Playing sports comes with risks. Contact sports like lacrosse, boxing and football, for example, are the most common causes of avulsion fractures. It’s because contact sports involve movements that stress your limbs, such as: Suddenly changing direction. Sprinting. Kicking. Leaping. Falling on an outstretched hand. Suddenly accelerating (getting faster) or suddenly decelerating (going slower). Hitting, as in a boxer or a defensive lineman in a football game hitting an offensive lineman to protect the quarterback. Sliding, as in a baseball or softball player sliding into home base.