OBJECTIVES: To show the superiority of eccentric versus concentric strengthening in terms of improving quadriceps strength in knee osteoarthritis (OA), a randomized controlled study was conducted to perform 12 sessions of either eccentric or concentric isokinetic muscle strengthening over 6 weeks. METHODS: We recruited males and females, aged between 40 and 70 years, with predominantly unilateral femorotibial OA. Exclusion criteria were having a prosthesis, inflammatory arthritis or flare-up of OA, symptomatic patellofemoral OA, cardiovascular or pulmonary disease that could be a contraindication to the study treatment, and any pathology that could cause muscle weakness. The primary endpoint was the between-group difference in change in maximum concentric isokinetic knee extension peak torque (PT) at 60 degree/s on the OA side at 6 weeks. Secondary endpoints were between-group difference in change in concentric hamstring PT at 60 degree/s; eccentric quadriceps and hamstring PT at 30 degree/s; 10 m and 200 m walking speeds; pain and functional status (WOMAC score) at 6 weeks and 6 months. RESULTS: The sample consisted of 11 females and 27 males, with a mean age of 57.7 +/- 7.52 years and a body mass index (BMI) of 25.95 +/- 3.93 kg/m2. Quadriceps strength increased more at 6 weeks in the concentric than the eccentric group with no statistical difference. There was a rate of 25% major adverse events in the eccentric group. CONCLUSIONS: Eccentric training resulted in a smaller improvement in quadriceps strength than concentric training and was associated with a high risk of muscle injury, particularly to the hamstring muscles.

Full text (sometimes free) may be available at these link(s):      help

• PubMed Central
• DOI
• PubMed
• PDF locator
• publisher