Keeping your knees bent longer during squats (without locking them) makes your thigh muscle work harder and use up more oxygen than fully straightening your legs — especially when blood flow is restricted.

If you keep your knees bent while squatting (no locking), your thigh muscle gets more oxygen-starved than if you lock your knees at the top — even if you do it for the same amount of time.

When you squat all the way down without locking your knees, your thigh muscle gets more oxygen-deprived than if you stop short and lock your knees — which might help build muscle.

Even short, locked squats (8 seconds) can make your thigh muscle very low on oxygen — but only if you keep your knees bent and restrict blood flow.

Even if you lock your knees at the top of a squat, your thigh muscle still gets less oxygen during the exercise than when you're just standing still — but not as much as if you keep your knees bent.

When you restrict blood flow to your thigh while squatting, your muscle gets much less oxygen — no matter how you move your knee.