Stand with your feet together. Take a controlled lunge (or large step) backward with your left foot.
As you lunge back with your left foot, drive your left arm forward to maintain your balance.
Lower your hips so that your right thigh (front leg) becomes parallel to the floor and your right knee is positioned directly over your ankle. Keep your left knee bent at a 90-degree angle and pointing toward the floor. Your left heel should be lifted. This is your starting position.
From the ground, shift your weight to your right foot, and push through your right foot as you jump up with your left leg lifted at a 90-degree angle and as high as you can with control. Simultaneously drive your right arm up to maintain your balance and proper form.
With control, lower down to the starting position.
This is considered one rep. Be sure to complete this exercise for the desired amount of reps on each leg.