How to do it: Start on all fours. Reach your right arm forward while simultaneously stretching your left leg back and flexing your foot. Hold for 5 seconds, then release both your arm and opposite leg. Repeat using the left arm and right leg. That's one rep. Do 10 to 15 reps.
Trainer tip: Make sure to keep your back, arms, and legs straight.
Try this move: Opposite arm and leg reach