That fickle feeling of speed

I would be willing to bet that this has happened to most people who drive: You travel some long distance on an interstate highway and then the last few miles to your destination are on regular streets. You look at the speedo and are doing 65 in a 30 MPH zone! It is perfectly understandable, not to a police officer of course; you've gotten used to tooling along at 80 and so 65 seems slow. You really have to rely on your instruments.

Speed, when running is measured differently than in driving: Runners will mostly express their efforts in minutes and seconds per mile. The range of speeds is much narrower than when driving. Drivers could realistically expect to be going anywhere from 25 MPH to 80 MPH while a typical runner may go as fast as 6 minutes per mile (in a short race) to as slow as 9 minutes per mile in a long slow workout. This is a range of only about 4 miles per hour. Even with this small range, it is easy to tell within 20-30 seconds/mile what your pace is.

In spite of this fine precision, one still feels the effects of habituation: For instance, I have been injured for a few months and now that I am feeling better, am trying to get back to my usual speed. At my age, I need to run 8:00 minutes/mile to qualify as an entrant into the Boston Marathon, so I naturally try and keep all of my training runs at or below 8:00 per mile. Last week I finally broke 8:00 a couple of times and not by more than a second or two per mile. It felt really fast and not due to effort--my cardiovascular system is not being pushed at this pace. I'm just not used to this speed. Again, it is good to have instruments: In this case a digital watch with a timer on it. If it wasn't for the watch I would think I was right back up to speed, rather than around 30 seconds per mile slower than I ought to be for these distances.