The Training Signal #28: ACSM Just Rewrote the Rules on Resistance Training
The American College of Sports Medicine just published updated resistance training recommendations for healthy adults — the first major revision since 2009. For 17 years, the global scientific benchmark for strength training was frozen. It isn't anymore.
The new Position Stand synthesizes 137 systematic reviews covering more than 30,000 participants. It's the most comprehensive evidence base ever assembled on the topic. Here's what you need to know.
The headline finding: just start
The most important conclusion from the new guidelines isn't a complex protocol. It's this: the biggest jump in benefits happens when you go from zero resistance training to any resistance training.
ACSM is emphatic about it. If you're already training consistently, you can optimize. But if you're not training at all, the programming details barely matter — what matters is starting.
That shift in tone is significant. Previous guidelines focused on specific parameters: exact sets, loads, frequencies. The new document makes it clear that precision only matters once you're already in the habit.
Frequency: hit every muscle group twice a week
The primary target for most adults: work all major muscle groups at least twice per week. That's the frequency that produces the most meaningful strength and hypertrophy gains for a reasonable time investment.
You don't need a 5-day split to make progress. Two solid full-body sessions per week covers the vast majority of health and performance goals.
Hypertrophy: 10 sets per muscle, any load that challenges you
To build muscle, the new guidelines set a minimum threshold of 10 sets per muscle group per week. That's the dose that produces a meaningful hypertrophic response based on available evidence.
On loads: anything from 30% to 100% of 1RM works — as long as you take each set close to failure. That's the key variable. The absolute load matters less than the relative effort.
In practice: you can build muscle with light weights and high reps, or heavy weights and low reps. What doesn't work is cruising through sets well short of failure.
Strength: heavy, early, twice a week
For maximal strength, the guidelines get more specific:
- At least 80% of 1RM
- Full range of motion
- 2 to 3 sets per exercise
- Key lifts placed early in the session (when you're fresh)
- Minimum twice per week
Exercise order is often overlooked. Placing strength work at the end of a session, after volume work, compromises the neurological adaptations you're after. If strength is the goal, it goes first.
Power: moderate load, explosive intent
For developing power — the ability to produce force quickly — ACSM recommends moderate loads with intentionally explosive concentric phases. Not maximal loads, not high volume. Movement intent trumps absolute load.
Safety: confirmed, unambiguously
The document addresses this directly: resistance training is safe. Safety data from more than 38,000 participants confirms it does not increase the risk of serious adverse events, even in people with cardiovascular disease — when implemented progressively.
That's critical information for coaches working with older populations or clinical populations. Resistance training isn't contraindicated by default. In many cases, the opposite is true.
What this actually changes for you
If you're already training twice a week with solid progression, these guidelines don't change your approach. You're already where the evidence points.
If you were still searching for THE perfect protocol before committing, ACSM's answer is clear: it doesn't exist. What exists is any consistent resistance training practice — which produces measurable benefits within weeks.
The next question isn't what's the optimal frequency. It's: when's your next session?
Sources: ACSM Position Stand 2026 — 2 Minute Medicine