A key factor in fast Free and Backstroke swimming is hip rotation. Swimmers who have not yet mastered the proper use of their hips when swimming Free and Backstroke tend to under rotate, over rotate, or rotate at the wrong time. The Hydro Hip can greatly assist a swimmer’s timing of the rotation of the hips, arms, and body. If a swimmer has delayed rotation, his or her arm will be pulling towards the hip while the blades are still at surface level, causing a collision with the blades. The blades also provide water resistance, which helps train and build the swimmer’s awareness of the use of his or her core strength.