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14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT)

17.06. - 21.06.2019, Berlin

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Inhibitory effects of prolonged vibratory stimulus on the maximal voluntary contraction force and muscle activity of the triceps brachii

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  • presenting/speaker Rikiya Shirato - Hokkaido Bunkyo University, Eniwa, Japan
  • Yuka Yamanaka - Saiseikai Otaru Hospital, Otaru, Japan

International Federation of Societies for Surgery of the Hand. International Federation of Societies for Hand Therapy. 14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT). Berlin, 17.-21.06.2019. Düsseldorf: German Medical Science GMS Publishing House; 2020. DocIFSHT19-1070

doi: 10.3205/19ifssh1491, urn:nbn:de:0183-19ifssh14915

Published: February 6, 2020

© 2020 Shirato et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.

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Objective: Muscle co-contraction is recognized as an important cause of the loss of elbow motion. In clinical practice, muscle guarding of the triceps brachii is often observed to cause elbow co-contraction with the biceps brachii and brachialis. Local vibration is widely used for the reduction of muscle tonus. The purpose of this study was to quantify the effects of prolonged vibratory stimulus on the maximal voluntary contraction (MVC) force and muscle activity of the triceps brachii, and to clarify the effective stimulus time.

Materials and Methods: Twenty-five healthy university students with a mean age of 21.4 years participated. Vibratory stimuli at 86 Hz was applied to the triceps brachii tendon for 5 and 10 minutes. Before and after these stimuli, the elbow extension MVC force was measured using a hand-held dynamometer. Muscle activities of the lateral, long and medial heads of the triceps brachii were also recorded by surface electromyography.

Results: The median MVC force significantly decreased to 82.7% after 5 minutes vibratory stimulus and to 83.3% after 10 minutes vibratory stimulus (P < .001). The median percentage of integrated electromyography (%IEMG) of the triceps also significantly decreased to 78.2 (lateral head), 83.8 (long head), 81.5 (medial head) after 5 minutes vibratory stimulus and to 77.7, 81.4, 77.2, respectively, after 10 minutes vibratory stimulus (P < .001). There were no differences in the decrease in the MVC force and %IEMG between 5 and 10 minutes vibratory stimulus (P > .05).

Conclusions: Prolonged vibratory stimulus (5 minutes) to the triceps brachii tendon appeared to have an inhibitory effect on MVC force and muscle activity. The present results suggest that prolonged vibratory stimulus could be an effective treatment capable of reducing muscle guarding of the triceps brachii.