Different Method, Different Results?

Abstract

To the Editor: I read with great interest the article by Daubney and Culham entitled “Lower Extremity Muscle Force and Balance Performance in Adults Aged 65 Years and Older” (December 1999). After reading the article and reviewing the data presented, I found several sections of the article that lead me to question the authors' results and conclusions. According to their own data, the 3 measures of balance—the Berg Balance Scale (BBS), the Timed Get Up & Go Test (GUG), and the Functional Reach Test (FRT)—failed to yield significant differences between subjects with a history of falling and subjects without a history of falling (Tab. 1). Intuitively, that result would suggest either that (1) the measures were not valid for the population being tested or (2) the authors' assumption that there is a relationship between balance and the incidence of falling is not valid. In either case, these measures should not have been used, because they failed to detect significant differences between the groups. If the muscle testing methods showed a difference between groups, what would that mean? From the initial question, I went on to investigate the methodology and findings for the measurements of muscle force, which provoked several more questions. Why were of all the muscle groups tested in the midrange of joint motion? The principles of biomechanics and exercise physiology clearly dictate that the maximal force of the muscles in question would have been best tested in the position of function, standing, or at 90 degrees to the joint axis. In addition, and perhaps most perplexing, is why the authors performed all the tests with the subjects positioned supine. Logically, if you want to determine the relationship of muscle force to the 3 tests of standing balance, then the muscle force measurements should be performed in a standing …