title: Soleus H-reflex gain in healthy elderly and young adults when lying, standing, and balancing.
abstract: Soleus Hoffman-reflex (H-reflex) gain was compared at the same background level of electromyographic activity across lying, natural standing, and tandem stance postures, in 12 young and 16 elderly adults. When compared to a lying posture, young adults significantly depressed soleus H-reflex gain when in a natural standing (19% decrease) and a tandem stance position (30% decrease; p <.0125 for both positions). For elderly adults, there was no significant decrease in H-reflex gain while standing naturally, but there was a significant 28% decrease when performing tandem stance (p <.0125). The data indicate that, although the mild motor control challenge of natural standing does not induce a decrease in soleus H-reflex gain in the elderly adults, as it does in young adults, in the more difficult task of tandem stance, soleus H-reflex gain is significantly decreased in both young and elderly adults.
authors.affiliation: Department of Physical Education, Health and Recreation, Western Washington University, Bellingham 98225-9067, USA. chalmers@cc.wwu.edu
authors.forename: Gordon R
authors.initials: GR
authors.lastname: Chalmers
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Knutzen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology; D000704:Analysis of Variance; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology; D011187:Posture; D011336:Probability; D011446:Prospective Studies; D012018:Reflex / Q000502:physiology*; D012680:Sensitivity and Specificity