Squats vs. Leg Extensions: Which Builds Thigh Muscles Better?
Comparison of Muscle Hypertrophy and Strength Adaptations Induced by Back Squat and Leg Extension Resistance Exercises.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Leg extensions produced significantly greater hypertrophy in the rectus femoris across all three measurement sites compared to back squats.
Most fitness advice assumes compound movements like squats stimulate more total muscle growth—but here, an isolation exercise outperformed it in a major thigh muscle.
Practical Takeaways
If you want to maximize rectus femoris growth, prioritize leg extensions. If you want to get stronger at squats, do squats. But if you only have time for squats, you’ll still get strong at leg extensions.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Leg extensions produced significantly greater hypertrophy in the rectus femoris across all three measurement sites compared to back squats.
Most fitness advice assumes compound movements like squats stimulate more total muscle growth—but here, an isolation exercise outperformed it in a major thigh muscle.
Practical Takeaways
If you want to maximize rectus femoris growth, prioritize leg extensions. If you want to get stronger at squats, do squats. But if you only have time for squats, you’ll still get strong at leg extensions.
Publication
Journal
Journal of strength and conditioning research
Year
2025
Authors
Witalo Kassiano, Bruna Costa, Gabriel Kunevaliki, Felipe Lisboa, Aline Prado, Luis Alves, Ian Tricoli, Natã Stavinski, Jarlisson Francsuel, Edilson S. Cyrino
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Claims (6)
Compound exercises involving greater total muscle mass do not produce superior hypertrophy in target muscles compared to isolation exercises when training volume and effort are equated.
Doing leg extensions makes the front thigh muscle grow more evenly along its length than doing squats, which don’t stimulate that muscle as much.
Squats make the lower part of the outer thigh muscle grow more than leg extensions do, probably because squats involve more hip and knee movement together.
If you want to get stronger at squats, doing squats is way better than doing leg extensions—but if you want to get stronger at leg extensions, both exercises work about the same.
Which leg exercise you choose matters: leg extensions grow the front thigh muscle more, squats grow the lower outer thigh more and make you stronger at squats—but both help you get stronger at leg extensions.