I didn’t realise that runners over different distances had strong preferences for different track materials (longer distance runners prefer springier material).
Given that these elite athletes are supported in every other possible way (don’t start me on the 30 miles of ‘VIP’ lanes through London), why not give them tracks they want to run on?
Today’s invention is therefore a running track laying machine which can lift the entire width of the track (like a wide carpet) and replace it with alternative material.
This could even be automated so that 400m could be replaced in a few minutes. The 10,000m could thus follow the 100m immediately if required to do so (by the TV schedulers).