| Torque history of electrically stimulated human quadriceps: implications for stimulation therapy. | |
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MedLine Citation:
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PMID: 8423515 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The time course of knee extension torque was measured in human quadriceps muscles during 30 min of transcutaneous neuromuscular electrical stimulation (NMES). Ninety subjects were divided into six experimental groups (n = 15 per group), which received stimulation at one of the following frequency/duty cycle combinations: 10 Hz/50%, 30 Hz/50%, 50 Hz/50%, 10 Hz/70%, 30 Hz/70%, and 50 Hz/70%. Two-way analysis of variance revealed that the magnitude of the relative torque decrease (the percentage of decrease in torque relative to the initial value) was significantly different between frequencies (p < 0.005) and duty cycles (p < 0.02), with no significant interaction (p > 0.6). Increasing either frequency or duty cycle caused a greater decrease in torque. In spite of this result, there was no significant difference between groups in the total activity (torque-time integral) achieved during the 30 min treatment session. The magnitude of this activity corresponded to only about 7-14 maximum voluntary contractions. Finally, the average torque during the treatment session was significantly different among groups (p < 0.001), being greatest for the 50 Hz/50% group and least for the 10 Hz/70% group. Taken together, these data suggest that a smaller number of longer duration contractions produces the greatest muscle tension. They also suggest that the absolute torque levels achieved with NMES are relatively low compared with voluntary muscular activity. |
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Authors:
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R L Lieber; M J Kelly |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Journal of orthopaedic research : official publication of the Orthopaedic Research Society Volume: 11 ISSN: 0736-0266 ISO Abbreviation: J. Orthop. Res. Publication Date: 1993 Jan |
Date Detail:
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Created Date: 1993-02-23 Completed Date: 1993-02-23 Revised Date: 2004-11-17 |
Medline Journal Info:
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Nlm Unique ID: 8404726 Medline TA: J Orthop Res Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 131-41 Citation Subset: IM |
Affiliation:
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Department of Orthopaedics, Veterans Administration Center, San Diego, California. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Analysis of Variance Electric Stimulation Electric Stimulation Therapy* Humans Knee Joint Muscles / physiology* Neuromuscular Junction / physiology Time Factors |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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