Come into an all fours position on an exercise mat with your hands directly under your shoulders, your knees directly under your hips and a short band just above your knees. Keeping your core braced and a flat back, drive your left knee directly out to the side, resisting against the band. Exhale as you do so. When your knee is roughly level with your hips, pause for a count of one and squeeze your glutes. Be sure not to let your weight or hips shift too much to one side as you elevate the knee. With control return to the start position. Repeat all the required reps (or time) on one leg before changing to the other.