Weight Loss Impacts Leg Muscle, Strength in Knee OA

(HealthDay News) – In patients with osteoarthritis (OA) of the knee, a 16-week low-energy diet program results in independent losses of leg muscle tissue and strength, and is accompanied by improvements in body mass-normalized muscle strength, according to research published in the February issue of Arthritis & Rheumatism.

Marius Henriksen, P.T., Ph.D., of the Copenhagen University Hospital in Denmark, and colleagues used dual X-ray absorptiometry and isometric muscle strength testing to evaluate the effects of a 16-week low-energy diet-induced weight loss program on knee muscle strength and lower-extremity muscle mass. Participants included 159 obese patients with knee OA.

The researchers found that the patients lost an average of 12.9kg, including 10.9kg fat mass, 3.8kg of which was leg fat mass. The total lean body mass decreased by 1.9kg, including 0.785kg leg lean mass. After weight loss, absolute muscle strength reduced by approximately 3–4%, and there was an 11–12% increase in body mass-normalized muscle strength. Leg lean mass was significantly correlated with muscle strength at baseline, but there was no correlation at follow-up.

“Low-energy diet-induced weight loss led to independent losses of leg muscle tissue and strength. The weight loss was accompanied by increased normalized muscle strength along with improved disability and pain — all of which are beneficial for patients with knee OA. The present findings suggest that weight loss in knee OA patients should be combined with efforts to restore or add muscle mass,” the authors write.

The study was partially funded by the Cambridge Weight Plan.

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