Ashis Roy, 81, adds a half marathon to his bag of 115

India's marathon man Ashis Roy added another half marathon to his bag of 115 full marathons as he completed his 11th 13-mile run in the San Francisco marathon 2013.

Clocking a time of 3 hours and 37 minutes, the 81-year-old cardiologist, the oldest participant in the marathon, clipped five minutes from his last run in Alexandria, Virginia, three weeks back.

Roy, a resident of Delhi's Chittaranjan Park, who ran his 115th marathon in Mumbai in January, has switched over to running half marathons since a spinal injury in November 2011 that required major surgery to fix six nails in his last two vertebrae.

A retired wing commander of the Indian Air Force, Roy took to running marathons at the age of 52 and by 75 he had completed 82 races. He went on to complete his 100th marathon in January 2010.

Roy plans to participate in the Philadelphia marathon with his 42-year old daughter in September.