Standing Leg Extension: Aim to have it resting above your ankle. Stand hip-width apart. Shift your weight to your left foot and pick up your right foot, keeping your right leg straight. Raise your right leg up and to the side until you really feel the band pulling against your leg. Slowly lower your leg back to your left foot, but do NOT set it down. That is one rep. Do as many as you can for 30 seconds, then switch legs
Knee Squats to strengthen Hip Flexors and Glutes. I was a skeptic too until I tried it and yes, they work! The stronger your Hip Flexors, the faster you can run and the more powerful you are in many exercises.