Inclusion criteria:
Amateur athletes with regular sports activity at least 2h per day 3 times per week
Age between 18 and 40 years
Anterior knee pain for at least 3 month, aggravated with at least 1 activities such as stair descending, squatting, kneeling or prolonged sitting
Positive Clark test
Gastrocnemius tightness in affected side by Silfverskiöld test
VAS ≥ 30 mm in first assessment
Kujala questionnaire score < 85 of 100
Exclusion criteria:
Knee osteoarthritis, patellar tendonitis, bursitis or infrapatellar fat pad
Patellar fracture or dislocation history
Referred pain from lumbar, hip or ankle
Bilateral anterior knee pain
Previous surgery in affected lower limb
Contraindications of dry needling such as cardiovascular and coagulation disease, anticoagulation therapy, pregnancy, cancer, fear of needles
Physical therapy for knee pain within the previous 3 months
Genu valgum, genu varum, genurecurvatum and flat foot in affected limb