The guest for this episode was Dr. Kim Hebert-Losier, a French Canadian sports scientist, specifically an applied biomechanics, senior lecturer in Waikato University in New Zealand. As said in the title, the main topic that they discussed was her research article, and its' information about Nike Vaporfly, and whether or not it was actually considered as a biomechanical doping shoes.
Dr. Kim's research paper titled 'Evidence of Variable Performance Responses to the Nike 4% shoes' was already complete, and would be considered as a pre print, which means that it was publicly published, and only lacked the peer-review.
She was asked on her opinion whether or not she thought that the shoes improved performance and she said "If you look at the evidence, it's kind of hard not to say that they [Nike Vaporfly shoes] improve performance."
Dr. Will also asked her "What did you want to achieve by doing this paper?" Dr. Kim explained that all of the current research at that time (before she did the paper) was all in elite, or highly trained runners, which means that the subjects of their tests were from a selected, relatively small sample compared to the actual number of consumers that were not necessarily elite runners. She also described that there a whole lot more recreational type of people than the elites from all of Nike's customers.
According to what Dr. Kim said, "I guess the main drive was to actually see if your more average day-to-day runners could improve with the Nike Vaporfly."
The baseline assumption of the article would be that people who were used to wearing shoes that were "more comparable" to the Nike Vaporfly might respond better to Nike Vaporfly, or if runners were more used to wearing lightweight shoe, then they might respond better to wearing a lightweight shoe.
The three (3) shoe conditions they used were; individual's own running shoes, the Nike Vaporfly, and Saucony Endorphin Racer (a racing flat, lightweight shoe).
They also tried to minimize personal bias from the subjects by spray-painting the Nike Vaporfly black so it would be more difficult to recognize.
According to the podcast, they tested, and considered many aspects for the comparison of the three shoes, their variation (based on either the surface inside the shoe, the "grip" of the bottom of the shoe, loading, etc.), or the subject's feedback to each variables.
In the end, Nike's Vaporfly was considered to be more economical "energy saving" in a sense, but the Vaporfly was not guaranteed to improve performance when they were used by recreational runners. The main consensus of the researchers was that the Nike Vaporfly could potentially alter the running mechanics much more in this group of lesser-trainer runners. On the other hand, the racing flats improved performance across the board due to their light weight.
If you wanted to check out Dr. Kim Hebert-Losier's whole article, here is the link: https://osf.io/preprints/sportrxiv/ctavy/
Hébert-Losier, K., Finlayson, S. J., Driller, M., Dubois, B., Esculier, J., & Beaven, C. M. (2020, January 29). Evidence of variable performance responses to the Nike 4% shoe: Definitely not a game-changer for all recreational runners.