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  3. Exercises
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  5. Shoulders
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  7. Stepjack Inner Biceps Curl

Exercise guide

Stepjack Inner Biceps Curl

  • Beginner
  • Isolation
  • Rep-based
  • Shoulders
  • Upper arms

This low-impact compound exercise combines lateral lower-body movement with dynamic tension in the arms, effectively targeting the inner bicep head while engaging the glutes and calves for a full-body burn.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Stepjack Inner Biceps Curl demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Biceps

Secondary

  • Forearms

Equipment

  • Body weight

Setup

  1. Stand upright with your feet together and your core engaged.
  2. Position your arms at your sides with your palms facing forward and slightly rotated outward.
  3. Keep your shoulders back and down, maintaining a proud chest.

How to do it

  1. Step your right foot out to the side while simultaneously curling both hands toward your shoulders.
  2. Exhale and squeeze your biceps at the top of the movement, focusing on rotating your pinkies toward your shoulders to target the inner bicep.
  3. Inhale as you step your right foot back to the center and lower your arms with control.
  4. Repeat the movement by stepping out with your left foot, alternating sides for the duration of the set.

Form checklist

  • Keep your elbows pinned to your ribcage to isolate the biceps.
  • Maintain a slight bend in your knees throughout the step to protect your joints.
  • Ensure your palms remain supinated (facing up) throughout the curl.
  • Keep your torso upright and avoid leaning side-to-side as you step.

Pro tips

  • Use 'dynamic tension' by imagining you are pulling against heavy resistance to maximize bicep fiber recruitment without weights.
  • Focus on the mind-muscle connection by squeezing the biceps hard at the peak of the contraction.

Make it harder

  • Transition from a side step to a deep lateral lunge to increase glute and quad activation.
  • Increase the tempo to turn the movement into a high-intensity cardiovascular challenge.

Frequently asked

What muscles does the stepjack inner biceps curl work?
The stepjack inner biceps curl primarily targets the biceps, and also works the forearms as secondary muscles.
What equipment do you need for the stepjack inner biceps curl?
The stepjack inner biceps curl requires no equipment — just your body weight.
Is the stepjack inner biceps curl good for beginners?
Yes. The stepjack inner biceps curl is a beginner-friendly movement and a strong foundation to build on.

Related exercises

  • Arm Double CrossoverIntermediate · biceps, deltoids, and triceps
  • Arms Stretch On A SupportBeginner · biceps, deltoids, and pectorals
  • Band 45 Degrees Biceps CurlBeginner · biceps
  • Band 45 Degrees One Arm Biceps CurlBeginner · biceps

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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