Getting stronger from lifting weights doesn’t always mean your muscles are getting bigger—and vice versa. Strength and size don’t go hand in hand.

Scientific Claim

The variation in resistance training-induced muscle hypertrophy is not meaningfully linked to changes in muscle strength, suggesting that muscle size gains and strength gains are driven by different physiological mechanisms.

Original Statement

“There is negligible shared variance between RET-induced increases in muscle size and strength.”

From study:Resistance training load does not determine resistance training-induced hypertrophy across upper and lower limbs in healthy young males.

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

association

Can only show association/correlation

Assessment Explanation

The claim uses 'negligible shared variance,' which is a precise correlational term. The study design supports this type of relationship analysis.

Evidence from Studies

Supporting (1)

Resistance training load does not determine resistance training-induced hypertrophy across upper and lower limbs in healthy young males.

Randomized Controlled Trial

Human

2025 Dec 31

Even when people lift different weights and get bigger muscles, their strength doesn’t always increase the same way — meaning growing muscles and getting stronger are controlled by different things in the body.

Contradicting (0)

No contradicting evidence found

Source Study

Resistance training load does not determine resistance training-induced hypertrophy across upper and lower limbs in healthy young males.

Score: 46

DOI: 10.1113/JP289684

Similar Assertions

Getting stronger from lifting weights doesn’t always mean your muscles are getting bigger—and vice versa. Strength and size don’t go hand in hand.

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People grow muscle at very different rates — but each person tends to grow their arms and legs similarly, no matter what weight they use. This means your genes and biology matter more than how heavy your weights are.

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In trained individuals, higher resistance training volumes lead to concomitant increases in both muscle hypertrophy and maximal strength.

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