Well, Kartoffeln and I were testing out Athletics and Armor weights...It seems like in the recent patch, the effect of armor weight on run speed is drastically altered. It seems like acceleration is given a little boost if you're wearing lighter armor but that is about it. Heavy armor also loses a little max speed. However, the difference was not noticeable when we both had 7 athletics. Kart was wearing Milanese Plate with Helmet and Boots, while I wore Black Lamellar + Leather Gloves/No Helm/Light Strange Greaves.
However, we did not do any of the in-depth timing. :[