More ideas from Ren
Find yourself a wall to test out this 'Pumped-Up Plank', which works shoulders, abs, obliques, and lower back! #SelfMagazine

The No-Equipment Workout: Pumped-up Plank. Start in plank, hands under shoulders, feet in line with hips and pressing into wall (as shown). Hold for 1 minute. Make it easier: Lower legs, place toes on floor with feet pressed against wall.