Table 1 Participant eligibility criteria

Inclusion criteria

 • Aged 18–40 years

 • Reported insidious (non-traumatic) onset of anterior or retropatellar knee pain

 • Pain on two or more of the following activities: prolonged sitting, kneeling, squatting, running, patella palpation, hopping, stair walking, stepping down or isometric quadriceps contraction

 • Peak hip abduction torque values [33]: Females [18–29 years] ≤ 94.1 Nm; Females [30–39 years] ≤ 75.8 Nm; Males [18–29 years] ≤ 144.1 Nm; Males [30–39 years] ≤ 139 Nm

Exclusion criteria

 • Presence of inflammatory arthritis; knee pain referred from the hip or lumbar spine; any history of significant knee surgery; other causes of knee pain such as, but not restricted to: meniscal pathologies, quadriceps tendon injuries, patella tendinopathy, tibial tubercle apophysitis; bursitis

 • Received any treatment within the last 3 months including physiotherapy, podiatry etc.