December: Agility

   The day after a brutal workout, you wake stiff as dried glue. With a little early morning padding around, flexibility grudgingly returns, even if you still feel sore and creaky. Stretching would have prevented this torture, right?

   This is both common wisdom and a typical scold you'll hear from know-it-all runners. Stretching assumes a religious magnitude with many athletes. It's freely prescribed for arthritic knees, pulled quads, tendonitis, and all manner of afflictions for which it does absolutely no good. It brings pleasure, both in the act of doing it and in the suppleness that results from a limber body. We assume that it ought to be good for us. Unfortunately, there's very little science to support this.

   For all the scrutiny devoted to the biomechanics of running and other athletic endeavor, we know very little about stretching. There are coaches who advise against it. Some studies have shown that pulled hams and ripped tendons are more likely to result from stretching than from running. Particularly bad are deep-knee bends, the hurdler's stretch, the yoga plow, and various ballet contortions.

   Certain techniques are bad, as well. Ballistic stretching, in which you pull a muscle to its limit, then gently bob on it, is a recipe for injury. Almost any kind of fast or forceful stretch is a no-no. Cold muscles resist stretching and are more likely to tear than limber muscles. And arbitrary range-of-motion goals (touch nose to knee while sitting with legs extended, for example) ignore the unique architecture of your very special body. Anti-stretching advocates will tell you there are world-class marathoners who can't touch their toes.

   So why bother at all? Quite obviously, stretching increases your range of motion, boosting the efficiency of movement. Hamstrings, for example, tend to shorten with distance training. Shortened hamstrings resist every lift of the knee. They sap energy, demanding more effort with every step. Stretching them saves effort. Agility is efficient.

   Then there's the business of pain, especially after a very hard workout. General soreness is caused by lactic acid and other waste products that build up in the muscles. When you stretch, blood rushes deep into the tissue, washing away these by-products.

   But then, a deliberate cooldown at the end of your workout seems to have the same effect. Let's not kid ourselves: scientific reasons for stretching are beside the point. The real benefit is pleasure. My father, a student and lifelong lover of stretching, believed pleasure was both its payoff and its defining technique. Deep into his sixties, he'd end an evening splayed out on the living-room floor, pulling hams and shoulders, groaning in bliss (he recommended groaning).

   There's no shortage of books or trainers who will show you specific stretches to try, all well and good. But be wary of advice that tries to boil the art into science. Remember that stretching is a movement, not a position. It should be slow and fluid. It should stop when it becomes painful. Let pleasure guide you.