Full tears:
sudden loss of strength - confirmed with resisted testing
sudden loss of strength is rare in younger populations as the tendons are healthy and robust, so is more common in the older populations, where they'll have changes to the quality of the tendon, but may not be experiencing any pain
sudden inability to actively raise arm - might have to use trunk to lean/swing arm
pain free, full passive range of movement
onset can be a regular everyday activity - more common in older population
more of a chance pts will need orthopaedic consultation