Mountain climber

From a high plank, drive your knees toward your chest in quick alternation for cardio plus core and shoulder work.

How to do it

1. 01Start in a high plank with your hands under your shoulders and body straight from head to heels.
2. 02Drive one knee toward your chest, keeping your hips low and shoulders over your hands.
3. 03Switch legs, sending that foot back as the other knee comes in — keep alternating.
4. 04Keep your core tight and a fast but controlled pace for the full interval, breathing steadily.

Common mistakes

• Piking the hips up — keep them low and level with your shoulders.
• Shoulders drifting behind the wrists — keep them stacked over your hands.
• Torso rocking side to side — brace so only your legs move.

In the Conditioning progression

1. 1Step jack
2. 2Jumping jack
3. 3High knees
4. 4Mountain climber
5. 5Burpee (no push-up)
6. 6Burpee