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  3. Exercises
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  5. Core & Abs
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  7. Spell Caster

Exercise guide

Spell Caster

  • Intermediate
  • Compound
  • Rep-based
  • Core

The Spell Caster is a dynamic rotational exercise that builds explosive core strength and shoulder stability by forcing the obliques to accelerate and decelerate weight across the transverse plane.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Spell Caster demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Abs
  • Deltoids
  • Obliques

Secondary

  • Lats
  • Pectorals
  • Serratus anterior

Equipment

  • Dumbbell

Setup

  1. Stand with your feet slightly wider than shoulder-width apart for a stable base.
  2. Hold a light dumbbell in each hand with your arms extended down at your sides.
  3. Engage your core and maintain a slight bend in your knees to protect your lower back.
  4. Rotate your torso slightly to bring both dumbbells toward the outside of one hip.

How to do it

  1. Swing the dumbbells diagonally across your body and upward toward the opposite shoulder in a smooth, 'casting' arc.
  2. Exhale forcefully as you drive the weights upward, using your obliques to power the rotation.
  3. Inhale as you control the descent, bringing the weights back down across your body to the starting hip.
  4. Alternate sides by swinging the weights to the opposite hip and repeating the diagonal upward arc.

Form checklist

  • Keep your arms mostly straight with a soft micro-bend in the elbows.
  • Pivot your trailing foot slightly to allow your hips to rotate safely with your torso.
  • Maintain a proud chest and avoid rounding your shoulders forward during the swing.
  • Use your core to 'brake' the movement at the top and bottom of the arc rather than relying on momentum.

Pro tips

  • Focus on the mind-muscle connection with your serratus anterior and obliques to stabilize the weights at the peak of the movement.
  • Imagine you are drawing a large 'X' in the air with the dumbbells to ensure a full range of rotational motion.

Make it harder

  • Increase the tempo of the 'cast' phase while significantly slowing down the eccentric lowering phase.
  • Pause for two seconds at the top of the arc to challenge your anti-rotational stability.

Frequently asked

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

Related exercises

  • Dumbbell Side Plank RaiseIntermediate · abs, deltoids, and obliques
  • Dumbbell Side Plank With Rear FlyIntermediate · abs, deltoids, lats, and obliques
  • Dumbbell Side Plank RowIntermediate · abs, glutes, lats, obliques, and trapezius
  • Dumbbell Twisting Crunch Legs On BenchIntermediate · abs 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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