As a nation that invented both football and rugby, it's no surprise that the US game of American Football has been looked at with such disdain on these shores, with its sissy approach to being a sport. It stops and starts a lot, and although it's admittedly a physical game, with all the padding and helmets, it doesn't really compare to the Neanderthal bone-crunching physicality of our rugby.

Still, even with all the protection the game offers, players can suffer from some incredible injuries. One that was often swept under the carpet was the effect the game had on the brain. And when one doctor decided to look into the repercussions of the constant impact to said organ in games, he didn't realise he would have to tackle the mighty NFL head on.

Nigerian-born Bennet Omalu (Will Smith) moved to the US to continue his on-going medical career, which led him to Pittsburgh Pennsylvania, where he practiced as a forensic pathologist. If there's one thing Pittsburghers love it's their sport, particularly their football team the Steelers.

When former Steelers legend Mike Webster (David Morse) turns up on his slab for an autopsy, Bennet discovers that the ex-player's early demise was attributed to severe brain damage. After further investigation, he found that this wasn't uncommon amongst players.

This led him to co-write a paper in a medical journal highlighting his findings, and giving it a name - chronic traumatic encephalopathy (CTE). When the results made the front cover of a prestigious newspaper, it caused warning bells to go off at NFL HQ.

Bennet believed he was doing good in bringing this to the attention to the public; what he wasn't expecting however was to go head to head with one of the biggest and most powerful organisations in the US.

Although having such a bankable star such as Smith on board, Concussion was always going to be a hard sell. Sports films are a niche market as it is, but despite having US football as a backdrop, this film is not a sports flick. The problem is, it's a medical drama with a sporting motif, which is probably even more niche.

Ironically, for a film about head trauma caused by players getting hit hard in the head, this one lacks any real impact. Besides Smith rattling a jar with a fruit in some water to represent the movement of the brain, the film relies on TV footage, over and over, of players being knocked around during a game. You're more likely to flinch watching a sports fail on YouTube than watching these.

You can tell that this is only the second feature by director Peter Landesman. He struggles to know exactly how to communicate the theme of his film onto the screen; when he introduces a number of players who are struggling with the mental disorders they've received from playing, it feels as if they're all suffering from some kind of zombie virus.

Landesman is lucky enough to have a strong cast however, who know what they're doing. Most notably is Albert Brooks, who proves in the very little screen time that he has, that it's almost criminal the lack of films he's appeared in of late.

And although audiences may well come away with a 'meh' attitude towards the film as a whole, there's no denying that Smith, with yet another warm and winning performance, is proving to be a formidable talent, with no doubt his best work still ahead of him.

As far as the film is concerned, it's trying to convey a sense of shock at a doctor coming to the conclusion that - surprise surprise - playing American football can cause long-term head injuries. And if an audience don't know that going into the film, well, they probably need their head examined.