- #36
A.T.
Science Advisor
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200N seems consistent with this:luigidorf said:Also, the running graphs that you found (thank you by the way) are from a runner with poor form: the spike that occurs around 0.1 s on the vertical force graph is representative of a heel-strike, which results in a significant breaking force and thus requires more propulsive force. For a runner with good form, there would probably still have to be a slight horizontal force to prevent torque, but I think it would be significantly less than 200 N.
http://jeb.biologists.org/content/203/2/229.full.pdf
Where they tested 8 "experienced treadmill runners" (control without modifications).
Peak breaking force : 221±5N
Peak propelling force :169±4N
And this:
http://www.mlmixrunning.com.br/artigos/subida_descida.pdf [Broken]
Level TM control:
Peak breaking force : 195±21N
Peak propelling force :169±12N
But maybe you mean forefoot strikes? They have no heel strike peak:
https://www.youtube.com/watch?v=TjrEyfQC5NQ
Compared to heel striker:
https://www.youtube.com/watch?v=wuBLkKnNKm4
I assume the horizontal peak is smaller as well for forefoot strikers. But the horizontal impulse might be the same, just distributed over a longer time span.
But regardless what the horizontal forces are, there is no mechanical reason for a difference between a treadmill at constant speed and running on ground with zero relative wind and constant net running speed. And the measurements with the instrumented TM show the same forces as on ground.
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