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  7. Lying Prone A

Exercise guide

Lying Prone A

  • Beginner
  • Compound
  • Rep-based
  • Back

The Lying Prone A is a highly effective isolation exercise for strengthening the posterior deltoids and lower trapezius, essential for improving posture and shoulder stability.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Lying Prone A demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Deltoids

Secondary

  • Abs
  • Erector spinae
  • Obliques

Equipment

  • Body weight

Setup

  1. Lie face down on a flat surface with your legs extended and the tops of your feet resting on the floor.
  2. Position your arms by your sides with your palms facing your thighs or the ceiling.
  3. Tuck your chin slightly to maintain a neutral spine, keeping your forehead hovering just off or resting on the floor.

How to do it

  1. Exhale as you lift your arms toward the ceiling, keeping them straight and close to your body to form an 'A' shape.
  2. Squeeze your shoulder blades together and down toward your hips at the top of the movement.
  3. Inhale as you slowly lower your arms back to the starting position using a controlled 2-second tempo.

Form checklist

  • Keep your forehead down to avoid straining the neck.
  • Focus on moving from the shoulders rather than just lifting the hands.
  • Keep your glutes and core engaged to prevent your lower back from arching.
  • Ensure your arms stay straight throughout the entire range of motion.

Pro tips

  • Think about pulling your shoulder blades into your back pockets to maximize lower trap activation.
  • Rotate your thumbs outward at the top of the movement to further engage the rotator cuff and rear deltoids.

Make it harder

  • Hold the peak contraction for 3-5 seconds on every rep to increase time under tension.
  • Perform the movement while holding light weights or household objects to add resistance.

Frequently asked

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

Related exercises

  • Alternate Front Kick In Place With Arm CirclesBeginner · abs, calves, deltoids, and pectorals
  • Arm-Up Rotator StretchBeginner · deltoids
  • Arms Forward And Behind The NeckBeginner · deltoids and pectorals
  • Arms Stretch On A SupportBeginner · biceps, deltoids, and pectorals

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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