12mph is BIG INCREASE in speed. I wouldn't say that is the average. Unless you are simply outta shape and your speed just goes down that much. For instance you had back pain which probably seriously hindered your speed.
Huge! The back pain was definitely a hindrance. I was up around 115mph beforehand, and with help from this site and Brian's and Brian, could account for some of the rest. I am getting older though!
I do stand by my endorsement, although I better shut shut up soon, lest y'all think I'm a spokesperson or something