By placing a ball between your calf and hamstrings on one leg and squeezing in, you’ll fire up and strengthen your hamstrings muscles. Lifting your leg will get your glutes and lower back in on the action. Plus, your position on all 4s will make you feel supported through your core as you tone those hams, buns, and back.
The bigger the ball, the easier it will be to embrace. So, it’s a good idea to begin with a bouncy ball (like the ones you find in big metal racks at discount stores), then progress to something a tad smaller, like a Bender Ball (Buy now: $13, amazon.com), and eventually use something quite compact, like a SandBell (Buy now: $19.99, amazon.com). Although a smaller tool will work your hamstrings the best, stick with a bigger ball if the deeper flexion at your knee causes discomfort.
Step 1: Assume “all 4s” position with your knees hip-width apart and hands planted directly beneath your shoulders. Place the ball behind your knee on one leg and squeeze in with your lower leg to hold it securely.
Step 2: Lift your thigh to the height that matches your torso (see Trainer Tip below). Stop the movement at this point, then slowly return the knee to the ground. This move should be performed with control: Take two full seconds to lift and two full seconds to lower.
Complete 15 repetitions on one leg before moving the ball to the other leg for 15 repetitions.
Trainer Tip: Lifting the thigh any higher than parallel to the ground may exceed your lower back strength and cause discomfort. Avoid excessive back hyperextension by stopping at torso height, as shown in Step 2. This one move will strengthen your hamstrings, glutes and also your lower back.