Director Steve James has earned himself a reputation for making extrarodinarily wonderful documentaries, beginning with the legendary 1994 sports doc Hoop Dreams, followed by 2002's Stevie and 2011's The Interrupters, three movies that are customarily held by fans of the form to be among the greatest non-fiction films made in the modern era. And this puts a certain unwanted stress on his latest work, Head Games, which is by no means aiming to replicate the effect of those movies; it is, to a degree that even anti-gang violence study The Interrupters was not, an Awareness Of The Issues picture, and while it follows the Steve James tradition introducing us to a person whose life seems absolutely fascinating and who, under James's lens, is made to be very real and sympathetic to us, there's not so much insight into human behavior amongst all the facts and figures and muted calls to action. This is not meant to be a slam against Head Games, which does not apparently desire to plumb such depths of psychology and insight, but rather to instruct and enlighten us about something very awful that might also be very widespread and is certainly very preventable, and considering how unengaging the subject sounds on paper, the film does a great job of being all at the same time entertaining, passionate, and intelligent in its presentation. Still, it not a film with much insight into human behavior when all is said and done, and I don't recall the last time I had a conversation in which the phrase, "that advocacy doc sure was a great work of art!" cropped up, even ironically.

The person on whom most of the movie hangs is Chris Nowinski, the author of the book which inspired Head Games and gave it a title, a football player for Harvard who was hired by WWE to play a villain (a villain whose main evil seems to be that he is arrogant about having a degree from a top-tier school, depressingly), and who enjoyed a career for almost two full years before a routine concussion left him feeling inexplicably awful, forcing an abrupt end to his career. It was this event that made Nowinski begin to investigate exactly what happens to the concussed brain, first to satisfy himself about his own situation, and increasingly, to raise awareness among other athletes who might still be able to save themselves from a similar fate. Throughout the back half of the 2000s and right up till the present, Nowinski is the public face of a movement to educate both professional and amateur athletes about the dangers of contact sports, particularly the elevated dangers to the very young, whose nervous systems are not quite fully-formed, and whose bodies are more fragile in all the wrong places.

Head Games is sort of about Nowinski, but it, too, utilises him less as a "character", than as its public face for the issue of brain trauma in sports, and while I perhaps over-state things in calling it an advocacy doc, it is surely a film with a strong perspective that it wants to communicate, about how unbelievably bad concussions can be, and how extremely easy it is to come by the things if you play American football or hockey or soccer, or other things - the film itself is largely concerned with football, because a 95-mnute film has to pick its battles pretty judiciously, and because James himself, being a good Chicago boy, has a particular fondness for that game.

Also, because the NFL, unlike the NHL (the response of both organisations to Nowinski's activism are explored in the film, with the hockey league proving much more concerned about the health ramifications), has proven shockingly intransigent to the idea that concussions are anything other than good fun, just part of the game, and it makes for more interesting cinema when you have a small group of people armed only with logic and facts going up against the most popular and romanticised sport in contemporary America. James is not, mind you, anti-football; in fact, he starts pulling his punches at the end, by talking about all the ways that, yeah, concussions and all, but team sports are good, and leaving his movie (which is clearly building up to a "Parents! Keep your children out of football!" jeremiad) with something of a flimsy, noncommittal close.

I suspect it is this intense focus on how the NFL systematically tried to downplay the seriousness of head trauma for several years (the film implies that the league is just about starting to change its behavior) that leads James to devote a lot of his movie - what I would be inclined to call an extremely disproportionate amount of his movie, in fact - to proving a thesis that I strongly doubt anyone in the audience would seriously think about denying: the notion that, all in all, repetitive blunt trauma to the head is not a good thing. This, weirdly, emerges as the main theme of the film: concussions are undesirable. Surely the country isn't in bad enough shape that this qualifies as a shocking insight? And yet, it is to proving this that James devotes the bulk of his film, painstakingly demonstrating that people who receive multiple concussions are considerably likelier than the population at large the suffer from a cluster of psychological symptoms related to the degenerative disease Chronic Traumatic Encephalopathy, or CTE, a jargony way of saying "if you get hit a lot in the head, your brain begins to rot". It's a disease linked to forgetfulness, aggression, depression, and suicide, and it is - or at least was - the case that suggesting that this disease might be caused by playing sports that involve banging your head frequently is downright radical.

To be fair to the film, there's ample evidence that, in fact, this argument does need to be made: one of the most shattering moments in the movie comes when Nowinski, addressing a school assembly, is attacked by a coach who thinks he's all full of nonsense, and when it turns out that this man's young child has herself evidenced symptoms of concussion that were not treated because that's just how the sport goes, Nowinski is visibly wrecked. Also, it's not like Head Games is a wonky slog - there are a lot of slides and photos of brains riddled with the tell-tale protein which indicates CTE, but the people discussing them are so alarmed and impassioned about their subject that it's easy to forget how, ultimately, this is ultimately just a talking heads documentary of the most basic sort. Besides which, James finds a great many subjects to inject a useful note of humanity to what could be a dully stat-and-science-driven piece: a man unable to recite the months from January to June even seconds after being reminded what they are, or a teen girl who has already suffered multiple concussions faced with the decision to stop playing soccer, her one true love.

The film is urgent and hectoring, but it's also moving and humane, and for this reason, it is a bit more palatable than most "let me teach you a lesson"-style non-fiction films. Still, there is a definite tang of the lecture hall about the movie, no matter how entertaining or human James makes it, and it's impossible to argue that it's an accomplishment on the level of his masterpieces. It's fascinating and engaging in the way of a really terrific news report, but by absolutely no yardstick is it a classic.