I just saw this in a running magazine: it's a race for "fat people" (men weighing more than 90kg, women more than 80kg). With a small effort I can get back to 90kg easily but perhaps it wouldn't be too sporting because, at my height, I wouldn't be classified by many as overweight. It would be fairer to use the BMI (Body Mass Index - based on your weight and height).
Seriously, though, I have often thought that it would be great if a "heavyweight" category were introduced. For years in rowing I was just the wrong side of lightweight - being small in rowing is a distinct disadvantage. Having said that, had I managed to make the weight I would probably have been that much weaker and prone to injury so who's to say I would have had any more success than I did. Still, I do find it odd that many sports do have a weight categorization while running does not; you only have to look at the size of the people lining up at the front of any race more than 400m to see that size matters.
By the way, I have no illusions that I would be especially competitive in a segregated "heavyweight" category but I'm sure it would open up the sport to others who perhaps scrape by in less popular sports like rowing or canoeing. I expect that Great Britain would also pick up some more medals as it seems that, due to our size, we excel in those sports that involve sitting down.