For women doing Les Mills BODYPUMP, using heavier weights (about 38% of your body weight) in squats makes certain leg muscles work harder than using lighter weights (23% of your body weight).

Women doing Les Mills workouts get more muscle activation in their quads, glutes, hamstrings, and calves when they squat deeper (90 degrees) compared to a more shallow squat (125 degrees).

For women doing squats in BODYPUMP classes, how deep they squat and how heavy the weight don’t affect each other when it comes to which muscles are working — each factor works on its own.

When women who lift weights do squats with a really heavy weight (close to their max), their leg and butt muscles have to work a lot harder than when they use lighter weights.

When you squat with heavier weights, your butt muscles (glutes) have to work way harder than your thigh muscles (quads), more than you'd expect just from the added weight.

When trained women lift heavy weights, thrusting the hips up with a barbell turns on the butt and hamstring muscles way more than doing a squat, but the front thigh muscle works about the same in both exercises.