title: Muscle Power Is an Independent Determinant of Pain and Quality of Life in Knee Osteoarthritis.
abstract: OBJECTIVE
  This study examined the relationships between leg muscle strength, power, and perceived disease severity in subjects with knee osteoarthritis (OA) in order to determine whether dynamic leg extensor muscle power would be associated with pain and quality of life in knee OA.
  
  
  METHODS
  Baseline data on 190 subjects with knee OA (mean ± SD age 60.2 ± 10.4 years, body mass index 32.7 ± 7.2 kg/m(2) ) were obtained from a randomized controlled trial. Knee pain was measured using the Western Ontario and McMaster Universities Osteoarthritis Index, and health-related quality of life was assessed using the Short Form 36 (SF-36). One-repetition maximum (1RM) strength was assessed using the bilateral leg press, and peak muscle power was measured during 5 maximum voluntary velocity repetitions at 40% and 70% of 1RM.
  
  
  RESULTS
  In univariate analysis, greater muscle power was significantly associated with pain (r = -0.17, P < 0.02) and also significantly and positively associated with SF-36 physical component summary (PCS) scores (r = 0.16, P < 0.05). After adjustment for multiple covariates, muscle power was a significant independent predictor of pain (P ≤ 0.05) and PCS scores (P ≤ 0.04). However, muscle strength was not an independent determinant of pain or quality of life (P ≥ 0.06).
  
  
  CONCLUSIONS
  Muscle power is an independent determinant of pain and quality of life in knee OA. Compared to strength, muscle power may be a more clinically important measure of muscle function within this population. New trials to systematically examine the impact of muscle power training interventions on disease severity in knee OA are particularly warranted.
authors: Tufts University, Boston, Massachusetts.
authors: Kieran F
authors: KF
authors: Reid
authors: Tufts Medical Center and Tufts University, Boston, Massachusetts.
authors: Lori Lyn
authors: LL
authors: Price
authors: Tufts Medical Center and Tufts University, Boston, Massachusetts.
authors: William F
authors: WF
authors: Harvey
authors: Tufts Medical Center and Tufts University, Boston, Massachusetts.
authors: Jeffrey B
authors: JB
authors: Driban
authors: Tufts University, Boston, Massachusetts.
authors: Cynthia
authors: C
authors: Hau
authors: Tufts University, Boston, Massachusetts.
authors: Roger A
authors: RA
authors: Fielding
authors: Tufts Medical Center and Tufts University, Boston, Massachusetts.
authors: Chenchen
authors: C
authors: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology / Q000503:physiopathology; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D010146:Pain / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000502:physiology / Q000503:physiopathology*; D011788:Quality of Life