Elevated Mountain Climbers
Like traditional mountain climbers, this slower, more deliberate modification will not only boost your heart rate, but tax your shoulder stability and core strength, too. Start in a plank position with your hands directly under your shoulders and the tops of your feet resting on the chair’s seat. With a flat back and tight core, draw one knee toward your chest so that you’re balancing on your hands and one foot. Return the foot to the chair and repeat the movement with the other leg. Be careful not to let the hips pike or sag.
Alternating legs, do three sets of 12 reps on each side.