When you do squats without fully straightening your knees and restrict blood flow, your thigh muscle gets much less oxygen during the exercise than when you're just sitting still.

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.

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

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.

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.

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.