im sure there is a positive relationship between marathon time, and weight of the competitor. have there been any studies done to compare the two variables? what would say an extra 10 lbs added to an athlete do to their marathon time. say someone who is 130lbs running vs 140 lbs?
About 1 minute per pound. So that runner would be about 10 minutes slower.
If both are equally trained, the lighter person will be faster. I've never run a marathon, but I look like the people who win them. My BMI is 19. However, you'd be surprised how many stocky people whizz by me in my local 10k road races. This is because they are likely running 40-50+ miles a week, whereas I'm running 25.