Is it not a sin to participate in or to encourage dangerous sports? I'm talking about, for example, cycling on mountaintops in these popular Red Bull events, motocross, jumping in skis and snowboarding, skydiving, bungee jumping, rock climbing with no ropes, etc. The 5th commandment requires us to protect our health and safety because our body is the temple of the Holy Ghost and given to us by God for our care.
You have to ask yourself, for what purpose are these people doing it for? A thrill? An adrenaline rush? To achieve something novel? To be cool, to beat the other guy (competition), to get money, fame. Pride? To show that one is physically tough/manly and "fearless"?
Even more so, if we have a wife or children, we have a duty to them. Busted up in a hospital bed is not going to help your family, but you become a burden. "But, honey, I was this close to winning the Red Bull Rampage. A rock slipped out from under my tire. Now I’m a cripple.” Not to mention inordinate amounts of time spent on sports which leaves no time for our duties to God. Or if you die crashing your dirtbike, what will you say to God at your particular judgement?
More worthy of respect would be a man who does his duties faithfully, works hard, and pleases God first. People seem to find the saint boring, but glorify the modern sport hero.