While success in many sports often depends upon skill and delicate finesse, there is also a place for force and sheer brute strength.
Throughout the years, sport has seen a number of truly terrifying competitors who will undoubtedly have given their opponents many sleepless nights.
Whether it's their presence, persona or sheer dominance in their particular fields, such stars have formed truly formidable reputations that are sure to linger long after retirement.
One of sport's most frightening characters was boxing legend Mike Tyson. Last week, the former heavyweight champion gained widespread press attention with the eagerly-anticipated release of his controversial memoir - 'The Undisputed Truth'.
Here, in honour of the book's release, GMS selects 10 of the scariest stars ever to compete in the world of professional sport.
We have tried our very best to include a healthy mix of present and past athletes from a range of different sports, so some more obvious names may just have missed out.
Feel free to comment on our selections below. Which one of these stars is the most terrifying?
Who do you feel should have made the list?
Click on to see our choices...