78YEARS OLD MAN KNOCKED DOWN BY EXPLOSION STILL COMPLETED THE BOSTON MARATHON

Bill Iffrig, 78, lies on the ground as police officers react to a second explosion (circled) at the finish line of the Boston Marathon 

A 78-year-old runner who was knocked down by the first of two bombs that hit the Boston Marathon has become an internet sensation after he got up and finished the race. 

Bill Iffrig, who was competing in his third Boston Marathon, was yards from the finish line when the explosion was detonated. Video and pictures from the scene show Mr Iffrig, in bright orange vest, having his legs swept out from under him by the blast, but with the help of a race official who lifted him to his feet, he got up and kept going, determined to reach his goal. 

The runner's son, Mark Iffrig, of Seattle, told The Associated Press he was tracking his father's race progress online and didn't realize what had happened until he went on Facebook to post about his dad finishing the race. He quickly turned on the TV and called his dad.
"It's horrible. He said it was quite a concussive blast. He was a little dazed. Someone helped him up," said Mark Iffrig , adding he recognized his father from a widely distributed Boston Globe photo showing him on the ground, surrounded by police officers and race officials. "He was only about 10 feet from the finish line."
Iffrig said his father is an avid runner who has raced in a number of marathons.
"He's a hell of a runner," he said. "He's run a lot and he's fast."
Reports in the US media say that Iffrig, a retired builder from Washington state, took up running in the 1970s so he could stay fit enough for mountain climbing. He is an accomplished runner, and in 2009 was named the Washington Herald's Man of the Year in Sports.
After recovering from the blast Mr Iffrig walked a further half a mile to his hotel.