Stand and take one big step forward. Keep your body upright and slowly bend your front knee to lower yourself down toward the ground. Bend your back knee also as you lower your body until both knees are at 90-degree angles. Don’t let your back knee touch the ground. Press your front heel into the ground, straighten your knees, and rise up. As you rise, bring your back leg forward and step into the next lunge. Keep your knees in line with your feet. When in the lunge position, your front knee should not extend beyond your toes.
Make sure to talk with your doctor before starting any new fitness routine.