HOW: Start in a half-kneeling position. The goal of this exercise is to work the kneeling leg. Keep your toes pointing into the ground. Keeping as much weight as you can on your back leg, drive your toes into the ground and try and lift your back knee about a ½ inch off the ground. Hold for the prescribed amount of time.
FEEL: You should feel the quadriceps muscle of your down knee holding your body up.
COMPENSATION: Do not lean forward and shift the weight to your front leg. Try to use your back leg as much as possible to achieve the lift-off.