Both peripheral and central nervous system sensitization, clinically referred to as pain sensitization can result can be an enhanced, persistent and more widespread pain response. Recent studies have found the presence of increased pain sensitivity at remote sites, enhanced temporal summation and hypersensitivity to various stimuli to be associated with reports of more severe knee pain symptoms. These studies are cross-sectional and although they link signs of sensitization with greater levels of pain and disability they cannot infer causality.