If your friend jumped off the Brooklyn Bridge, would you jump, too? What a dumb question our parents used to ask us. Of course we wouldn't. We don't live in New York. BUT, if your friend (or, say, 20 of them - and a big, strong trainer dude) did a gazillion lunges in a public park on a hot afternoon, would you lunge, too? The answer is yes, at least if you invested in a four-week boot camp in Piedmont Park led by the Body Firm Atlanta. Lead trainer Dez White, a former wide receiver for the Georgia Tech Yellow Jackets, the Chicago Bears, and our own Atlanta Falcons, says his plan is to push people to reach their personal fitness goals by figuring out where they're starting - whether they're fitness beginners or advanced exercisers. His rates are reasonable, too: $75 for four weeks of training. (There are other locations, mostly OTP, and programs that vary in price.) "Peer pressure" has a negative connotation, but when you feel like giving up, it sure is helpful to have people beside you urging you on. Not as painful as jumping off the Brooklyn Bridge, but you'll feel the burn. www.thebodyfirmatl.com.