User: What do players of American football wear helmets? Write the response as if your are an American explaining to a coworker from another country.
Assistant: American football is a high impact sport where injuries such as concussions are very common. The helmet is meant to lesson the occurrence of traumatic brain injuries like concussions by providing padding to the skull. The helmet is hard shell on the outside with soft padding on the inside. Players are required to wear them anytime they are on the field of play. Helmets were originally made of leather but over the years improvements have been made to better protect players.