by Duncan Larkin
The marathon world-record holder has struggled with injury.
by Duncan Larkin, Published Aug. 23, 2011, Updated Aug. 24, 2011 at 10:08 AM UTC
Over two hundred runners took part in the German study.
Start your FREE subscription to Competitor Digital today!
Get our monthly digital magazine, weekly running content & exclusive offers delivered to your inbox.
© 2014 Competitor Group Inc. All Rights Reserved