Yes, Usain Bolt is a Christian. There was some discussion about this last summer after the 2012 Olympics, mainly because he appeared to be making the sign of the cross before starting on a race. Oddly enough, this turned out to be in breach of the No Non-Olympic Sponsorship rule because it could be seen as promoting religion - and the official faith of the Olympic Games was actually no faith at all, because the National Secular Society won the bid to sponsor it. So there were no religious symbols of any kind worn by athletes, and they weren't supposed to make religious references either. In fact nothing came of this issue about Bolt making the sign of the cross, but in theory it could have. (It's still not sure whether that's what he was actually doing anyway - it wasn't completely clear). Generally, though, he is quite open about being a Christian - the issue just came up because of the Olympic rules.