HOW: Begin by lying on a foam roller. Your head, back and hips should all be centered on the roller. Bend your knees and place your feet flat on the floor with your hands out slightly from the roller for support. Move one hand up and over diagonally as you kick the opposite side leg out diagonally. Then, bring your knee up and the hand down to meet in the middle. Repeat for as many reps as prescribed.
FEEL: You should feel your core muscles working to stabilize yourself on the ball..
COMPENSATION: Stay centered on the foam roller. Move the hand and knee in a diagonal direction.