Single arm push-up

Start in a push-up position with your hands shoulder-width apart and one hand placed slightly wider than the other. Engage your core and lower your body towards the ground by bending your elbows, keeping your back straight. As you lower yourself, shift your weight to one side and lift the opposite arm off the ground, extending it straight out to the side. Push through your chest and triceps to raise your body back up to the starting position, while simultaneously lowering your extended arm back to the ground. Repeat the movement, alternating the arm you extend with each repetition.