If you have knee problems, you can double up on your mat for more support (or skip this exercise altogether).
Keeping a proper squat stance, start kneeling one leg at a time. Don't let your knees go over your toes; shift your knees back to you can lift your toes off the ground.
Step up, one leg at a time, keeping your legs parallel and staying in that low squat position.
Repeat eight times.