A runner clutching his painful knee on a sunlit road during outdoor training, with a red highlight emphasizing joint pain, strain and acute sports injury while stopping midstride.

runner athlete knee pain injury running sport fitness training jogging marathon road pavement sidewalk outdoor exercise motion movement strain sprain ache discomfort joint muscle leg healthcare medical physiotherapy rehabilitation recovery therapy inflammation treatment rest endurance sweat posture balance warmup stretching prevention performance competition apparel focus grimace remedy urgency mobility