Exercise Profile
  • Target Muscle Group
  • Exercise TypeStrength
  • Equipment RequiredDumbbell
  • MechanicsIsolation
  • Force TypePull
  • Experience LevelBeginner
  • Secondary Muscles
Target Muscle Group


Shoulders Muscle Anatomy Diagram

Alternating Lying Rear Delt Fly Overview

The one-arm lying rear delt fly is a great exercise to assist you in building a complete set of shoulders as it targets the rear delts, an often lagging muscle for many lifters.

Strengthening the rear delts can lead to improved posture and a greater level of strength on other lifts.

Performing unilateral movements can help improve weaknesses, balance your strength and aesthetic physique, and work towards reducing injuries by addressing imbalances in the body.

Alternating Lying Rear Delt Fly Instructions

  1. Grab a pair of dumbbells and position yourself with your chest flat on a bench. Your feet can be straight out behind you or used for stability on the floor.  
  2. Allow your arms to hang below the bench, and hold the dumbbells with a neutral grip.  This is the starting position.
  3. Take a deep breath and pull one dumbbell towards the ceiling using the rear deltoids.
  4. Slowly lower the dumbbell back to the starting position under control.
  5. Immediately repeat the movement on your opposite arm. This is one rep.
  6. Repeat for the desired number of repetitions.

Alternating Lying Rear Delt Fly Tips

  • Focus on the rear deltoids and not the scapular retractors. Keep movement at the shoulder blade should be limited.
  • If you experience shoulder pain during the movement then it may be beneficial to rotate the dumbbells until the thumbs are pointing away from one another and the palms are facing forward. This is also known as a supinated grip and will externally rotate the shoulder.
  • Use slow and controlled movement and don’t rely on momentum.
  • Allow the arms to move freely but avoid locking out the elbows.