This lunge variation targets the deep hip flexors, found at the front of the hip, that definitely get worked when running — especially sprints.
Begin in a runner's lunge, and place your right hand on the outside of your right foot. Reach your left hand to the ceiling, increasing the stretch on the left side of the body. Hold for 10 to 15 seconds.
Then place the left hand at the inside of your right foot. Twist to the right and reach your right arm to the ceiling. Hold this position for 10 to 15 seconds.
Repeat this sequence on the other side. Feel free to do this stretch two to three times on each side.