Table 1.

Methodological Quality Assessment Questions & Scoring

Methodological Quality Assessment Questions	Scored Positive if:
1. Did the study address an appropriate and clearly focused question?	Research question or hypothesis was that females with PFPS have decreased hip muscle force or endurance compared with healthy controls.
2. Was the study population clearly defined?	The place of recruitment, age and activity level were given.
3. Was patellofemoral pain syndrome clearly defined?	PFPS participants completed a reliable, valid scale responsive in this specific population. The intensity and history of symptoms was clearly documented.
4. Was the method of patellofemoral pain syndrome assessment reported?	The following information was described: Localization and activities associated with symptoms of females with PFPS Exclusion criteria Experience and profession of the clinical investigator
5. Were the females with PFPS representative of the target population?	The participants were females, actives, between 18 and 35 years of age.
6. How comparable are the females with PFPS and healthy controls with respect to potential confounding factors?	Age and activity level are comparable between both groups. Strength or endurance were normalized to body weight.
7. Were the same exclusion criteria used for both females with PFPS and healthy controls?	The exclusion criteria were described and similar for both groups.
8. Was the method of hip muscle strength or endurance assessment reported?	Body position, type of fixation and instrument used, numbers of trials, order of testing sequences, verbal encouragement, dynamometer placement, measurement units and warm‐up were documented.
9. Was the same method of assessment for both females with PFPS and healthy controls?	The same method of strength or endurance assessment was used for both groups.
10. Were the assessors blinded to the different groups?	Blinded application of strength or endurance assessments was performed.

Abbreviations: PFPS=patellofemoral pain syndrome.