Rules of Thumb

It's an interesting phrase - "A Rule of Thumb" - and according to Wikipedia its origin is uncertain.
 
"The term is thought to originate with carpenters who used the width of their thumbs (i.e., inches) rather than rulers for measuring things, cementing its modern use as an imprecise yet reliable and convenient standard."  

I happen to be a believer in Rules of Thumb.  As someone who has done quite a bit of carpentry, the Rule of Thumb to "measure twice, cut once" has proven to be uncannily good advice, as I have learned to my regret on more than one occasion.  And every stone mason, which again I consider myself to be, knows the old principle, "one stone on two, two stones on one," which is why all of my stone walls here at our home - some of them constructed nearly 30 years ago - have still not cracked.

Runners have Rules of Thumb, too.  There is the old formula for how much a pound of flesh costs (and I'm not talking about The Merchant of Venice here):  two seconds per mile per pound.  That is the amount of time over distance one can expect to gain by losing weight, down to one's optimum weight (below which diminishing returns can be expected).  Translated into time, a runner who is ten pounds over his ideal weight can expect to lose 20 seconds per mile, or 8.73 minutes over the course of a marathon - a considerable cost in time.

Today I used a Rule of Thumb which has also proven reliable over time for me:  do no hard running for as many days after a race as the number of miles in the race.  So, for a 10-K, I run easy for six days; for a 5-K, only three easy days are needed.  For a marathon, 26 days seems like a long time, but I have found (also to my regret) that it is not too long at all for me.  Perhaps an elite runner, or even a talented runner, can get by with less recovery time, but not a mere mortal like I am.  I realized that it has been 27 days since my last marathon, and today I included in my 3-mile run some speed-work, for the first time - two 400-meter intervals.  "Wake up," I kept telling my stubborn legs!  They had been trained over a long period of time last fall to run long and slow, and it is always a slow process to begin to run fast again.  

How fast were those intervals?  Not very.  That's covered under another Rule of Thumb which I have also come to appreciate over the years, and which I remember I first saw on the back of an old codger's shirt on some long-ago Race Day:

"The older I  get, the faster I was."