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  3. Exercises
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  5. Shoulders
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  7. Step Jack

Exercise guide

Step Jack

  • Beginner
  • Compound
  • Timed hold
  • Lower legs
  • Shoulders
  • Upper legs

The Step Jack is a low-impact, cardiovascular exercise that targets the lower body and shoulders, using a step to enhance glute and quad activation while minimizing joint stress compared to traditional jumping jacks.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Step Jack demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Calves
  • Obliques
  • Quadriceps

Secondary

  • Abs
  • Serratus anterior

Equipment

  • Body weight

Setup

  1. Stand upright facing the long side of the step with your feet hip-width apart.
  2. Position your arms at your sides with palms facing inward.
  3. Engage your core and maintain a slight bend in your knees.

How to do it

  1. Step one foot laterally onto the center of the step while simultaneously swinging both arms out and up overhead.
  2. Exhale as you reach the top of the movement, ensuring your arms form a wide 'V' or touch briefly.
  3. Step the foot back down to the starting position while lowering your arms back to your sides in a controlled motion.
  4. Immediately repeat the movement by stepping the opposite foot onto the step, alternating sides at a brisk, rhythmic tempo.

Form checklist

  • Plant your entire foot firmly on the step to ensure stability and prevent slipping.
  • Keep your chest lifted and avoid leaning forward as you step up.
  • Ensure your knees track in line with your toes, avoiding any inward collapse.
  • Maintain a tall posture and avoid shrugging your shoulders toward your ears during the arm raise.

Pro tips

  • Drive through the heel of the stepping foot to maximize glute and hamstring recruitment.
  • Focus on a powerful, full range of motion with the arms to increase heart rate and better engage the deltoids and pectorals.
  • Keep your core tight throughout to stabilize the pelvis and engage the obliques during the lateral stepping motion.

Make it harder

  • Increase the height of the step to demand more power and range of motion from the quadriceps and glutes.
  • Hold light dumbbells or wear wrist weights to add resistance to the lateral arm raises.

Frequently asked

What muscles does the step jack work?
The step jack primarily targets the calves, obliques, and quadriceps, and also works the abs and serratus anterior as secondary muscles.
What equipment do you need for the step jack?
The step jack requires no equipment — just your body weight.
Is the step jack good for beginners?
Yes. The step jack is a beginner-friendly movement and a strong foundation to build on.

Related exercises

  • Bosu Ball Step-Up High Knee Air TwistIntermediate · abs, calves, glutes, hamstrings, obliques, and quadriceps
  • Cross Body Punch JackIntermediate · abs, calves, obliques, and quadriceps
  • Plank Walk SquatIntermediate · abs, calves, glutes, hamstrings, obliques, and quadriceps
  • Punch TwistIntermediate · abs, calves, obliques, and quadriceps

Train it with Crucible Fit.

Every movement in this library is in the app with video and instructions, ready for your own sessions on the days between Crucibles. Your first Crucible is on us.

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