When the Fort Wadsworth cannon sounds on Nov. 4, propelling more than 47,000 marathon runners across the Verrazano-Narrows Bridge for the New York City Marathon, Jack Hirschowitz’s first strides will be charged by the steady pulse of three white spheres, looping like electrons orbiting around an invisible core.

 

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http://www.nytimes.com/2012/10/19/sports/joggling-the-marathon-3-beanbags-and-26-2-miles.html?ref=newyorkcitymarathon