New Research: Are American Runners Slowing Down?
Editor’s Note: This post is written by guest contributor, Vania Nikolova, and has been edited for length and clarity. The opinions expressed in this article are the author’s own and do not necessarily reflect the views of Minneapolis Running.
In the last twenty years numbers of running races and the participants in them have risen significantly. Although there is a bit of a decline in the numbers in the last two years running races have never been more popular.
This motivated the researchers at RunRepeat.com (Jens Jakob Andersen and Ivanka Nikolova, Ph.D.) to see how the speed of the average runner is changing in time. Moreover, with regard to the increase of poor health indicators of the average American.
For this research, they have collected and analyzed almost 35 million results (of which 25 million were used) from almost 30,000 races in the four most popular racing distances – Marathon, Half Marathon, 10K, and 5K.
The conclusion is: Americans have never been slower. And this is a health concern.
- Nowadays competition is less important than participation, so more and more people just walk – the data shows that the percentage of people who finish with walking speed is near constant for the last 20 years;
- The new participants are overwhelmingly slow – after careful analysis, we see that the slowing down happens on every level
- The finish times of the 5th, 10th, 20th, 25th, 50th, 75th, 90th and 99th percentiles of the participants are increasing with nearly equal rates;
- The average times of the 100th, 1000th, 2000th and 5000th finishers also increase year after year.
- Women are the reason – the fact is that women numbers are rising less than men are slowing down.
Thus, these factors could have some impact, but they are in no way exhaustive.
The next step was that they analyzed how the trend of increasing finish time correlates with poor health indicators. And the correlations proved to be strong, coherent, plausible, 99% statistically significant and replicable. So, they could be considered inferential to some extent.
The health indicators used are:
- Adult obesity rates
- Teen obesity rates
- Diabetes and Hypertension
- Medical expenses
These indicators are correlated with the finish times in the same year and with the finish times after 3 years.
Andersen and Nikolova used both time scales to make the study coherent and also to emphasize the lasting effects of these health problems.
These correlations become even stronger with 3 years delay (the rate of obesity has a higher correlation to the finish time after 3 years than with the finish time of the same year). They have established similar correlations and dependencies for all parameters in both time scales.
Critical note: The research does not argue that the established correlations have a causal nature, or that they show the full picture. There could be an infinite number of reasons for this effect, but still, the team at RunRepeat.com think that they deserve attention.
- American runners have never been slower – across gender and distance.
- The reason for it is not the increase in the number of participants, especially slower ones – “walkers” or women.
- Poor health indicators are highly correlated with the decrease in speed.