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

Scientific Claim

High-load resistance training (≤8 RM) produces significantly greater strength gains than low-load training (>15 RM) in healthy young adults, with moderate-load training (9–15 RM) also superior to low-load, though high-load shows a nonsignificant trend toward greater gains than moderate-load.

Original Statement

“Muscle strength improvement was superior for both high-load and moderate-load compared with low-load RT... with a nonsignificant but superior effect for high compared with moderate load (SMD, 0.26–0.28, P = 0.068).”

From study:Resistance Training Load Effects on Muscle Hypertrophy and Strength Gain: Systematic Review and Network Meta-analysis

Evidence Quality Assessment

Claim Status

overstated

Study Design Support

Design supports claim

Appropriate Language Strength

probability

Can suggest probability/likelihood

Assessment Explanation

While the effect sizes are large and statistically significant for high vs. low load, the high risk of bias in blinding and randomization across studies limits definitive conclusions. The trend for high > moderate is not significant.

More Accurate Statement

“High-load resistance training (≤8 RM) likely produces greater strength gains than low-load training (>15 RM) in healthy young adults, with moderate-load training (9–15 RM) also likely superior to low-load, though high-load may only trend toward greater gains than moderate-load.”

Evidence from Studies

Supporting (1)

Resistance Training Load Effects on Muscle Hypertrophy and Strength Gain: Systematic Review and Network Meta-analysis

Systematic Review With Meta-Analysis

Human

2021 Jun 1

Lifting heavier weights (fewer reps) makes you stronger faster than lifting lighter weights (more reps), and even lifting medium weights is better than light ones — but the heaviest weights might be just a tiny bit better than medium, though not by much.

Contradicting (0)

No contradicting evidence found

Source Study

Resistance Training Load Effects on Muscle Hypertrophy and Strength Gain: Systematic Review and Network Meta-analysis

Score: 48

DOI: 10.1249/mss.0000000000002585

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