First of all I am not at all sure what is the definition "Vicious and Dangerous sports". Sports are meant to enhance your energy level, excitment, teach you team work, help you overcome stress and so on.
Now when I say this game is dangerous, it may be that the past I might have had a base experience while playing that particular game. When I play football with a few group of children its totally different experience than when I play the same game in a Club. That means that we make the sport dangerous ourself and not that the particular sport is dangerous in itself.
As for the word 'Vicious' it confuses me , if you meant addiction to sport. Even if you mean addiction to sport, I do not see it as a threat untill and unless an employee is glued to the TV set instead of being involved in his work, but, again it is not the sport that has to be blamed it is the habbit 'Addiction'. If you are not working because of addiction to Sports , someone else might not be wortking due to addiction to something else.
More over if a sports person is addicted to sports, it shows his/her involvement in the sport, which is necessary. getting addicted to your work is not wrong, getting overly addicted to something which is not your job is destructive.That should not prompt us to point out fingers at a particular sport, however, before we say futher, we need to know and categorize sports in to definition of being dangerous.
Definition of dangerous changes the way dialects change in this world.