Stability ball hamstring curl with bridge
To challenge your hamstrings and your glutes, lie on your back with your feet on a stability ball and your hands on the floor for support. Lift your hips off the ground, and then use your hamstrings to draw the ball toward your body. Bend your knees as you pull it close. When your knees are bent and pointing toward the ceiling, lift your hips until your body forms a straight line from your knees to your shoulders. Lower your hips and roll the ball back to start. Repeat eight to 12 times.
Photo Credit: Girls Gone Sporty