STEPS FOR MANKIND
Tack this exercise onto the end of any typical cardiovascular routine to increase muscle endurance. Start with three minutes; increase by minute intervals over several workouts.

Stand sideways to a low step (4 inches high, max), keep your knees slightly bent, and start stepping up and down, without using your arms to aid momentum.

After a minute or so, add a little hop up as soon as you hit the ground. Knock off another minute of the drill, trying not to use your arms (put your hands on your waist if you have to).

Aim for at least 30 seconds of full-throttle explosions up to the top of the step, using only the power of your hips and legs. Catch your breath and repeat on the other side.