In June 2004 (
https://forums.runnersworld.co.uk/discussion/40084) I participated in a blog discussing the link between postural distortions and foot mechanics. Since that time, research has revealed a great deal more information regarding foot mechanics and its' impact on performance levels in all sports.
Linear mechanics is the one of the most important determinants - separating the good athlete from the great athlete.
Specifically, in runners, take a look at the following page -
http://www.iarpt.com/cross-country---runners.html It discusses two very gifted runners, Sarah Baster and Chelsey Totten. You will find the photos compelling. What separates these two runners is mechanics: Sarah Baxter - Linear Mechanics - 1st place, Chelsey Totten - Torsional Mechanics - 2nd place.
Professor Rothbart