The step for this exercise should ideally be 10 to 15 cm high (one in the video is 11 cm). Note that the focus is on your stance leg, not your stepping leg. Make sure your toes do NOT extend over the edge. Also, make sure your knee is steady and is not moving from side to side. Keep your hands on your hips. IMPORTANT: Do not transfer your weight to the stepping leg. Touch down with your heel and immediately bring it back up. Straighten the stance leg slowly when you bring it back – must take about 3 seconds to straighten. Do 3 sets of 10 repetitions for each leg.