REVERSE 

PLANK REPS

Lay on you back with on your elbows, keeping them directly underneath your shoulders. Straighten your legs out in front of you so that your body is in a straight line. Pinch your shoulder blades together and begin to squeeze your glutes, lifting your hips off the floor. Drop your head back if you feel tension in your neck. Hold for a full exhale and lower back down to the ground in the starting position. Repeat.