Research

Mixed

Resistance training interventions introduce significant interindividual response variation (heterogeneity) in strength and hypertrophy outcomes beyond random measurement error, as evidenced by increased variance in change scores compared to non-training controls.

Do not assume that a resistance training program that works for others will work identically for you. The paper confirms that resistance training introduces significant individual variability in strength and muscle growth. If you are not progressing, it may be due to your specific 'trainability' or response pattern rather than poor adherence. Consider that personalized adjustments to volume, intensity, or exercise selection may be necessary, as 'one size fits all' prescriptions are statistically less likely to optimize individual outcomes.

GoodSupportsHIGH confidence
both the SDir (figure 4) and lnV R (figure 5) were also positive for both strength... and hypertrophy outcomes... indicating that exposure to the RT interventions may have introduced additional variance over and above random error, potentially suggesting the presence of interindividual response variation.
James Steele et al. · Journal of Sports Sciences · 2023

Why this rating

Based on a meta-analysis of 111 studies from a previous systematic review, using robust multilevel mixed-effects models.

Source

Meta-analysis of variation in sport and exercise science: Examples of application within resistance training research

James Steele et al. · Journal of Sports Sciences · 2023

DOI 10.1080/02640414.2023.2286748

Meta-analysis · 111 studiesCited 24×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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