Movement: Step backward keeping the shin of your forward leg vertical, and your weight on your front heel. Brace through your stomach and do not allow your lower back to round. Descend until just before your knee touches the floor, then step back to the start position. Perform the desired number of repetitions and repeat with your opposite leg.
Repetitions: Perform all prescribed reps on one side, then on the other. This counts as one set.
Benefits: The reverse lunge tends to put less stress on the knee by keeping the front leg immobile and reducing the risk of that knee coming forward past your toes (which causes more shearing forces).