Fat-free mass accretion — limits, targets and best practices (narrative review): drug-free men typically gain ~1.4 kg of fat-free mass over 12 weeks of resistance training (IQR 1-2 kg); practical FFM-index ceiling ~28.5; modest surplus of 0.1-0.25% body weight gain per week, protein 1.6-2.2 g/kg/d
The review examines physiological limits, longitudinal projections and best practices for hypertrophy with a focus on bodybuilding and physique sport, and models short- and long-term growth trajectories for male and female lifters. Content from the abstract (Crossref record; no PubMed abstract found).
Key Results
Drug-free male athletes typically gain roughly 1.4 kg of fat-free mass over 12 weeks of resistance training (interquartile range 1-2 kg).
A practical upper limit for FFM index in drug-free men is approximately 28.5 (higher values seen with elevated adiposity or anabolic steroid use).
Women have roughly 70% less FFM at baseline but make proportionally similar gains.
Training: moderate loads (6-12 RM), near muscular failure, 12-30 fractional sets per muscle group per week.
Nutrition: modest caloric surpluses (0.1-0.25% body weight gain weekly), protein 1.6-2.2 g/kg/d, carbohydrate ≥3 g/kg/d, fat 0.5-1.5 g/kg/d; creatine and protein supplementation have established benefits.
Recurring multicompartment body-composition assessments are recommended for monitoring.
Practical Application
"How much muscle can I realistically add, and how fast should the scale move?" A 2026 review puts a typical 12-week gain for drug-free men at ~1.4 kg of fat-free mass (IQR 1-2 kg) and recommends a modest surplus of 0.1-0.25% of body weight per week — a practice target from normative data, not a tested threshold.
For an 80 kg trained athlete that is about 80-200 g a week (arithmetic, not from the paper).
Limitations
Narrative review; targets are recommendations, not trial results; no PubMed record found.
Physique-sport focus; the normative FFM numbers quoted in the abstract are for drug-free men.
How this entry was checked and changed
Why this level
narrative review without systematic method