Sit upright in a chair with your hands relaxed by your sides.
Have an assistant help to support your arm at your elbow and hand.
Slowly lift your weaker arm out to your side, keeping your elbow straight.
The assistant should help by supporting some of the weight of your arm.
Hold your arm above your head before slowly lowering it back to your side with support from the assistant.
Ensure your back and neck muscles remain relaxed as you move your arm.
Do not hunch your shoulder during the movement.