The Claim

In a study of 30 men, all resistance training intensities from 20% to 80% of one-repetition maximum (1RM) increased muscle strength and size when volume was matched over 12 weeks, though 20% 1RM was suboptimal compared to higher intensities.

Source: Effects of different intensities of resistance training with equated volume load on muscle strength and hypertrophy

What the research says

Supports is higher

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

Supports
40score
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

Lifting weights at different effort levels (from light to heavy) all made muscles bigger and stronger in men over 12 weeks, but the lightest effort wasn't as good as heavier ones.

See the scientific wording

All resistance training intensities from 20% to 80% of one-repetition maximum (1RM) increased muscle strength and size when volume was matched over 12 weeks in 30 men, though 20% 1RM was suboptimal compared to higher intensities.

What the research says

1 study

  1. Study: Effects of different intensities of resistance training with equated volume load on muscle strength and hypertrophy

    The study shows that lifting weights at different intensities all made muscles bigger and stronger when the total work was the same, but 20% was less effective than higher intensities, just like the claim says.

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

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