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Neuromuscular patterns of the lower leg during step-downs in elderly fallers and nonfallers
Abstract
While various chronic diseases and medication use have been associated with an increased risk of falling, neuromuscular deficits, due to aging or pathology, have been strongly implicated in the etiology of falls. In particular, it has been suggested that inadequate pre-innervation can result in impact forces large enough to cause femoral neck fractures, thereby leading to a fall. Less dramatically, inadequate pre-innervation may lead to an inability to compensate for potentially destabilizing forces occurring on impact. Unfortunately, little is known about the neuromuscular activation patterns present among fallers. Neuromuscular patterns were examined between 12 elderly male fallers (mean age = 74.75) and 12 elderly males (mean age = 72.75), with no history of falling. Falling status was verified through hospital records, physician's records, or spousal interview. Fallers had experienced at least one fall during the prior year, while nonfallers had no history of falling during the prior year. All subjects were free from any known neurological disorders. Neuromuscular patterns were assessed, via EMG, over three days. A step-down task was performed from heights of 10, 20, and 30 centimeters, during sighted and unsighted conditions. In addition, balance was assessed via the stork stand, tandem walk, Romberg, and get-up-and-go tests; while various strength measurements were assessed via dynamometer or EMG. The results indicate the following: (1) Fallers had significantly slower movement time than nonfallers and were more likely to display a polyphasic pre-innervation EMG pattern; (2) Fallers had significantly shorter pre-innervation times during step-downs from 10 and 20 centimeter, but this distinction failed to hold during step-downs from 30 centimeters; (3) Fallers performed more poorly on all tests of balance; (4) No statistically significant group difference could be found on any strength measure or anthropometric assessment. Consequently, in the present study population, falling status appears to be related to a slowing of the neuromuscular system. Unfortunately, the specifics or nature of that slowing remain obscure.
Subject Area
Cellular biology|Public health
Recommended Citation
Patras, Liz Ann, "Neuromuscular patterns of the lower leg during step-downs in elderly fallers and nonfallers" (1997). Doctoral Dissertations Available from Proquest. AAI9721484.
https://scholarworks.umass.edu/dissertations/AAI9721484