sesame,
if u hv IBS, u will prob hv it before u start cycling. symptoms are frequent unexplained abdominal pain/discomfort, bloating and gas. bowel movements tend to swing from end to end, either constipated or loose stools. definitely not the everyday regular bowel movement type.
there is no diagnostic test for IBS, is just a combination of symptoms together with no other medical reason then dr usually conclude it's IBS.