Mountain climbers

Muscles worked

How to do it

1. Start in a high plank, hands under the shoulders.
2. Drive one knee toward the chest.
3. Switch legs quickly, like running in place.
4. Keep the hips level and the back flat.

Common mistakes

• The hips bouncing up — keep them in line with the shoulders.
• Hands drifting forward — keep them under the shoulders.
• Speed over form — slow down if the plank breaks.

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