Hi, I'm CarolAnn with Cyberworkouts.com, and I'm going to show you hamstring stretches and strengthening exercises, and the one great tool that I like to use is a stability ball. So, come on down to the floor. The first thing we're going to do is a hamstring strengthening exercise, and this is a one-legged circle. So, you've got both legs on top of the ball, and then you want to lift one up in the air while lifting your hips up off the floor. Now, immediately you feel your hamstring engage, and this is a great isometric contraction. Then you're going to circle that leg around and up, and really bearing down on your abdominal muscles, keep your shoulder blades anchored, and you can do about 10 circles in one direction, 10 circles in the opposite direction. Now, as the leg that's on the ball is strengthening, the leg that's up in the air is stretching. So, we've got a really great exercise here combining both strengthening and stretching. The next hamstring strengthening exercise you can perform is a hamstring curl with the ball. So, your hips are up and you're going to gently pull the ball in towards your glutes and extend out, pull in and extend out. And this is very intense, so try to get to 20 reps of the hamstring curl. Then, when you're finished, you can gently just lower your hips down towards the floor and gently extend the leg and pull the leg towards your chest, and this is a great hamstring stretch. Anytime you're holding a stretch, you want to hold anywhere between 20 to 30 seconds, and then switch sides. So, anytime you strengthen your muscles, you have to stretch. And again, hold for 20 to 30 seconds. And those are some great hamstring stretches and strengthening exercises. I'm CarolAnn for Cyberworkouts.com.