Physioball Hamstring Curls

What You'll Need
Grab, well, what do you think you're gonna grab? Having grabbed it, find some floor space and perhaps a mat too?

Why You Should Be Doing This Exercise
This may be the most underrated hamstring exercise you've never heard of. You'll hit your hamstrings almost exclusively, but challenge your hips and back while you're at it. Once you've mastered the movement, you can move on to one-legged sets, but we think two legs will be plenty difficult to do with good form.

Start
Lay down on the floor, on your back, with a ball beneath your calves. Your arms should be by your sides to help you stabilize. Ready? Let's go.

Middle
Raise your hips up off of the floor so that you create a line between your ankles, knees, and shoulders. Now pull your heels back towards your hips. Once the ball has rolled from the back of your foot to touching your toes, breath out, and extend your knees so that the ball rolls back to touching just the back of your feet.

Finish
Keep your hips off of the ground if you feel like going back for more, or drop your hips once you're done with the set.

Key Don'ts
Remember that this is a hamstring exercise, which means squeezing once you've bought your heels to your hips. Remember also to keep your feet on the ball throughout. Finally, remember this isn't a race. This is a hamstring exercise. You do these to run faster in the race, but you don't have to race through them.