The Slow Study

Of the limited super shoe research, most is focused on speeds of 14 km/h and faster in the Nike Vaporfly line. These data have mostly shown improvements in running economy in the 2.7-4.2% range on average. We tested 16 runners at 10 and 12 km/h. Here’s what we found.

Testing Methods

Running economy was measured in the Nike Vaporfly Next% 2 and a mass-matched control shoe (Asics Hyperspeed) at 10 and 12 km/hr in 16 runners (8 males/8 females). Runners completed 4 x 5-minute trials at each speed on the same day. Each shoe was tested twice at each speed in a counterbalanced, mirrored sequence. Check out this link to see what running economy is, how it is measured, and how it impacts performance.

Results

The percent improvement in running economy from the Nike Vaporfly Next % 2 was 0.9% at 10 km/hr and 1.4% at 12 km/hr. This is smaller in magnitude than the 2.7-4.2% benefits previously shown at faster running speeds (14 km/hr and faster).

Compared to the group averaged responses at 10 and 12 km/hr shown above, here is a look at how my personal testing broke down across 10-16 km/hr. While the Nike Vaporfly Next % 2 provided a substantial benefit at all speeds, the benefit was much greater at 16 km/hr (3.8%) than at 10 and 12 km/hr (~1.5%).

Take Home Message

The Nike Vaporfly Next % 2 still provides substantial benefits to running economy at slower speeds. However, these benefits may be smaller in magnitude than previously shown at faster speeds. There is also more variability in the responses at slower speeds with more non-responders or even negative responders to the Vaporfly.

Links to Research Paper

Preprint (Open Access)