In a supine bridge position, leg lifts, weights, there's a lot of dynamic movement going on there so, make sure that you have control over pelvic posture, neutral, in your bridge. Feet hip width apart, line up your knee and your hip and I'm going to bridge, put the weight right here, away from the joint, on the meaty part of the thigh. I've got to have a very active hamstring and glute, in the supporting leg, soft neck, soft shoulders and extend. We've got a line and we keep the hips lifted, by maintaining contraction, and now we're going to add in lifting and lowering the leg but controlling momentum. Try it without weight first, then adding the weight in, will be an extra challenge. Staying lifted and controlling the momentum, up the leg. Contract and release, pushing energy out through the heel but not hyper-extending in the knee joint and, of course, breathing. My body moves as a result of contraction in the leg. Working each side, ten to fifteen reps, three sets.