I too, work out really hard at the gym and I've not had any treatments effect while working out. I take a class, and occasionally we have partners for certain exercises. Well, I have had problems with gas. So far, in a month, I have yet to let one slip out, a fart, that is, but I've held it in until I felt like a would literally blow up, cause them alli farts can be nasty! And I would literally die if I let one out in my partner's face!
But if you stick to the fat grams you're supposed to, you should be fine. I don't think it's the jumping around and straining that does it, but just the fat grams.