Start on your hands and knees with your shoulders directly over wrists and your hips over your knees. Pull your abs in toward your spine, making sure your back is flat and your neck is in line with your spine.
Lift your right hand and left leg off the ground. Extend your right hand forward as your reach your left leg back, extending both as far as you can. Keep your core pulled toward your spine and your back straight, making sure not to arch your spine.
With control, lower your right hand and left leg back to the starting position.
This counts as one rep. Do three sets of 10 reps, alternating sides. Rest for 30 seconds between sets.