How long does the Alphafly magic last?

Many have wondered how many miles the running economy benefits last for in a pair of super shoes. For the Alphafly specifically, I compared a new pair to an old pair that had over 400 km (240 miles on them). Here's what I found.

Testing Methods

I ran in the fresh Nike Alphafly, as well as the 400 km Nike Alphafly, along with my typical control shoe (Asics Hyper Speed) for 1 rep each at 6:15/mile pace while measuring oxygen consumption and energy expenditure. Check out this link to see what running economy is, how it is measured, and how it impacts performance.

Results

I got a 4.7% running economy benefit out of the fresh pair of Alphafly. However, the 400 km pair still gave me a 4% benefit, so perhaps a slight reduction in performance but still quite good.

Take Home Message

The benefits are preserved quite will even at 400 km, which indicates that the new ZoomX foam holds up nicely in terms of performance. In terms of feel, the old Alphas definitely still feel bouncy and poppy. I tend to do workouts and small, local races in my old pair now, and save the new pair for bigger races. Soon I should be able to retest the older pair at 600 km of wear.

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