Runners

Participants in an amateur race approach the finish in Tel Aviv...Participants in an amateur "Running in Color" event approach the finish line of a five kilometre (three mile) race in Tel Aviv, November 14, 2014. Inspired by the Hindu Holi festival, the race involved participants running along a course dotted with locations where coloured powders were thrown over the runners. The event was held to raise awareness about Post Traumatic Stress Disorder caused by conflict in the country. REUTERS/Finbarr O'Reilly

Finbarr O'Reilly/Reuters

Racers in the five-kilometre “Running in Colour” event approach the finish line in Tel Aviv, Israel. Inspired by the Hindu Holi festival, coloured powders were thrown over runners during the event, which was held to raise awareness about post traumatic stress disorder.

A runner falls in front of ''Miura'' fighting bulls during the running of the bulls, at the San Fermin festival, in Pamplona, Spain, Monday, July 14, 2014. Revelers from around the world arrive to Pamplona every year to take part in some of the eight days of the running of the bulls.

Alvaro Barrientos/AP

A runner falls in front of Miura fighting bulls during the running of the bulls at the San Fermin festival, in Pamplona, Spain, on Monday

Runners and riders in the parade ring before the Albany Stakes during Day Four of the 2014 Royal Ascot Meeting at Ascot Racecourse, Berkshire

David Davies/PA

Runners and riders in the parade ring before the Albany Stakes during Day Four of the 2014 Royal Ascot Meeting at Ascot Racecourse, Berkshire

Competitors run in the Badwater Ultramarathon in Death Valley National Park

Lucy Nicholson/Reuters

Competitors take part in the Badwater Ultramarathon in Death Valley National Park, California, in temperatures that can reach 55 degrees centigrade

A fighting cow leaps over revellers upon entering the bullring following the first running of the bulls of the San Fermin festival in Pamplona...A fighting cow leaps over revellers upon entering the bullring following the first running of the bulls of the San Fermin festival in Pamplona July 7, 2013. Several runners suffered light injuries in a run that lasted four minutes and six seconds, according to local media.   REUTERS/Joseba Etxaburu (SPAIN - Tags: ANIMALS SOCIETY)

Joseba Etxaburu/Reuters

A fighting cow leaps over revellers upon entering the bullring following the first running of the bulls of the San Fermin festival in Pamplona, Spain, on Sunday. Several runners suffered light injuries in a run that lasted four minutes and six seconds, according to local media