The overload pattern of the throwing shoulder: thousands of throws build up the internal rotators and leave the external rotators as the weakest link.
Shoulder problems in handball are not bad luck, they are the norm: across a season, depending on the survey, 17 to 41 percent of players report them. The mechanism is simple — every throw trains internal rotation, and almost nothing in the game trains the opposite direction. So the best-documented risk factor is exactly that: weakness of the external rotators, with an additionally raised risk in women. The classic mistake is waiting until something actually pulls. A resistance band and ten to fifteen minutes per session, two or three times a week, is the whole investment. The underrated second lever is fatigue: it lowers throwing speed and quietly drops the elbow — less accuracy and more stress on the joint. So put throw-heavy blocks at the start of a session, not the end.