1. If the weight of the dumbbell is too large, when the dumbbell is used to practice side-lift and front-lift movements, because the arm needs to be straightened and slightly bent, it will cause gravity damage to the elbow joint, and it will naturally hurt if it is practiced too much.

If this is the reason, you need to reduce the weight of dumbbells immediately. Every joint of the human body is very fragile and difficult to repair. Therefore, exercise should try to avoid joint injuries.