Running is rarely associated with acute injuries (muscle injuries, ankle sprain, ruptures of the Achilles tendon). More than 80% of the complaints are due to overuse injuries, mainly concerning knee, foot and Achilles tendon. Risk factors are high-performance sports, high training quantity, rapid increase of training intensity, previous injuries, and skeletal axis malalignment. Running is not suitable for severely overweight people and those with significant skeletal malalignment, dysplastic hips, spondylolisthesis, or cartilage damage.