they can't be sure how strong that link really is—just like the claim says.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.