They're analyzing the first runner's form on a downhill. You need a level surface to analyze form correctly.
This is an incredibly idiotic article. Circular reasoning out the wazoo. And willpower is the reason we slow down at the end of races, so if we just try just a little harder, we won't slow down?
"He's got a slight knee lift to insure his foot lands in front of him, not behind him."
This guy is a paid researcher?