Smart Workout Diary

Cable One-Arm Fly Stability Ball

The cable one-arm fly on a stability ball is a unilateral chest isolation exercise performed while the upper back is supported on a stability ball. The cable provides continuous resistance as the arm moves in an arc toward the body, while the ball challenges glute and trunk stability. It can help develop chest control, side-to-side balance, and shoulder stability with manageable loads.

Demonstration

Cable One-Arm Fly Stability Ball — demonstration 1
Cable One-Arm Fly Stability Ball — demonstration 2

Instructions

  1. Set a cable pulley around chest height and attach a single handle. Choose a light load that allows smooth control.
  2. Place a stability ball beside the pulley, then lean your upper back and shoulders onto it. Plant both feet firmly, bend the knees, and lift the hips until the torso is level and stable.
  3. Hold the handle in the arm farther from the pulley with a neutral or palm-up grip. Start with that arm open to the side at chest level and a slight, fixed bend in the elbow.
  4. Brace the abdomen and squeeze the glutes to keep the ball still. Keep the shoulder blade gently set without shrugging.
  5. Exhale and sweep the arm in a wide arc across the front of the chest until the hand reaches the body’s midline. Keep the elbow angle nearly unchanged.
  6. Inhale and slowly return along the same arc until the chest is comfortably stretched. Do not let the shoulder roll forward or the ball shift.
  7. Complete the planned repetitions, secure the handle, and repeat on the other side.
Muscle Group
Chest
Type
Strength
Mechanics
Isolation
Equipment
Machine Strength, Exercise Ball
Difficulty
Intermediate

Technique tips

  1. Prioritize stability over load. If the ball rolls or the hips drop, reduce the weight and reset before continuing.
  2. Keep a soft bend in the working elbow throughout; turning the movement into a press reduces the fly’s chest focus.
  3. Use a slow return and stop before shoulder discomfort. A comfortable chest stretch is sufficient; do not force the arm excessively behind the body.
  4. Keep the ribs controlled. Avoid flaring the rib cage or arching the lower back to finish the repetition.
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