Mountain Climbers

• Full body
• Intermediate
• Timed — 30 seconds per set

Mountain climbers are a moving plank: knees drive toward the chest one at a time while the core keeps the hips level.

It doubles as cardio — the faster the tempo, the higher the heart rate — but the plank underneath is the point. If the hips bounce or pike, slow down until they stay level; speed you cannot control is wasted.

How to do it

1. Start in a high plank with hands under shoulders.
2. Drive one knee toward your chest, then switch quickly.
3. Keep your hips low and core tight.

Breathing: Quick, rhythmic breaths.

Common mistakes

• Letting the hips sink toward the floor as the switches get tired.
• Rocking the shoulders forward and back over the hands with every switch.
• Letting the elbows bend so each knee drive turns into a half push-up.

Form tips

• Keep your hips level with your shoulders; piking up shortens every knee drive.
• Stack your hands under your shoulders and keep them there as the legs switch.
• Land on the ball of the foot lightly instead of stamping the floor.

Muscles worked

Alternatives with the same focus

• Plank Jacks
• Skaters
• Star Jumps

Where it appears in the 30-day plan

Programs in the app that schedule this movement:

• Core & Abs
• Lower Belly
• Love Handles
• Upper Abs