Christopher Nowinski is a former Ivy League football player and WWE wrestler. In 2006, he wrote Head Games: Football's Concussion Crisis from the NFL To Youth Leagues. The book has inspired a documentary, Head Games, that opens tomorrow in New York and Los Angeles and that will also be available on demand on iTunes. The documentary, which is directed by Steven James (Hoop Dreams), examines what the film's producers call "the silent concussion crisis in American sports." The film's official trailer can be seen above.

Nowinski is the co-founder and executive director of the Sports Legacy Institute, and he also serves as the co-director of Boston University's Center for the Study of Traumatic Encephalopathy. You may begin asking questions now.

Update (4:04 p.m.): Chat's over. Thanks to Chris for joining us. The entire Q&A can still be read below.