Which leg workout builds which muscles better?
Hypertrophic Effects of Single- versus Multi-Joint Exercise: A Direct Comparison Between Knee Extension and Leg Press.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Leg press did not significantly increase rectus femoris volume (+1.1%, P = 0.379), despite being a compound movement that involves knee extension.
Common belief is that compound lifts like leg press activate all quadriceps muscles more fully — but here, the rectus femoris barely grew, suggesting biomechanical limitations (like active insufficiency) may reduce its engagement.
Practical Takeaways
If you want bigger quads overall, either exercise works. If you want bigger front thighs, prioritize knee extensions. If you want bigger glutes and inner thighs, prioritize leg press.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Leg press did not significantly increase rectus femoris volume (+1.1%, P = 0.379), despite being a compound movement that involves knee extension.
Common belief is that compound lifts like leg press activate all quadriceps muscles more fully — but here, the rectus femoris barely grew, suggesting biomechanical limitations (like active insufficiency) may reduce its engagement.
Practical Takeaways
If you want bigger quads overall, either exercise works. If you want bigger front thighs, prioritize knee extensions. If you want bigger glutes and inner thighs, prioritize leg press.
Publication
Journal
Medicine and science in sports and exercise
Year
2026
Authors
Momoka Kinoshita, S. Maeo, Yuuto Kobayashi, Yuuri Eihara, Naoya Nishizawa, Yuki Kusagawa, Takashi Sugiyama, T. Wakahara, Hiroaki Kanehisa, Tadao Isaka
Related Content
Claims (10)
The rectus femoris muscle exhibits greater hypertrophic adaptation to isolated knee extension exercises than to compound movements involving hip and knee flexion due to biomechanical limitations in force production during multi-joint movements.
Isolation exercises targeting a single joint (e.g., leg extensions) produce greater hypertrophy in bi-articular muscles (e.g., rectus femoris) compared to multi-joint compound movements (e.g., squats) due to avoidance of active insufficiency.
The way your muscles fire when you do leg presses vs. leg extensions matches up with which muscles end up getting bigger after training.
Leg presses make your butt and inner thigh muscles bigger, but leg extensions don’t — if you want to grow those muscles, leg presses are the better choice.
Leg presses make your butt and inner thigh muscles bigger, but leg extensions don’t affect those muscles at all.