Document Type


Publication Date



Purpose. Age-associated muscle weakness, postural instability, and orthostatic hypotension have been identified as contributing factors to falls , but the relationships among them are not clear. Therefore, the purpose of this study, a two-way factorial design, was to investigate the differences in lower extremity (LE) muscle activity, blood pressure (BP), and heart rate (HR) between young and older individuals in an upright position. Methods. Ten young males (20-24 yrs.) and 10 older males (65-82 yrs.) stood for 15 minutes while BP, HR, and LE electromyography (EMG) were recorded at one minute intervals . A two-way ANOVA was used for data analysis , p=.05. Results. Mean arterial pressure of both groups significantly increased from supine values within one minute of standing (young = 86.5±1.68 to 96.9±3.16 mmHg, old = 100.3±4.42 to 114.0±5.40 mmHg). BP variables remained elevated during the 15 minutes of standing despite a significantly attenuated HR response in the older group (young = 85±4.51 bpm, old = 73±3.98 bpm). Standing EMG activity of the older group was significantly greater than the young group. Conclusion. This study suggests that increased LE muscle activity may play a role in the ability of older individuals to maintain BP in the standing position.


This article was originally published in Clinical Kinesiology, volume 60, issue 2, in 2006.

Peer Reviewed



American Kinesiotherapy Association



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.