Begin on all fours with your shoulders stacked above your wrists and your hips stacked above your knees.
Engage your core by drawing your belly button into your spine.
Keeping your right knee bent at a 90-degree angle and your foot flexed, squeeze your glutes to lift your leg up behind you until your thigh is parallel with the ground. (Imagine you're making an imprint of your foot on the ceiling!)
Be sure that your torso remains squared to the ground.
Slowly return to the starting position and repeat for 30 seconds without resting your knee on the ground between reps. Repeat for 30 seconds before switching sides.