The Claim

In resistance-trained men, performing high-intensity resistance training (3–5 repetitions at ~90% of 1RM with 3-minute rest intervals) for 8 weeks results in greater increases in lean arm mass compared to high-volume training (10–12 repetitions at ~70% of 1RM with 1-minute rest intervals), with a reported 5.2% increase in the high-intensity group versus a 2.2% increase in the high-volume group.

Source: The effect of training volume and intensity on improvements in muscular strength and size in resistance-trained men

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
54score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Cause and effect
1 study reviewed
In plain English

If you're a guy who's already been lifting weights, doing fewer reps with heavier weights and longer rests might build more arm muscle over 8 weeks than doing more reps with lighter weights and shorter breaks.

See the scientific wording

In resistance-trained men, performing high-intensity resistance training (3–5 repetitions at ~90% of 1RM with 3-minute rest intervals) for 8 weeks causes greater increases in lean arm mass compared to high-volume training (10–12 repetitions at ~70% of 1RM with 1-minute rest intervals), with a 5.2% increase in the high-intensity group versus 2.2% in the high-volume group.

What the research says

1 study
  1. Study: The effect of training volume and intensity on improvements in muscular strength and size in resistance-trained men

    The study looked at the same types of workouts and people described in the claim, and found that the high-intensity workout led to more arm muscle gain than the high-volume workout, just like the claim says.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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