HOW: Get set-up balancing on one foot on an elevated surface. Begin the exercise by reaching forward with the foot that is in the air and letting your hip and knee bend with your knee moving forward over your foot. Just tap the ground if you can, then return to starting position, then reach backwards with the same foot in the air by letting your hip bend and torso lean forward. Just tap the ground if you can, return to starting position and repeat.
FEEL: On the working leg, you will feel your quads and calfs working when you reach forward vs. your glutes more when you reach backwards. However, your entire leg will be getting a workout.
COMPENSATION: Do not put all of your weight down on the ground with the leg you're reaching with, just think of tapping an eggshell. Focus on good torso and knee position the entire time, do not let your knee cave in/out, keep your pelvis level to the ground, maintain good balance.