The single knee-to-chest exercise stretches the muscles in your buttocks.

Here's how to do it.

Start by lying on your back with your knees bent and your feet flat on the floor.

Next, clasp your hands around one knee and bring that knee up toward your chest.

Hold that knee to your chest, keeping your lower back pressed to the floor, for 15 to 30 seconds.

Now relax and lower your knee back to the starting position.

Switch knees and do it again.

Do this exercise 2 to 4 times with each leg.

If you have knee pain, you can clasp your hands behind the thigh instead of around the knee.

If you want to get more stretch out of this exercise, or if it feels better on your back, try keeping your opposite leg flat on the floor as you bring your knee up.

Remember, if an exercise makes you feel worse, stop doing it.