I think at the elite level the falling record times we see are at least in part due to the new fashion of huge gears. How that translates to the local level is a different deal though. I witnessed a steady up creep of gear sizes at Hellyer amongst masters sprinters, and I'm now seeing it starting to catch on in Japan. Can't really tell if people are getting faster though, as we're also getting older at the same time! I'm trying nominally bigger gears this year, but I'm building towards September and don't really expect to see fast times until August at the earliest. Interested to hear others' experiences with this.