4. Medicine Ball Hamstrings
Like the name suggests, this works on your hamstrings. Lie down on the floor, bend your knees at a 90 degree angle and keep your toes on the top most part of the medicine ball, without having to lift your body up. Now slowly push your hips up in the air using force from your hamstrings so that only the tip of your toes is touching the ball; then return to starting position. You will have to continuously maintain your balance with the medicine ball and at no time should you lift your toes completely off the ball. Do two sets of 8-12 reps each.