not talking about elites as I've never really watched them, but whenever I am out running it's pretty easy to identify a tri-focused person as their shoulders are super stiff, their body is completely vertical, and they don't seem to use their hamstrings or butt at all in their stride ... it looks like all the mechanics are in front of them as if they are just putting their feet in front of them but not propelling themselves at all.
Are they all taught to run this way? or is it a consequence of fatigued muscles from swimming and biking?