For exercises that move just one joint—like bicep curls—lifting heavier weights leads to better strength gains than lifting lighter weights, even if both are done until exhaustion.

Scientific Claim

High-load resistance training is associated with greater increases in maximal strength for single-joint movements compared to low-load training, with gains of 9 ± 13% versus a slight decrease of -3 ± 10% in trained individuals over 9 weeks.

Original Statement

“but not in single-joint movements, where HL-RET was superior (9 ± 13% vs. -3 ± 10%)”

From study:Divergent Strength Gains but Similar Hypertrophy After Low-Load and High-Load Resistance Exercise Training in Trained Individuals: Many Roads Lead to Rome.

Evidence Quality Assessment

Claim Status

overstated

Study Design Support

Design cannot support claim

Appropriate Language Strength

association

Can only show association/correlation

Assessment Explanation

The abstract does not confirm RCT design or randomization; thus, causal language is inappropriate. The observed difference is descriptive, not proven causal.

Evidence from Studies

Supporting (1)

Divergent Strength Gains but Similar Hypertrophy After Low-Load and High-Load Resistance Exercise Training in Trained Individuals: Many Roads Lead to Rome.

Randomized Controlled Trial

Human

2025 Sep 1

The study found that lifting heavy weights made people stronger in exercises that move just one joint (like leg extensions), while lifting light weights didn’t help as much — sometimes even making them slightly weaker.

Contradicting (0)

No contradicting evidence found

Source Study

Divergent Strength Gains but Similar Hypertrophy After Low-Load and High-Load Resistance Exercise Training in Trained Individuals: Many Roads Lead to Rome.

Score: 25

DOI: 10.1152/japplphysiol.00353.2025

Similar Assertions

Whether you lift light weights many times or heavy weights fewer times—both can make you stronger in exercises like squats and deadlifts, as long as you push to exhaustion.

88%

Lifting heavier weights (fewer reps) leads to bigger strength gains than lifting lighter weights (more reps), even if both are done until exhaustion.

84%

Lifting heavier weights for nine weeks made young men stronger in a max lift test than lifting lighter weights, even when both groups worked until they couldn't do another rep.

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Whether you use light or heavy weights, your muscles can grow about the same amount if you train hard enough—both methods work for building muscle size.

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When people train one leg at a time, that leg gets much stronger than the other leg, even if the other leg didn’t do any training.

79%