Jumping jacks form: arms all the way up and down

Jumping jacks are meant to be quick, so GymSensei doesn't flag fast reps here. It does check that your arms go all the way up and come all the way back down.

How to do it

1. Stand with your feet together and your arms by your sides.
2. Jump your feet out wide as your arms swing up over your head.
3. Jump back to the start with your arms back down.
4. Keep a steady rhythm and land softly.

What counts as a full rep

Your arms have to swing from about 50° to 150° from your sides, so your hands end up above your head, and then come back down.

What the camera calls out

You hear a short cue mid-set when something's off. After the set, the report card gives you one line on whichever fault came up most.

Setting up your phone

Face the phone, about 3 steps back, with the phone at waist height so your hands fit when they're up.

Start with your feet together and arms down.

Muscles worked

Mostly your legs, with your calves, glutes and shoulders helping.

Exercises this check works on

• Jumping jacks
• Star jumps

A tip from the coach

If jumping bothers your knees, step one foot out at a time instead. Your arms still go all the way up.

Other exercises

• Squat
• Push-up
• Lunge
• Romanian deadlift
• Overhead press
• Biceps curl
• Plank
• Glute bridge
• Sit-up
• Lying leg raise
• Lateral raise
• Bent-over row
• Pull-up
• Wall sit
• Side plank

Updated 11 October 2026. General fitness and nutrition guidance, not medical advice.