|This is a great exercise for VMO, glute max and gluteus medius strengthening which is important for hip, knee and pelvis stability. It's effectively a one legged squat, but you step down and back, making sure you bend a the hip and keep the pelvis level.|
Stand on one leg and keep your opposite hip higher. Slowly step backwards and downwards, bending at the hip and knee together. Don't let your knee roll in or opposite hip drop down. Focus on knee alignment. Keep your front shin and spine all the same forward angle (30-40deg) and imagine sitting back down on a box. Let your back leg go backwards and shoulders come forwards, and don't bend more at the knee that you do at the hip.
Use a band and BOSU to advance this exercise