After this year's Paris marathon, I ran the same per-minute graphs, and they match perfectly the "overall study" graphs with more than 9 million finishes in the article. I also added graphing by age category and gender. I don't want to deduce too much but I think it showed that young men are the most "competitive" (what I mean by that is targeting a specific time) since there are the clearest "goal time" peaks in the graphs.
IIRC There is also a discontinuity when it comes to the histogram of ages of marathon runners, because runners are binned into age groups and there is a more runners at the youngest ages of each group, I guess because itβs younger runners in each group that are more likely to run if they feel more likely to place well in their group
I think there's also the opposite β there are a number of places in large marathons allocated for "good for age" entrants, which I would guess are more likely to be taken up by people at the younger end of those buckets.
