Half jacks

Muscles worked

You need

How to do it

1. Stand with your feet together and your arms relaxed by your sides.
2. Jump your feet out wide, then jump them back together, in a continuous rhythm - it's the leg half of a jumping jack, with your arms staying low and loose instead of swinging overhead.
3. Land softly on the balls of your feet with your knees bending to absorb each landing, and keep your torso tall throughout.