How to do: Ball Crunches

Start seated on a stability ball with your feet flat on the floor. Roll yourself down so that your lower back is supported by the curve of the ball. Move your feet so that they are directly underneath your knees and hip-width apart. Place your hands behind your head or across your chest. Slowly lower down and back up, crunching your abs. Keep your hips tucked and glutes squeezed as you contract your abs.

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