Literally massaging the tender areas, the attachments of the quads top at femur and behind the knee, as well as wherever the knee is numb. Its all about flow of blood as well as releasing excess swelling, lymphatic movement and promoting the nerves to awaken/ reconnect. Theres not much blood that flows naturally to the tendons of the body, muscles get plenty of blood but tendons (hamstrings) dont so bringing blood to them really helps as well. I believe its communicating with the body and being very conscious about what youre going through.