I love the Vaporfly as a shoe, and I’ve run five marathons in different versions of them. I think the general view is that to see any benefit, you should be sub-8 min/mile. You apply less force on the plate and foam at lower speed, so you get less energy back. Also, the high stack height makes them more unstable, which is a bigger issue at slower paces. The Nike ZoomX foam is also more fragile, so I just use the Vaporfly or Alphafly for races, while I daily run in my Adios Pro 3 or Endorphin Pros.
- 6:02 minutes per mile pace: A 2022 study found that the Vaporfly improved running economy by about 2.7% compared to a control shoe.
- 8 minutes per mile pace: the Vaporfly improved running economy by 1.4%.
- 9 minutes and 40 seconds per mile pace: the Vaporfly improved running economy by 0.9%.