Sylvester Stallone says he doesn't advise actors to do their own stunts in the movie biz ... and 7 surgeries oughta serve as a warning -- you listening, Tom Cruise???
The legendary action star made the revelation in a recent episode of his Paramount reality show, "The Family Stallone," where he said he'd undergone more than half a dozen back surgeries to deal with an injury he suffered on the set of "The Expendables" back in 2010.
Basically, Stone Cold Steve Austin -- who's also in the movie -- was body-slamming Sly on set .