Make Any Exercise Harder

If you want  to make an exercise harder, add weight. If you want to make your whole body work harder while performing an exercise, change your stance. "Altering the way you place your feet on the ground forces you to use more stabilizing muscles, which compounds the challenge of the move,"says Bruce Mack, co-founder of Thrive Training Systems.

Working your stabilizing muscles strengthens your core, which will help you move heavier loads in the future, Mack says. He suggests advancing your stance for standard exercises like the biceps curl. While foot placement won't increase the stress on your biceps, stabilizing yourself will strengthen muscles in addition to those in your arms. The result: a bigger calorie burn and a greater total body strength-building effect.