Come into an all fours position, with your hands underneath your shoulders, knees underneath your hips. Keep a neutral spine, so you’re in tabletop position with your back.
Engage the core by drawing that belly button into the spine
Begin by lifting and extending the opposite arm and leg. You want to be reaching out as long as you can and really pull from those limbs. The foot can either be flexed or pointed.
When you reach full extension, hold and squeeze the glutes and core.
Return back to the starting position and repeat on the opposite side.

Move of the week: try holding a bird dog if you want to build serious core stability