Tight hamstrings are a common complaint for lots of runners. Here's a great warmup exercise to stretch your hamstrings before a run!

• Lie down on the ground on your back.
• Bend one of your knees so that your foot touches the floor.
• Lift your other leg up straight up in the air.
• Loop a towel around the arch of the lifted foot, then gently pull on the towel while your foot pushes the towel up gently.
• Make sure to push to the point where your muscles contract.
• Repeat the same process with your other leg. Hold for 5 to 10 seconds.
• Repeat for 1 to 3 times for each leg.

Doing a stretch exercise like this loosens your hamstrings, lessening the chances of cramps or injury.