Stretching Tips- ~Clarity~ Zaichik Stretching System and Rectus Femoris Kinesiology
~Clarity~ is Zaichik Stretching System (formerly known as Kinesiological Stretching) focusing on Rectus Femoris. Rectus Femoris Femoris is one of the four heads of the Quadriceps Muscle. The other three being Vastus Lateralis, Vastus Medialis and Vastus Intermedius. While all four heads extend the knee, Rectus Femoris is unique, because it also flexes the hip.
Because Zaichik Stretching Systems take advantage of multiple muscle actions on the joints, both knee and hip are recruited into the basic ~Clarity~ System as leverage and target respectively. Since most people look for greater hip extension, this action (Hip Extension) often serves as the target.
Frequently beginner Zaichik Stretching practitioners assume that they are progressing, since the hip extends deeper into the target. In some cases, it is not the case. The hip does extend, but the muscle does not lengthen. This has to do with two other actions of the Rectus Femoris on the hip joint. One being the lateral rotation and the other abduction. In standard side position, rising of the knee shortens the muscle through both of these actions. For this reason, while the hip extends, the shortening of the muscle happens through other actions of the hip joint. This is seen as the knee rising due to abduction and lateral rotation of the hip joint.
Summary: In short, to make sure that you are stretching Rectus Femoris, keep the knee leveled as the hip extends.
You can find the ~Clarity~ System together with 5 other Zaichik Stretching Techniques (ZST) and Supporting Exercises in Hip Flexors Flexibility Progam!