Come onto your hands and knees with your shoulders directly over your wrists and your knees underneath your hips. Place the foam roller horizontally across your lower back to help you find a neutral spine.
Keeping your torso stable, extend your right arm out in front of you and extend your left leg behind you. Try to avoid shifting to the side as you do this (you will feel the foam roller shift on your back if you're shifting your bodyweight).
Hold for one to three seconds, then return to the starting position. Repeat on the opposite side.
This completes one rep.
Perform three sets of 24 reps, followed by a 30- to 60-second rest.