Sitting toward the edge of a chair with good posture and bent knees, hold on to the sides of the chair with your hands. Extend the right knee out so that the toes come up toward the ceiling, being sure to keep the knee slightly bent without
locking it through the entire movement. Lower the leg back to a bent position and repeat this movement 8 to 10 times, using about 2 seconds each to lift and lower the leg. Switch to the opposite leg and perform 8 to 10 repetitions. Rest briefly. Do another set of 8 to 10 repetitions for each leg.
Modification: If you are more advances, sitting in the same position as above extend one leg out in front of you with toes pointed to the ceiling. Lift and lower the entire leg only as high as you comfortably can, keeping the knee slightly bent.