spatterson said:I would think, biomechanically, that doing it on the floor would be harder on the lower back than doing it on a hyper machine. On a hyper you can rest the quads against the mat, on the floor, there's no support to the front of the leg. Your lower back compensates for the fulcrum in the movement. If your back is not easily irritated, I could see this working.
Just a "heads up" ...but this movement should be performed with a rounded back...do NOT arch your back. If you arch your back...it will do most of the work. With a rounded back the gluts and hams carry most of the load...which is what you want.