This tough mountain climber variation "will challenge your upper-body strength while working your quads and targeting your abs," said Jenn Cino, NASM-certified personal trainer. "Your heart rate will be up in no time." You can use sliders or substitute towels, washcloths, or paper plates.
- With the towels under your feet (if you are on a hard floor; use paper plates if you are on carpet), start in a basic, straight-arm plank position.
- Then, as if you were actually running, pull one knee toward your chest, dragging your foot on your "slider" along the floor. As you push that leg back, pull the other knee forward quickly, like you're running or "climbing" in place.
- This completes one rep.
