ACSM 2026 Position Stand — What Actually Moves Strength and Muscle
0% read · 4 min left
The first ACSM resistance-training update since 2009 (137 systematic reviews, >30,000 people) found that doing resistance training at all matters most. Only a handful of variables reliably change results: heavier loads, full range, multiple sets, twice a week and training the lift early in the session for strength; ≥10 weekly sets and eccentric overload for size. Much of what lifters argue about didn't consistently matter.
Detail
What it is. "American College of Sports Medicine Position Stand. Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews" (Currier … Phillips, Med Sci Sports Exerc 2026; released 2026-03-17).
- It updates the 2009 stand "Progression models in resistance training for healthy adults".
- It synthesises 137 systematic reviews of randomised trials in healthy adults (≥18 yr) who trained for 6–52 weeks, covering more than 30,000 participants.
- ACSM's own summary: the most meaningful gain is "moving from no resistance training to any form of resistance training", and "the best resistance training program is the one you'll actually stick with."
Compared with doing nothing, resistance training improved strength, muscle size, power, endurance, contraction velocity, gait speed, balance and multiple physical-function outcomes. Circuit training, elastic bands and home-based training all count.
What enhanced strength (between-program comparisons):
- Higher loads (≥80% 1RM; dose-response).
- Full range of motion (see full-range-of-motion).
- Multiple sets (2–3 per session).
- Performing the exercise at the beginning of the session (see exercise-order).
- ≥2 sessions per week (upper limit undetermined; see frequency).
- Eccentric flywheel training vs standard training.
What did not consistently change strength:
- training to failure or fatigue
- machines vs free weights
- unstable vs stable surfaces
- fast (<2 s) vs slow (>2 s) reps
- morning vs evening
- short (<1 min) vs long (>1 min) rest between sets
- eccentric vs concentric contractions
- power-training techniques
- set structures (cluster, complex)
What enhanced muscle size:
- Higher weekly volume, ≥10 sets per muscle group per week (dose-response; see volume).
- Eccentric-only or eccentric-overload contractions (vs concentric-only).
What did not change muscle size:
- frequency, when total volume was equated (1 day/wk vs >5 days/wk)
- load from 30% up to 100% 1RM (see intensity)
- training to failure or fatigue (see autoregulation-rpe-rir, exhaustion-set)
- blood-flow restriction
- varying loads within reps
- fast (0.5 s) vs slow (8 s) reps (see tempo)
- power-training techniques
Power was enhanced by moderate loads (30–70% 1RM), low-to-moderate volume (≤24 reps × sets), Olympic-style lifts, and power training (a fast concentric phase). Power training also improved physical function.
Periodization and several other variables had insufficient or inconsistent evidence (see periodization-overview). The authors emphasise individualisation for adherence, enjoyment and safety.
Important caveats (from the paper):
- Most underlying reviews studied people with little or no training experience. The authors previously found experience had minimal impact on outcomes, but the evidence is weighted toward novices.
- "Did not consistently impact" is not the same as "never matters". Advanced lifters and specific goals can still benefit from these tools, and the stand calls for progressive training "with variable prescription".
- The stand grades evidence by review quality (AMSTAR). There's no standard certainty method for overviews of reviews, so conclusions vary in strength.
Key facts
- First ACSM resistance-training update since 2009: 137 systematic reviews, >30,000 participants (Med Sci Sports Exerc 2026).
- The biggest gain is going from no resistance training to any. Adherence is the top priority.
- Strength: ≥80% 1RM, full range, 2–3 sets, lift the exercise early in the session, ≥2 sessions/week.
- Size: ≥10 sets per muscle per week, and eccentric overload.
- Not consistently important: training to failure, machines vs free weights, rep speed, rest interval length, time of day. For size, also load (30–100% 1RM) and frequency when volume is equal.
- The evidence is mostly from newer lifters. "Didn't consistently matter" ≠ "never matters".
Connections
- volume — the ≥10 sets/week hypertrophy threshold.
- intensity — ≥80% 1RM for strength; 30–100% all build size.
- frequency — ≥2 sessions/week for strength; frequency doesn't matter for size when volume is equal.
- full-range-of-motion — full ROM enhanced strength.
- exercise-order — lifts done early in a session gained more strength.
- autoregulation-rpe-rir / exhaustion-set — training to failure wasn't required.
- tempo — rep speed didn't consistently matter.
- periodization-overview — insufficient or inconsistent evidence for periodization in healthy adults.
- lengthened-partials — the finer-grained range-of-motion evidence.