External Rotation — start position
Start
External Rotation — end position
End

Shoulders / Beginner / Isolation (single joint)

External Rotation

A dumbbell isolation exercise for the rotator cuff.

At a glance

Primary
Rotator cuff
Equipment
Dumbbells
Movement pattern
Shoulder rotation
Level
Beginner
Type
Shoulders, Isolation (single joint)

How to do it

  1. Lie sideways on a flat bench with one arm holding a dumbbell and the other hand on top of the bench folded so that you can rest your head on it.
  2. Bend the elbows of the arm holding the dumbbell so that it creates a 90-degree angle between the upper arm and the forearm. Tip: Keep the arm parallel to your torso.
  3. Now bend the elbow while keeping the upper arm stationary. In this manner, the forearm will be parallel to the floor and perpendicular to your torso (Tip: So the forearm will be directly in front of you). The upper arm will be stationary by your torso and should be parallel to the floor (aligned with your torso at all times). This will be your starting position.
  4. As you breathe out, externally rotate your forearm so that the dumbbell is lifted up in a semicircle motion as you maintain the 90 degree angle bend between the upper arms and the forearm. You will continue this external rotation until the forearm is perpendicular to the floor and the torso pointing towards the ceiling. At this point you will hold the contraction for a second.
  5. As you breathe in, slowly go back to the starting position.
  6. Repeat for the recommended amount of repetitions and then switch to the other arm.

Common mistakes

  • ✗ Elbow drifts away from the body.

    Why it hurts: The movement turns into a shoulder swing and the small cuff muscles do not work.

    ✓ Instead: Tuck a rolled towel between the elbow and ribs and keep it there.

  • ✗ Using a heavy band.

    Why it hurts: The rotator cuff is small; heavy loads make bigger muscles take over and can irritate the tendons.

    ✓ Instead: Choose a light band for 15–20 slow, controlled reps.

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Muscles worked

Neck (Front)Upper traps (Front)Front delts (Front)Side delts (Front)Chest (Front)Serratus anterior (Front)Biceps (Front)Forearms & grip (Front)Abs (Front)Obliques (Front)Hip flexors (Front)Quads (Front)Adductors (Front)Shins (tibialis) (Front)Calves (Front)Outer shins (peroneals) (Front)Feet (arch & toes) (Front)Neck (Back)Upper traps (Back)Upper back (rhomboids, mid/lower traps) (Back)Rear delts (Back)Side delts (Back)Rotator cuff — primary (Back)Lats (Back)Lower back (erectors) (Back)Triceps (Back)Forearms & grip (Back)Hip abductors (glute med) (Back)Glutes (Back)Hamstrings (Back)Adductors (Back)Calves (Back)
FrontBack
  • Primary: Rotator cuff

Best for

How specific this exercise is to each movement.

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Photos and instructions: free-exercise-db (github.com/yuhonas/free-exercise-db), public domain.