This is an embarring question for me?

I'm being serious btw. I do Taekwondo and Judo. I've had a little break from it, but gone back recently. During the exercises at the start (running etc) I keep farting. I get really embarred by it (I'm quite shy and hardly talk). One bad thing is the cl has lots of hot guys in it and I'm not sure if they can hear it or not (they could probably smell it at least). How do I stop farting? I do this towards the end of races too. Also has this ever happened to you? Thanks... Sorry if it's gross.