Rock the Marathon

Once shunned by serious marathon runners, digital devices that monitor speed, distance and heart-rate have crept into acceptance by many of the 37,000 runners who will compete in next Sunday’s New York City Marathon. The New York Times reports that Lance Armstrong, the seven-time Tour de France champion, will wear Nike+ shoes with sensors made to send data about his pace to his iPod
nano, and  Dino Farfante will carry an MP3 player and, strapped to his arm,
a G.P.S. unit made by his company, MotionLingo, that gives oral updates
on his speed. The most popular device, the Times reports, may be the simple MP3 player, which runners find provides distraction and motivation. According to the Times, MP3s are also being used in novel ways to improve technique.
Ideally a runner, to be most efficient, should take short quick steps —
about 180 a minute. The Times cites Jenny Hadfield, a coach of 16 years and the author of "Marathoning for Mortals", who advises her runners to download the tick tock of a metronome
to their MP3s to stay in step.