If you're a guy new to lifting and want your front thigh muscle to grow as much as possible, doing leg extensions with your hip more bent (40°) is probably better than keeping it straighter (90°).

Pro

Against

Evidence from Studies

Supporting (1)

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The effects of hip flexion angle on quadriceps femoris muscle hypertrophy in the leg extension exercise

Randomized Controlled Trial

Human

2025 Jan

The study found that bending the hip only 40 degrees during leg extensions made the front thigh muscle (rectus femoris) grow more than bending it 90 degrees — so if you want to build that muscle faster, use a less bent hip position.

Contradicting (0)

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No contradicting evidence found

Source Study

The effects of hip flexion angle on quadriceps femoris muscle hypertrophy in the leg extension exercise

Score: 54

DOI: 10.1080/02640414.2024.2444713

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