My dear mom (rest her soul) would say the picture at left looks like my closet floor, circa 1979. I always kept my well-worn running shoes around way too long, she thought, and they were often those bright-colored Nikes with the knobby waffle-iron soles. In the poyester-leisure-suit 1970s, running itself came out of the closet -- by decade's end it was a genuine fad. More than 30 years later the sport has gone in and out of style. Running gear has permeated the pop-culture fashion spectrum (even if it's often worn by unlikely dorks like Ben Stiller's character in The Royal Tenenbaums or Big Pussy in The Sopranos). The ranks of marathoners (and racers at all distances) has exploded; the New York City Marathon had 2,090 entrants in 1976 and 37,866 in 2006. Cashing in on all this is the running-apparel industry, which has fueled the sport's growth with inventive ads and flashy imagery (and, occasionally, great design as well).