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The HIT MethodAn independent guide to high-intensity training

Cross Jack: How to Do It, Muscles Worked and Easier Options

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The cross jack, sometimes called crisscross jacks, is a beginner high impact exercise requiring no equipment. It modifies the traditional jumping jack by having you cross your arms and legs in front of your body on the inward jump. This movement pattern works your hip adductors, hip abductors, and calves, while your shoulders act as supporting muscles.

Adding this move to your routine helps build lower body coordination and lateral agility. Because it requires rapid changes in foot position, it demands focus to maintain a steady rhythm during intense intervals.

Exercise data

Impact
High
Level
Beginner
Equipment
None
Main muscles
hip adductors, hip abductors, calves
Also working
shoulders
Movement
Jumping the feet out and crossing them as you land in
Low-impact swap
alternating crossover steps

How to do a cross jack

Stand tall with your feet shoulder-width apart and your arms extended straight out to your sides.

  1. Jump up slightly to bring your feet together, crossing your right foot in front of your left.
  2. At the same time, cross your right arm over your left arm in front of your chest.
  3. Jump again to return your feet to a shoulder-width stance while opening your arms back out to your sides.
  4. Jump a third time, now crossing your left foot in front of your right and your left arm over your right arm.
  5. Jump back to the wide starting position.
  6. Continue alternating which arm and leg cross in front for the duration of your set.

Form cues

  • Stay light on the balls of your feet.
  • Keep your knees slightly bent during landings.
  • Maintain a braced core and an upright chest.
  • Coordinate your arm and leg crosses simultaneously.

Common mistakes

  • Stiff knees. Keep a soft bend in your knees to absorb the high impact of the jumps and protect your joints.
  • Dropping the chest. Look straight ahead and keep your torso upright rather than hunching forward as you cross your arms.
  • Flat feet. Land softly on the balls of your feet to engage your calves and prepare for the next jump.
  • Shortchanging the arm movement. Open your arms fully to the sides on the outward jump to properly engage your shoulders.
  • Forgetting to alternate. Focus on switching the front leg and arm on every inward jump to work your hip adductors and abductors evenly.

Easier and harder versions

Easier

  • alternating crossover steps

Harder

  • Increase your jumping pace to complete more repetitions in the same amount of time.
  • Sink into a deeper quarter-squat position on the wide outward jump.

Using it in intervals

When using the cross jack in your high-intensity intervals, aim for a fast, consistent pace that pushes your breathing rate up. Because footwork gets sloppy as fatigue sets in, you must focus heavily on your coordination during the final seconds of a work period. If you find yourself tripping over your feet, slow your rhythm down slightly rather than stopping entirely. Prioritize a soft landing on every single rep to manage the high impact.

Formats that suit this move: Tabata Workout, 30/30 Intervals.

Impact note. This move involves jumping. If impact bothers your knees, ankles, back or pelvic floor, use the low-impact swap: alternating crossover steps.

Similar moves

When to stop and see a doctor

  • Sharp pain in your knees or ankles during the landing phase.
  • A popping sensation in your calf muscles.
  • Pinching or deep aching in your hip joints.
  • Dizziness or lightheadedness.

This page is general information, not medical advice. If you have a heart condition, high blood pressure, joint problems, are pregnant or have been inactive for a long time, talk to your doctor before starting vigorous exercise.

How this page was made. Exercise data (impact, level, equipment, muscles) was compiled by our editors as a general anatomy and coaching guide. Text drafted with AI assistance and checked by the Training Desk; see how we write. Last checked October 2026.