The other thing that gets talked about so much is movement efficiency with screening galore, and lots of evaluation at slow speeds and corrective exercise at sometimes even slower speeds.
Elastic responses in running contribute a huge amount to speed reserve. Some athletes are more elastic than others, but injuries can create a massive impairment with that bounce we need to be efficient runners. Strangely many coaches talk about efficiency, what are they measuring? I have been using some therapists that use vibromyography in efforts to gage not just tonus, but the efficiency beyond a just jump mat score. Speed and endurance is not incompatible at moderate levels of conditioning because you are only as in shape of the sub-maximal velocity you can sustain. I have seen huge improvements with on athlete I am working with and because he is learning to simply learn to relax while exploiting the natural stretch reflex. Aaron’s post can be found here.