It varies, if you are playing tackle football it is more likelier than if you are playing tennis... Although, you never know when it is going to happen, it could happen without you even knowing!
The most common ways to break your Arm Naturally: A broken arm may involve any of the three bones in your arm - the ulna, radius and humerus. One of the most common causes of a broken arm is falling...
You need to apply enough pressure to the bones in the arm to compromise the structure of the bone, causing the break. This will result in an extremely painful result.
No need you can buy tape online, see related link. but if you really want to jump off a highchair or something and put you fists out them bend you wrists towards your Chest an jump fist first.