The American College of Sports Medicine has issued its first major update to its resistance training guidelines since 2009. The headline number is small.
Training all major muscle groups at least twice a week, with high effort and 2 to 3 sets per exercise, is enough to build strength and muscle in most healthy adults, according to a statement from the ACSM on the new Position Stand.
The recommendations pull together 137 systematic reviews involving more than 30,000 participants, published in Medicine & Science in Sports & Exercise.
"The best resistance training program is the one you'll actually stick with," said Stuart Phillips, distinguished professor of kinesiology at McMaster University, in an announcement from his university.
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What the guidelines say by goal
The advice is stripped to a few clear numbers per training goal.
For general strength, the guidance points to heavier loads at around 80 percent of one-repetition maximum, for 2 to 3 sets per exercise. For muscle growth, roughly 10 sets per muscle group across the week.
For power, the paper points to moderate loads of 30 to 70 percent of one-rep max, moved as quickly as possible during the lifting phase.
Barbells are not required. Elastic bands, bodyweight exercises and home routines can deliver measurable gains, provided the effort is high, according to the McMaster team behind the paper.
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The training-to-failure myth
For years, gym culture has insisted that a set only counts if the last rep is a grinding failure. The new review says the pooled evidence does not back that up.
Training to momentary muscular failure, choosing machines over free weights, and complex periodization schemes did not consistently improve outcomes for the average healthy adult, according to the ACSM.
That does not mean effort is optional. The guidelines still call for high-effort sets, just not necessarily the last, form-breaking rep.
The biggest change is the first one
The single biggest takeaway is not about sets or loads. It is about starting at all.
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The largest jump in strength, muscle size and physical function comes from moving from no resistance training to any regular resistance training, the ACSM says.
That framing lines up with a Harvard analysis of long-term data suggesting the biggest longevity gains from strength work land within the first couple of hours a week.
The full guidelines, titled "Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews," are available in Medicine & Science in Sports & Exercise. Anyone with heart disease, uncontrolled blood pressure or existing joint problems should check with a physician before starting a program.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.