This exercise is designed to improve strength throughout your hip extensors (gluteals).
Start on your back with your knees bent, feet away from your buttocks and toes spread. Lengthen your lower back, contract your buttock muscles (glutes) and lift your hips. Be sure to press through your whole foot and avoid arching your lower back.
Hold your hips up while contracting your glutes for 30 seconds. Repeat 3-5 times.