However, the 4% shoes need a new name. 2.7%.
Podium runner wrote:
This raised a serious problem for Ward and other non-Nike athletes. How could they make sure, at the 2020 Marathon Trials, that they wouldn’t get beaten by a rival’s shoes rather than the rival’s talent and hard training?
To answer that question, Ward joined a BYU research team that analyzed the Vaporfly 4% shoes. The results of that study have just been published by the Journal of Sports Scientists. The BYU group found the Vaporfly shoes improved runner efficiency by 2.7 percent—not quite as much as other reports, but similar.
“I’ve never stood on a starting line and thought my opponents were using better equipment than me,” notes Ward, a BYU statistics professor who helped with data analysis of the BYU study. “But when you see actual, measurable results with your own eyes, it sparks a quest to find out how the shoes work.”
The BYU paper produced several possible answers. In particular, when test subjects wore the Vaporfly 4% shoes vs Adidas Adios Boost shoes and Nike Zoom Streaks, they ran with greater vertical oscillation—or “bounce”—and a longer stride. Vertical oscillation is often considered wasted movement, but that’s not necessarily the case if it increases stride length without requiring additional muscular effort. And that’s what the BYU researchers observed. The bounce came from the shoes, not the leg and foot muscles.
That's from an article on Podium Runner that is pretty interesting. It talks about how Ward is working on helping Saucony close the gap. Apparently, they've already got a prototype out that is already really good.
That's the good news.
The bad news is it appears that Ward's 2:09 from Boston should be struck from the record books. Now we all know that won't happen but I'm not sure why no one at the IAAF is enforcing their new rule about pros only being allowed to run in shoes that are commercially available. Laura Muir's UK indoor mile record hasn't been stricken from the books either.
"Rule 143: Clothing, shoes and athlete bibs
- Any type of shoe used must be reasonably available to all in the spirit of the universality of athletics. Shoes must not be constructed so as to give athletes any unfair assistance or advantage."
Here is the article:
and the scientific paper: