There is no such thing as the quad muscle… but if you choose to stretch any of the muscles of the quad remember some simple MFS principles: 1. Fix the joint above and below the muscle first. 2. Use and respect the factors of progression and awareness principles with respect to the client you work with and the setting. For example, if you want to teach MFS of the rectus femoris and are doing it a group setting start with just the first one or two factors of progression first and on your third repetition progress to the final posture of the MFS. This will ensure that the client gains the awareness needed to stretch properly and thereby create a desired outcome of doing MFS in the first place.