LRC note: We've merged two threads on the topic into 1 and combined the thread titles. The quote comes from this article: https://www.letsrun.com/news/2...
Yes, you do have a choice. Which shoe works best for you? Not all conventional running shoes are equally optimum for each runner, and the same is true for the supershoes.
It could be that some runners get more benefit than others from running on an artificial surface rather than cinders.
4% efficiency improvement equals more like a 1-3% time improvement, and that means 2-3 minutes in time over a marathon for a world elite man or woman. In the study below, men improved by 1:12, women by 3:42! So, improvements differed by time and percentage improvement between men and women as well as individuals.
Because of this (Senefeld, 2021) and a few other studies, I expected to see similar huge improvements in the elite-of-the-elite top-100 distance racers as super-shoes were adopted, but the big bumps just weren't there for the men (women, maybe). I certainly feel and see a big difference in times when wearing them.
Maybe part of the reason for the discrepancy in the studies is there's no way to hide the shoe from the wearer when testing them, and the placebo effect could play a role.
Another possibility, and what I believe, is that the shoes do help those of us whose running economy is one of the main limiting factors towards increasing our performance, but that the very best runners in the world do not gain much by it since, due to superior fitness, they essentially have their throttles are wide open all the time.
For whatever it's worth, I've tried to prove the times of elite men before super-shoes in the long-distance events are very much comparable to the times of previous years. That is to say, there has always been a general improvement in times over decades, and the improvement shown during the adoption of super-shoes was not any different for the men. For the women, it is not quite so clear.
I am planning to add the times for the events run in 2022 and 2023 to the analysis at the conclusion of this year's season and hopes it will add more clarity to the question.
Your anaysis doesn't show that the supershoes don't impact running performance. You're agument is somewhat tangential to the debate here--and that's if your data support your arguments. The following study compares marathon shoes of people who were already sub-elite or elite than either did or did not switch to Vaporfly. The analysis shows that Vaporfly shoes improve men's marathon times between 2 and 3.9 minutes. This was before other companies released supershoes.
My guess is that the runners in this study put their best footwear forward and upped their effort when wearing the new shoes. They certainly feel amazing at first.
My data for the times was simply the data on the World Athletics website. For example, below is the link for the top-100 men's marathon times in 2001. I repeated that for each year in the different long-distance events for all years through 2021, and simply calculated the average time. Tedious, but straightforward. The more complex part was trying to figure out the percentage of runners wearing super-shoes in any given year.