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  3. Exercises
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  5. Shoulders
  6. /
  7. Side Plank Plus

Exercise guide

Side Plank Plus

  • Intermediate
  • Compound
  • Timed hold
  • Shoulders
  • Waist

The Side Plank Plus enhances the traditional side plank by incorporating active shoulder protraction, significantly increasing engagement of the serratus anterior, obliques, and lateral glutes for superior core stability.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Side Plank Plus demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Abs
  • Deltoids
  • Obliques

Secondary

  • Serratus anterior
  • Trapezius

Equipment

  • Body weight

Setup

  1. Lie on your side with your forearm flat on the floor and your elbow positioned directly underneath your shoulder.
  2. Stack your feet on top of each other or place the top foot in front of the bottom foot for a wider base of support.
  3. Align your head, hips, and heels in a straight line before initiating the lift.

How to do it

  1. Exhale as you lift your hips off the floor until your body forms a straight diagonal line from head to heels.
  2. Perform the 'plus' movement by pushing your bottom elbow forcefully into the floor to protract your shoulder blade and lift your ribcage as high as possible.
  3. Inhale and maintain this active, elevated position while keeping your core braced and glutes squeezed tight.
  4. Hold the position for the prescribed duration, ensuring the shoulder remains active and the hips do not sag.

Form checklist

  • Keep the elbow stacked directly under the shoulder to prevent unnecessary joint stress.
  • Maintain a neutral neck by looking straight ahead rather than down at your feet.
  • Ensure the hips remain stacked vertically and do not rotate toward the floor.
  • Keep the bottom shoulder 'long' by constantly pushing away from the floor.

Pro tips

  • To maximize oblique recruitment, imagine trying to pull your bottom elbow toward your feet without actually moving it.
  • Focus on the 'plus' by feeling the muscles under your armpit (serratus anterior) engage as you push the floor away.

Make it harder

  • Lift the top leg toward the ceiling to create a 'star' position, increasing the load on the lateral glutes.
  • Perform the movement on a straight arm (hand instead of forearm) to increase the stability demand on the shoulder complex.

Frequently asked

What muscles does the side plank plus work?
The side plank plus primarily targets the abs, deltoids, and obliques, and also works the serratus anterior and trapezius as secondary muscles.
What equipment do you need for the side plank plus?
The side plank plus requires no equipment — just your body weight.
Is the side plank plus good for beginners?
The side plank plus is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.

Related exercises

  • 45 Degrees Arms PlankIntermediate · abs, deltoids, obliques, and pectorals
  • Alternate Knee Raise Side ReachBeginner · abs, deltoids, and obliques
  • Alternate Leg Lift Tap Arms CircleIntermediate · abs, deltoids, obliques, and pectorals
  • Alternate Single Leg Raise PlankIntermediate · abs, deltoids, hamstrings, 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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