I received an email from Ted Witulski (NCEP coordinator for USA Wrestling), letting me know that ESPN declared boxing, ice hockey, football, and basketball as tougher sports as its fifth ranked sport: wrestling.
There is an ESPN follow-up poll at
http://sports.espn.go.com/espn/page2/sportSkills , if you'd like to express your opinion.
Follow this link, and in a box on the right hand side (titled "SPORTSNATION: DO YOU AGREE?") you can go to a link to vote your toughest sport. Currently, the votes put wrestling at #3.