Hip Snap/Hip Vibration
Hip snap occurs as the hip of side executing the technique snaps toward the target and then recovers. This occurs as the hips are relaxed, snapped into the technique, tensed on impact, and then relaxed as allowed to return to the normal position. Sometimes there is a cocking of the hip before it snaps.
Hip vibration is a term used to describe the movement of the hip during hip snap. The hip cocks, snaps forward, and recoils in short quick vibrating motion. The recoil part of the vibration serves as a counter balancing motion, helping you maintain balance without shifting the center of mass in the direction of the strike. Hip vibration is subtle movement that takes hours and hours of training to perfect. The most common errors in the use of hip vibration are throwing the shoulders forward, not coordinating the timing of the hips and hands, and moving the hips too slowly.