When beginners do leg exercises, the way their muscles turn on during the workout tends to match how much those muscles grow after 12 weeks — suggesting that which muscles work harder during exercise might predict which ones get bigger later.

53

Pro

0

Against

Evidence from Studies

Supporting (1)

53

Community contributions welcome

53

Hypertrophic Effects of Single- versus Multi-Joint Exercise: A Direct Comparison Between Knee Extension and Leg Press.

Cross-Sectional Study

Human

2026 Feb 5

The study found that which muscles worked harder during exercises like leg presses and knee extensions was the same as which muscles grew the most after 12 weeks, supporting the idea that muscle activation predicts growth.

Contradicting (0)

0

Community contributions welcome

No contradicting evidence found

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

Source Study

Hypertrophic Effects of Single- versus Multi-Joint Exercise: A Direct Comparison Between Knee Extension and Leg Press.

Score: 53

DOI: 10.1249/mss.0000000000003957

Similar Assertions

The way your muscles fire when you do leg presses vs. leg extensions matches up with which muscles end up getting bigger after training.

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The way your muscles fire when you do leg presses vs. leg extensions matches up with which muscles end up getting bigger after training.

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The way your muscles fire when you do leg presses vs. leg extensions matches up with which muscles end up growing bigger after training.

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The way your muscles fire when you do leg presses vs. leg extensions matches up with which muscles end up getting bigger after training.

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If you're new to working out, doing leg presses or knee extensions twice a week for 12 weeks will grow your thigh muscles about the same amount—so pick the one you like!

53

0

73%