Bio-mechanists have incredible tools & wonderful training that tells us what our limbs are doing when we run. They also have pretty amazing tools to measure how much our muscles are working & when. The concept of “rebound” or elastic return is harder to measure – only a few labs can do this & the results are hard to nail down – an essential, but pretty new field of research. Add to this that the picture of running effectively mechanically has no real set of baseline data that represent perfect form – there are so many idiosyncrasies in top runners. Some, like Haile Gebrselassie have tried to effect changes to no avail, but have made changes to other things, like foot strike, in his case & have gone on to succeed admirably after these changes. Generally change introduces other variables & often a whole new set of problems. This is why wise coaches sometimes leave well alone. “Don’t fix it if it ain’t broke” holds especially true when it comes to running mechanics. Most individuals I see come for 2 reasons:
1. They are broke or
2. They’re stuck & cannot go faster
Both good reasons if all the other factors have been considered; things like over-training, incorrect training & insufficient training. Nowadays, with the elites, I am finding that they cannot run fast enough with their current form to access the type of training response that will take them to the next level.
IF YOUR CURRENT TOP END REPRESENTS ONLY A SMALL INCREASE IN SPEED FROM YOUR REQUIRED RACING SPEED, BE THAT FOR A 5KM OR A MARATHON, THEN THE LIKELIHOOD OF YOU MAINTAINING REQUIRED SPEED FOR THE DURATION BECOMES MORE & MORE CHALLENGING.
A car that has been designed to drive along at 100mph is likely to be much less stressed at 65mph than a car that can only manage 70mph.
If one accepts that we have a fixed rate of slowing with each doubling of distance, & I do believe this, then ultimately you have a finite speed at which you can run your preferred distance run, no matter how much fitter you get.