What type of runner most benefits from the Dragonfly/Superspikes? I've seen people say some runners are "responders", but what does that mean?
The people WHO responded to the vaporflys were runners with short ground contact time, but idk if thats the same for the spikes.
1) do they get the advertised X%+ boost in efficiency (measured in-lab or by real-world performance)? Don't think spike manufacturers have made any number claims yet, and it's hard to test track spikes in a lab, but pretty reasonable to test with performances assuming fitness is measurably as good as or worse than in prior seasons.
2) do they feel aided or hindered by the spikes; or neither? Look to Nick Willis as an example. Definitely no longer in 3:29 shape, but probably in comparable, if not slightly worse, shape than previous seasons. Feels a difference when using the New Balance FuelCell MD-X for a 1200m TT. Look to Craig Engels as another example. Doesn't feel the Nike Air Zoom Victory spikes fit his gait style, but likes the Dragonflys.