istock Joint jarring run 512749663
istock You've got to break down before you can build up 512749703
istock Pushing herself to the limit 512693631
istock Suffering through this trail run 512698441
istock Run off your heels 512698489
istock Wearing down the cartilage 512698403
istock Playing through the pain 512753571
istock Taking her game, and the pain, up a notch 512698415
istock Pinpointing the pressure 512698361
istock No sprain no gain! 512698375
istock Stretch...and avoid injury 512698393
istock Running through the pain and inflammation 512627653
istock Taking on the trail one knee at a time 512749661
istock Feeling too much of the burn 512749693
istock Joint pain slowing you down? 512698371
istock Suffering from knee pain 512698379
istock Running through the pain 512698353
istock Keep your eye on the prize! - Fitness Goals 512698433
istock Make the pain drive you 512698435
istock Competing through the pain 512698427
istock Running through the strain 512698351
istock knee pain 525725938
istock Fitness Girl Stretching 533700636
istock Stretch and avoid injury 533700718
istock Stretching 533700802
istock Stretching 534048704
istock Stretch and avoid injury 537703962
istock Stretching 533844178
istock Stretch and avoid injury 537703890
istock Stretch and avoid injury 528635258