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  5. Chest
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  7. Exercise Ball Alternating Arm Ups

Exercise guide

Exercise Ball Alternating Arm Ups

  • Intermediate
  • Compound
  • Rep-based
  • Back
  • Chest
  • Shoulders
  • Waist

This exercise develops core stability and shoulder control by forcing the obliques and abdominals to stabilize the torso against unilateral movement on an unstable surface. It specifically targets the deltoids and trapezius while improving postural alignment and balance.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Exercise Ball Alternating Arm Ups demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Abs
  • Deltoids
  • Obliques

Secondary

  • Serratus anterior

Equipment

  • Stability ball

Setup

  1. Sit upright on the center of a stability ball with your feet flat on the floor, hip-width apart.
  2. Engage your core and maintain a neutral spine with your shoulders rolled back and down.
  3. Position your arms straight down at your sides with your palms facing your body.

How to do it

  1. Exhale as you slowly raise one arm straight up in front of you until it is aligned with your ear, keeping the elbow locked.
  2. Maintain a perfectly still torso, resisting the urge to lean back or shift your weight on the ball.
  3. Inhale as you lower the arm back to the starting position with a controlled 2-second tempo.
  4. Repeat the movement with the opposite arm, alternating sides for the duration of the set.

Form checklist

  • Keep your chest lifted and avoid rounding your lower back or shoulders.
  • Ensure the stability ball remains completely stationary throughout the movement.
  • Avoid shrugging your shoulder toward your ear as you lift your arm.
  • Keep your feet firmly planted and avoid using them to 'grip' the floor for balance.

Pro tips

  • Focus on 'bracing' your midsection as if preparing for impact to maximize the engagement of the obliques and transverse abdominis.
  • Pause for one second at the top of the movement to emphasize the isometric contraction of the deltoid and upper trap.

Make it harder

  • Bring your feet closer together or touch them to create a narrower, more unstable base of support.
  • Hold a light dumbbell or weighted ball in each hand to increase the resistance on the shoulders and the demand on the core.

Frequently asked

What muscles does the exercise ball alternating arm ups work?
The exercise ball alternating arm ups primarily targets the abs, deltoids, and obliques, and also works the serratus anterior as secondary muscles.
What equipment do you need for the exercise ball alternating arm ups?
The exercise ball alternating arm ups uses stability ball.
Is the exercise ball alternating arm ups good for beginners?
The exercise ball alternating arm ups is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.

Related exercises

  • Forearms Plank With Shoulder ProtractionIntermediate · abs, deltoids, and obliques
  • Front Plank With TwistIntermediate · abs, deltoids, glutes, and obliques
  • Incline Jack PlankIntermediate · abs, deltoids, obliques, and pectorals
  • Jumping Air Bike Arm SwingIntermediate · abs, calves, deltoids, and obliques

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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