Is this the glitch you're referring to?

Emulators are allowed, but they're hidden on the leaderboard by default, so you'll have to click Filter > Emulators > Shown in order to see them. Also, video evidence isn't needed unless you get a time that is fast enough. For example, for Super Mario Sunshine Any% speedruns, a portion of the category rules states, "Video proof is required for runs under 1 hour 25 minutes," but as far as I know, the minimum time you can get on a run for this game before needing video evidence hasn't been decided yet.

You need to be holding Y to run up a steep slope and then perform a slide kick. (Hold forward, and then press R and A) Immediately after slide kicking, press B to roll out and keep holding forward and Y. Then you just repeat the previous steps. (Run up a slope, slide kick, and press B to roll out) I hope this helped! :)