Phillips SM et al. (2026) · Medicine & Science in Sports & Exercise
First major ACSM update since 2009, based on 137 systematic reviews and 30,000+ participants. Flagship evidence base for resistance training prescription.
Every recommendation from your AI coach is grounded in peer-reviewed research. These are the papers that inform our programming decisions.
“Training all major muscle groups at least twice a week matters far more than chasing the idea of a ‘perfect’ or complex training plan.”— Stuart M. Phillips, PhD
First major ACSM update since 2009, based on 137 systematic reviews and 30,000+ participants. Flagship evidence base for resistance training prescription.
Consensus position stand covering volume, frequency, intensity, proximity-to-failure, exercise selection, and rest for maximizing hypertrophy. The single best citation for evidence-based hypertrophy programming.
Graded dose-response: each additional weekly set per muscle group yields ~0.37% additional hypertrophy. The foundational paper for volume-driven programming.
Updated meta-regression of 67 studies: 0.24% increase in hypertrophy per additional set at average 12.25 sets/week. The latest and largest volume dose-response data.
Hypertrophy is comparable across loading ranges from ~30% 1RM upward when sets are taken close to failure; strength gains are load-dependent.
When volume is equated, frequency does not significantly impact hypertrophy. Users should pick frequency for adherence.
Hypertrophy maximized at 0-3 RIR for moderate-to-heavy loads. Going to absolute failure is not necessary and increases fatigue disproportionately.
Original validation of the RIR-based RPE scale for resistance training. The foundation for autoregulated programming.
No significant difference between linear and daily undulating periodization for hypertrophy when volume-equated. Pooled SMD = -0.02.
Clinical guide to using RIR in programming — directly applicable to autoregulated workout logging.
Midpoint deload preserved hypertrophy but slightly reduced strength gains vs continuous training. Deloads should be triggered by fatigue signals, not blindly scheduled.
Both linear and undulating periodization work for strength; neither is clearly superior when volume-equated.
Inter-individual variability in 1RM gain ranges from 0% to 250% over 12 weeks across 585 participants. The empirical justification for autoregulation over fixed progression schedules.
Target weight loss 0.5-1%/week; protein 2.3-3.1 g/kg LBM/day to preserve muscle in a deficit. The anchor for fat-loss programming.
150-300 min/week moderate or 75-150 min vigorous aerobic + muscle-strengthening 2+ days/week for adults.