as all good biologists, psychologists and steve prefontaine (sarah jessica is to manolo blahniks as "pre" was to adidas) worth their teaspoon of sodium chloride know, there is a beginning and an end. a single venture into maximum heart rate, lactic threshold, and chafing"bits", can thus be seen as the recapitulation of a double helix of the human sojourn-- or toothless and encopretic, to dentures and encopretic, plus every movement in between.
fresh babies are pretty much incapable of anything beyond wriggling around dressed up in pumpkin/pea pod/gerbera daisy outfits and emptying their bowels. the novice runner is all too familiar with the latter function, when at mile 2, anal dilation is imminent, and the pre-run poo becomes routine ever after. learning to navigate in a forward motion, without tripping or falling on your backside, is the same beginning for toddlers and trainees alike.
the growth spurt to adolescence, at mile two-and-some-change (for the fellow 10-ish minute mile club) is evidenced in a clumpy gait and an all consuming obsession with how your shadow looks "retarded", especially when furtively trying to pull one short leg (it's always just the one side) from a perspiring crotch, or doing a two step roundhouse kick to coax it back down an equally sweaty thigh.
people who complain that they hate running are either my sedentary, fine wine and stinky cheese appreciating younger sibling, or those that give up after 15 minutes. contrary to what teen cosmo journalista's would have us believe, the first is always the worst, most painful, growing pain-y, whitehead pustule mile of any run; it is for your body. the next ones are for your mind, soul, and justifying that large oreo blizzard.
finally a comfortable cruising pace is found, where creeping clothing is ignored, thoughts of richter scale cellulite jiggle are expunged, and breathing no longer sounds like a middle aged asthmatic watching the spice channel from his treadmill. these are your 30's.
and the final stretch to the last lampost is typically completed under the "zimmer frame and orthotics" category.