Physical performance tests are useful for evaluating and monitoring the severity of locomotive syndrome

Abstract

Background: The concept of the locomotive syndrome (LS), first proposed in Japan in 2007, has become widely accepted, and the 25-question Geriatric Locomotive Function Scale (GLFS-25), a quantitative, evidence-based diagnostic tool for LS, has been developed. However, the association between the GLFS-25 score and the outcome of physical capacity tests has never been investigated. Furthermore, which physical tests are good indices for evaluating and monitoring the severity of locomotive syndrome have not been identified. In addition, the impact of knee and low back pain on locomotive syndrome is unclear. The purpose of this study is to confirm the validity of GLFS-25 by demonstrating its significant correlation with the outcome of physical function tests and to determine which tests are good indicators for monitoring the severity of LS. The secondary aim of the project is to investigate how much influence knee and low back pain may have on the LS of the middle-aged and elderly.

Methods: A total of 358 subjects were drawn from a general health checkup in a rural area of Japan. We measured back muscle strength, grip strength, one-leg standing time with eyes open, 10-m gait time, timed up-and-go test, maximum stride, functional reach, height, weight, % body fat and bone mineral density, and we obtained a visual analog scale of low back pain and knee pain. The degree of the locomotive syndrome was evaluated using the GLFS-25. Associations of all the variables with the GLFS-25 score were analyzed using both univariate and multivariate analyses.

Results: The GLFS-25 score was significantly higher in females than in males in both the total and in the age older than 60 years groups. The GLFS-25 score showed a significant positive correlation with age (r = 0.360), knee pain (r = 0.576), low back pain (r = 0.526), timed up-and-go test (r = 0.688) and 10-m gait time (r = 0.634), and it showed a significant negative correlation with one-leg standing time with eyes open (r = -0.458), maximum stride (r = -0.408), functional reach test (r = -0.380), back muscle strength (r = -0.364) and grip strength (r = -0.280). Multiple regression analysis indicated that knee pain (β = 0.282), low back pain (β = 0.304), one-leg standing time (β = -0.116), timed up-and-go test (β = -0.319) and back muscle strength (β = -0.090) were significantly associated with the GLFS-25 score. Grip strength (β = -0.99) was a good substitute for back muscle strength in the multiple regression analysis.

Conclusions: We confirmed the validity of GLFS-25 by demonstrating a significant correlation and association of its score with the outcome of a series of functional performance tests. One-leg standing time with eyes open, timed up-and-go test and grip strength proved to be easy, reliable and safe performance tests to evaluate and monitor an individual's severity of LS as a complement to the GLFS-25. We also proved that knee and low back pain significantly impact the degree of LS.