Knee pain - the most common symptom is diffuse peripatellar pain (vague pain around the kneecap) and localized retropatellar pain (pain focused behind the kneecap). Affected individuals typically have difficulty describing the location of the pain, and may place their hands over the anterior patella or describe a circle around the patella (the "circle sign").[1] Pain is usually initiated when load is put on the knee extensor mechanism, e.g. ascending or descending stairs or slopes, squatting, kneeling, cycling, running or prolonged sitting with flexed (bent) knees.[4][5][6] The latter feature is sometimes termed the "movie sign" or "theatre sign" because individuals might experience pain while sitting to watch a film or similar activity.[4] The pain is typically aching with occasional sharp pains and may present it self exacerbated.[1][7] Crepitus (joint noises)[4] may be present (but not have relation with pain and function)[8][9] Giving-way of the knee[4] may be reported Knee Flexion reduced - individuals with PFPS may show a knee flexion reduced during the activedes.[10]