your optimal shoe design depends on how you foot strike and stride, and your speed,
and the study needs to be on elites only at elite pace to be valid.
and athletes tested need to wear the right shoe for them to determine the advantage.
at the crux, the shoes back in the day, some were injury creating, if not most, and i'd like to see an injury study on super shoes, to see if in fact they create a more natural movement.
and proper study can provide an approximate equivalent advantage so historic times have their proper acclaim.
in fact, all times that were not drug tested, are not valid technically today, so there needs to be a non-tested era, a synthetic track era, a super shoes era, to make any sense what so ever about times over the years.
i'd like to see someone put together a cinder track with the same specs and condition of Jim Ryuns WR, run solo, with 52-53 400 finish, and pay $1M to anyone who can do it solo, in Ryun's same shoes.
Now that would put things into perspective.
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studies involving 5-6 minute mile pace don't apply to 430 mile or 343 mile situations.
one study i saw, they were analyzing the stride, foot strike of "runners" and they choose something like the 30km mark in a marathon. it's like a boxer in the later rounds getting punched in the face, and you come up with the idea that the guy can't walk properly.