I bought this after full knee replacement, and as Physical Therapy appts were finishing but I need to continue to stretch, bend the knee and pull the leg as close to the body as possible and "Hold the postion for 5 - 10 seconds". Inserting my foot, into a loop and pulling my foot towards me, (1 foot strap, at the top of the heel), allowed me to bend and pull the knee closer and hold longer, without my foot slipping forward, especially when doing the exercises on the bed (top coverlet or bed sheeSee full review