STRENGTH & PAW DOWN ACTION.

When the thigh starts to move downwards towards the ground, how much of that limb speed is governed by strength and roughly how much is governed by stretch reflex, how much is it just down to the fact that as the lower leg shoots forwards it’s going to help bring the thigh downwards. Also, is the stretch reflex power more a matter of strength or it’s naturally going to do a good job of throwing the leg down anyway? Anybody have any answers? I ask this partly becuase I don’t anderstand why the glutes and hams need so much power to throw the leg down quickly when there is little resistance. Even taking the reflex factor into consideration, that stretch tension only takes place to stop the thigh moving up too high, like a brake system, before the throw down. Why the need for great strength levals at those angles? My dumb ass only understands why strength at angles JUST before and during ground contact are important. Does someone need a 500+ pound squat to throw down their legs like sub 10 sec sprinter? Most people can cycle there legs 5 times per second when not touching the ground.