Training · Moderate evidence
Training response varies widely between individuals
Following the same program, gains in strength and muscle mass range from negligible to substantial; study averages do not predict an individual's response.
Pooled analysis of training trials · 1 source · 2 min
What the studies show
- Gain heterogeneity was substantial across men and women of various ages.
- Age and sex explained little of the variation between individuals.
- Tracking your own response matters more than relying on group averages.
How Letz applies it
This is why Letz pairs general guidelines with individual data: parameters start within the literature-backed range and are adjusted based on logged history.
Who it applies to
Adults of various ages and sexes on standardized programs.
Limits
Does not identify low responders in advance; part of the variation stems from measurement error and adherence.
Sources
- Ahtiainen et al., Age, 2016 DOI 10.1007/s11357-015-9870-1
More in Training
- Resistance Training, Strength, and HypertrophyVarious training prescriptions improve strength and hypertrophy; heavier loads favor strength, and multiple sets favor hypertrophy.
- Weekly Volume: Sets per Muscle GroupMore weekly sets per muscle produce greater hypertrophy, with diminishing returns; for strength, moderate volumes already capture most of the gains.
- Frequency: training each muscle at least twice per weekTraining a muscle group twice a week is superior to once for hypertrophy; for strength, higher frequency helps primarily because it distributes volume more effectively.
- Load and rep rangeLight and heavy loads produce similar hypertrophy when sets are taken close to failure; heavy loads are superior for maximizing strength gains.