Hi, today morning I tried the "Drill 4: Reverse Lunge with Rotation (rebuilding the sling system)" but when doing this exercise, my knees started to hurt and I feel them now during the day too. It felt like the muscles going up from the knee (around the knee?) were being strained too much while going towards the ground (while doing the lounge basically, the back knee hovering was hurting). How can I prevent this from happening?