Purpose – improve flexibility in the knee and hock joints. Dogs with an injury or older dogs can lose the ability to bend these joints to full flexion. This is obvious in a sit position when a dog is popping a leg out to the side or rolling on to a hip to avoid bending the joints properly

Placement of reward – For this I often place a container in front for them to focus on and reward them sometimes. 

Training Tips – Because we are manually doing this action on the dog, you want to make sure you aren't forcing the joint into a position that it can't do. Take it slowly and let the dog guide you how far you can go. Initially do it slowly from extension (straight leg) to flexion (joints bent). Make sure to keep the knee straight and don't let them turn their leg out. I place a palm on the outside of the knee to just keep that in correct alignment. You can then move to holding the leg bent for a short amount of time (5-10 secs) and even place your palm under their foot and gently bend the toes upwards as well