Starting position: Stand with feet hip-width apart. In this position, gently contract your abdominal / core muscles ("bracing") to stiffen your torso and stabilize your spine. Depress and retract your scapulae (pull your shoulders down and back) without arching your low back while keeping your arms hanging comfortably along your side.
Keep the right foot planted on the ground, (maintain balance through the movement by pressing the right foot into the ground while extending the leg and squeezing (contracting) both the thigh and glute muscles), lift the left knee so that it is straight in front of the hip and the hip is at a ninety degree angle. Bend the arms at ninety degree angles, as you raise the left knee, swing the right arm forward to flex the right shoulder while swinging left arm back to create shoulder extension.
Maintain the abdominal bracing to keep the core stiff and the spine straight, lean forward on the right hip while simultaneously extending the left hip behind your body, at the same time reach forward with the right arm to create right shoulder flexion and move the left elbow back to create left shoulder extension. Keep the right foot firmly planted into the ground to maintain balance and stability.
Continue flexing forward on the right hip (continue squeezing the right thigh and glutes to help maintain stability) while reaching forward with the left arm and extending the right leg backwards (into hip extension). To help maintain balance, find a spot on the floor and fix your gaze on that spot, this will create additional stability.
At the point where you feel your end range-of-motion while balanced on your right leg, reach forward with the left arm to fully extend the elbow while flexing the shoulder at the same time extend the left leg straight back to create full hip extension. Point the toes of the left foot towards the wall behind you in order to move into full extension of the left hip (and concurrent flexion of the right hip); continue to maintain abdominal bracing to ensure balance and stability. Try to keep the hips level and do not let the left hip drop towards the floor or roll away from the right (planted) leg. Hold this position for 3-5 seconds.
Maintain abdominal bracing and begin to lean back into the right hip while pulling the left hip forward (back into flexion) and the left arm back down towards your midsection. Return to an upright, standing position and repeat for a specific number of repetitions or a certain period of time. Alternate legs and repeat for the same number of repetitions or period of time.
Exercise Variation: To add resistance and increase the level of difficulty, hold a dumbbell in your left hand (the weight should be in the hand opposite of the standing (balance) leg).
If balancing on the right leg, use the left leg to help move into a position of flexion on the right hip; pointing the left leg backwards while pointing the toes and straightening the legs will help move the right hip into a position of flexion.