Do knees survive the Comrades Marathon?

Objective: To detect by magnetic resonance imaging (MRI) the presence and type of knee injuries in non-professional runners after running an ultra-marathon, and to determine whether ultra-marathon running exacerbates pre-existing knee injuries or results in new permanent injuries.

Design: A prospective MRI study of one knee of 10 randomly selected participants who completed the Comrades Marathon between 1997 and 2002. Their knees were scanned 48 hours before the race, and 48 hours and 1 month after the race.