. >> soccer champion brandi chastain helped the u.s. women's team win the world cup. part. i think it's a beautiful part of the game. >> she says girls need to be taught to create protective space around theirs bodies. she says heading isn't dangerous if it's done correctly. >> okay, good. arms are out. you hit it right in the middle of the sweet spot right above your eyebrows in the middle of your forehead like that. you almost don't feel it. >> casey says she knows where that sweet spot is, but with this latest concussion she didn't see the ball coming and now she's out of soccer for the rest of the season. >> where is where is the line where you cross over and say, it's not worth it anymore? it's just a game? >> i think that our family is standing on that line right now, and it's very scary from a parent looking at your daughter with a concussion. when you see the blank stare, and if it can happen again, we want our daughter back. >> now casey's parents say they're going to convince their daughter to give up soccer for good and switch to a noncontact sport like tra