Table 1 Efficacy of hip joint musculature strengthening in subjects with patellofemoral pain syndrome

	Mascal *et al*13	Tyler *et al*38	Boling *et al*41
Type of study	2 case reports	Cohort study	Pre-/post-test intervention study
Groups	2 patients with PFPS, exhibiting weak hip abductors, extensors and external rotators	1 group—35 PFPS patients, mean (SD) age 35 (16) years (29 women, 6 men) demonstrating hip flexion, abduction and adduction weakness	Group 1—14 PFPS patients
Groups			Group 2—14 control subjects
Treatment	Physical therapy once or twice weekly for 14 weeks plus HEP. Weeks 0–6 involved non-WB exercises, abdominals and isometric hip exercises. Weeks 6–10 involved WB exercises, isometric and dynamic exercises in single leg stance. Weeks 10–14 involved functional training	6 week treatment programme-consisted of OKC and CKC strengthening and flexibility exercises for hip musculature. Hip flexors, abductors, adductors and extensors were progressively strengthened. Stretching in Ober and Thomas test positions as well as self performed stretches	6 week progressive weight bearing rehabilitation programme, with emphasis on hip joint abductor and quadriceps strengthening. 3 sessions per week (1 supervised session and 2 self directed sessions)
Outcome measures	Functional status questionnaire, VAS worst pain, hip and abdominal strength, observational gait analysis, step down task, 3 dimensional kinematics of lower extremity	Hip flexion, abduction and adduction strength, Thomas and Ober tests, VAS for pain on ADLs as well as on exercise (treatment success defined as a min of 1.5 cm reduction of pain on each VAS)	Pain as measured on a VAS. FIQ. VMO and VL EMG onsets. Gluteus medius EMG onset
Results	Significant reduction in pain, improved lower extremity kinematics, ability to return to original level of function	Hip flexion strength improved by 35%, improvements in hip abduction and adduction strength, increased flexibility, significant decrease in VAS scores	VMO and VL onset timing differences, as well as VAS and FIQ scores improved in group 1 subjects. Post-test scores for group1 were equivalent to those in group 2

ADL, activities of daily living; CKC, closed kinetic chain; EMG, electromyogram; FIQ, Functional Index Questionnaire; HEP, home exercise programme; OKC, open kinetic chain; PFPS, patellofemoral pain syndrome; VAS, Visual Analogue Scale; VL, vastus lateralis; VMO, vastus medialis oblique; WB, weight bearing.