This is a great single leg exercise that will strengthen your quads, hamstrings and glutes. Begin with your weaker leg placed squarely on a stable box or bench. Your weight should be on the heel of your elevated foot to keep the stress off of your knee. With little help from your back leg, step up onto the box. Make sure your lower back does not round and your head and eyes are forward. This exercise can be done with a barbell, dumbbells, or a weighted vest.