Sporadic inclusion body myositis: pilot study on the effects of a home exercise program on muscle function, histopathology and inflammatory reaction.

Objective: To evaluate the safety and effect of a home training program on muscle function in 7 patients with sporadic inclusion body myositis.

Design: The patients performed exercise 5 days a week over a 12-week period.

Methods: Safety was assessed by clinical examination, repeated muscle biopsies and serum levels of creatine kinase. Muscle strength was evaluated by clinical examination, dynamic dynamometer and by a functional index in myositis.

Results: Strength was not significantly improved after the exercise, however none of the patients deteriorated concerning muscle function. The histopathology was unchanged and there were no signs of increased muscle inflammation or of expression of cytokines and adhesion molecules in the muscle biopsies. Creatine kinase levels were unchanged. A significant decrease was found in the areas that were positively stained for EN-4 (a marker for endothelial cells) in the muscle biopsies after training.

Conclusion: The home exercise program was considered as not harmful to the muscles regarding muscle inflammation and function. Exercise may prevent loss of muscle strength due to disease and/or inactivity.