|Reid, Kieran - Jean Mayer Human Nutrition Research Center On Aging At Tufts University|
|Price, Lori - Tufts - New England Medical Center|
|Harvey, William - Tufts - New England Medical Center|
|Driban, Jeffrey - Tufts - New England Medical Center|
|Hau, Cynthia - Jean Mayer Human Nutrition Research Center On Aging At Tufts University|
|Fielding, Roger - Jean Mayer Human Nutrition Research Center On Aging At Tufts University|
|Wang, Chenchen - Tufts - New England Medical Center|
Submitted to: Arthritis and Rheumatology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/2015
Publication Date: 12/18/2015
Citation: Reid, K.F., Price, L.L., Harvey, W.F., Driban, J.B., Hau, C., Fielding, R.A., Wang, C. 2015. Muscle power is an independent determinant of pain and quality of life in knee osteoarthritis. Arthritis and Rheumatology. 67(12):3166-3173. doi: 10.1002/art.39336.
Interpretive Summary: A greater understanding of the role of lower extremity muscle function in knee osteoarthritis (OA) is of critical importance. Such knowledge has the potential to accelerate the development of more effective preventive and treatment interventions that may ultimately reduce the significant personal and societal impact of this painful, debilitating and highly prevalent disease. The purpose of this study was, for the first time, to comprehensively examine the relationships between lower extremity muscle power and perceived disease severity in a large population of patients with knee osteoarthritis. Our overall findings demonstrated that dynamic leg muscle power was an independent determinant of knee pain and quality of life in patients with knee osteoarthritis. Muscle strength was not a major determinant of perceived disease severity. This study suggests that, compared to traditional measures of muscle function such as muscle strength, muscle power is a more definitive and important measure of muscle performance for understanding disease biology in knee OA. The novel findings of this study also support the future examination of resistance training interventions specifically targeting the improvement of lower extremity muscle power, and their associated impact on pain and quality of life measures, in persons with symptomatic knee osteoarthritis.
Technical 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 32.77.2 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). CONCLUSION: 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.