title: Persons with chronic hip joint pain exhibit reduced hip muscle strength.
abstract: METHODS
  Controlled laboratory cross-sectional study. Objectives To assess strength differences of the hip rotator and abductor muscle groups in young adults with chronic hip joint pain (CHJP) and asymptomatic controls. A secondary objective was to determine if strength in the uninvolved hip of those with unilateral CHJP differs from that in asymptomatic controls.
  
  
  BACKGROUND
  Little is known about the relationship between hip muscle strength and CHJP in young adults.
  
  
  METHODS
  Thirty-five participants with CHJP and 35 matched controls (18 to 40 years of age) participated. Using handheld dynamometry, strength of the hip external rotators and internal rotators was assessed with the hip flexed to 90° and 0°. To assess external rotator and internal rotator strength, the hip was placed at the end range of external rotation and internal rotation, respectively. Strength of the hip abductors was assessed in sidelying, with the hip in 15° of abduction. Break tests were performed to determine maximum muscle force, and the average torque was calculated using the corresponding moment arm. Independent-sample t tests were used to compare strength values between (1) the involved limb in participants with CHJP and the corresponding limb in the matched controls, and (2) the uninvolved limb in participants with unilateral CHJP and the corresponding limb in the matched controls.
  
  
  RESULTS
  Compared to controls, participants with CHJP demonstrated weakness of 16% to 28% (P<.01) in all muscle groups tested in the involved hip. The uninvolved hip of 22 subjects with unilateral CHJP demonstrated weakness of 18% and 16% (P<.05) in the external rotators (0°) and abductors, respectively, when compared to the corresponding limb of the matched controls.
  
  
  CONCLUSIONS
  The results of the present study demonstrate that persons with CHJP have weakness in the hip rotator and hip abductor muscles. Weakness also was found in the uninvolved hip of persons with CHJP.
authors.affiliation: Program in Physical Therapy, Washington University School of Medicine, St Louis, MO.
authors.forename: Marcie
authors.initials: M
authors.lastname: Harris-Hayes
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mueller
authors.forename: Shirley A
authors.initials: SA
authors.lastname: Sahrmann
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Bloom
authors.forename: Karen
authors.initials: K
authors.lastname: Steger-May
authors.forename: John C
authors.initials: JC
authors.lastname: Clohisy
authors.forename: Gretchen B
authors.initials: GB
authors.lastname: Salsich
mesh_terms: D000328:Adult; D002908:Chronic Disease; D005260:Female; D006621:Hip Joint / Q000503:physiopathology*; D006801:Humans; D008297:Male; D018908:Muscle Weakness / Q000175:diagnosis*; D059352:Musculoskeletal Pain / Q000209:etiology / Q000503:physiopathology*; D016059:Range of Motion, Articular; D055815:Young Adult
keywords: abductor; dynamometry; external rotator; femoroacetabular impingement; internal rotator