Maybe for a few but not for the majority. I have several friends who I competed against in the late 80s and early 90s on the NASKA national circuit who are now in Hollywood and been in various movies. Ho Sung Pak, Billy Blanks, Mike Chat, to name a few and when they signed contracts their competition days were basically over. Most agents and studios want their people at the ready basically rather than laid up by injuries and such.
If you notice Jackson only has made one movie, and Couture of course is retired and Rousey has only had a part in one movie also to this date because of this. So being a fighter does not translate into being in movies for most fighters usually.
Not the overwhelming majority of the time. You've named three fighters in an organization with over 100 of them on its roster.
If you're a really good fighter with a strong personality and good media presence, being in a movie or two is possible. But champs and former champs (Jose Aldo, Frankie Edgar, etc) don't get movie roles. Most of the time, they aren't starring roles, either- you can count the number of lines Couture has in the Expendibles franchise on one hand.
It could. Not as likely as actually going into acting, but it could still open up possibilities.
dont forget GSP. he's in captain america, haha
ronda rousey randy couture and rampage jackson
