Effect of back muscle strength and sagittal spinal imbalance on locomotive syndrome in Japanese men.

The Japanese Orthopaedic Association has proposed the term locomotive syndrome to designate a condition of individuals in high-risk groups with musculoskeletal disease who are highly likely to require nursing care. This study investigates the influence of spinal factors on locomotive syndrome in Japanese men. A total of 105 men older than 50 years were enrolled in the study. Those answering yes to least 1 of 7 categories in a self-assessment checklist for locomotive syndrome were defined as having locomotive syndrome. The authors evaluated lateral lumbar radiographs, sagittal parameters, sagittal balance using the spinal inclination angle as an index, spinal range of motion as determined with SpinalMouse (Idiag, Volkerswill, Switzerland), back muscle strength, and body mass index. Age, back muscle strength, and spinal inclination angle significantly correlated with locomotive syndrome. Multiple logistic regression analysis indicated that a decrease in back muscle strength (odds ratio, 0.964; P<.01) and an increase in spinal inclination angle (odds ratio, 1.232; P<.05) were significantly associated with locomotive syndrome. Back muscle strength had significant negative correlations with age and spinal inclination angle. Spinal inclination angle had significant negative correlations with back muscle strength and lumbar and total spinal range of motion and significant positive correlations with age, body mass index, sacral slope angle, and lumbar kyphosis. A decrease in back muscle strength and an increase in spinal inclination angle may be the most important risk factors for locomotive syndrome in Japanese men. Back muscle strengthening and spinal range of motion exercises could be useful for improving the symptoms of locomotive syndrome.