- The average American runner have never been slower (across gender and distance);
- This effect is not due to the increase of female participants or “runners” – people who run slowly or walk the race.
- Signs of poor health are highly correlated to the decrease in speed. Though we cannot with certainty say that these are the causes for the slowdown. And if they have causal nature that they show the full picture.
—Andersen, Jens Jakob. “American Runners Have Never Been Slower (Mega Study).” RunRepeat. August 2017.