This exercise may require more effort than the others on this list, but the results are worth the pain. "Mountain climbers are sure to get your heart pumping and work your core, shoulders, and legs," Kendall said.
- Start in a traditional plank position with all your weight on your hands and toes.
- Bring your left knee forward, tucking it under your chest. Return to the start position and then perform the same movement with the other leg.
- Keep switching legs, picking up your speed to do this with some intensity.