Prosthetics/orthotics/devices
Myotonometer Intra- and Interrater Reliabilities1

https://doi.org/10.1016/S0003-9993(03)00006-6Get rights and content

Abstract

Leonard CT, Deshner WP, Romo JW, SuojaES, Fehrer SC, Mikhailenok EL. Myotonometer intra- andinterrater reliabilities. Arch Phys Med Rehabil 2003;84:928–32.

Objectives:

To assess the intra- and interrater reliabilities of the Myotonometer®, a hand-held, computerized, electronic device that quantifies muscle stiffness (tone/compliance).

Design:

Reliability study.

Setting:

Research laboratory.

Participants:

Thirty-five healthy, nondisabled adults (age range, 22–42y).

Interventions:

Not applicable.

Main Outcome Measures:

Two raters used the Myotonometer to evaluate subjects’ lateral gastrocnemius and biceps brachii muscles. Muscles were measured in a relaxed state and during a voluntary isometric contraction. Coefficients were calculated for each muscle and each condition (relaxed, contracted). Results were analyzed by using Design II intraclass correlation coefficients.

Results:

Reliability coefficients were highest when the instrument exerted moderate to strong forces against the muscle (range, 0.50–2.00kg; intrarater reliability R range, .84–.99; interrater reliability R range, .75–.96).

Conclusions:

Myotonometer measurements had high to very high intra- and interrater reliabilities for measurements of the lateral gastrocnemius and biceps brachii muscles.

Section snippets

Methods

All procedures were approved by the University of Montana Institutional Review Board for Use of Human Subjects and conformed to the Helsinki Declaration.

Myotonometer Force/Displacement Recordings

A total of 60 measurements were taken for each subject, 30 for the biceps brachii and 30 for the lateral gastrocnemius. Displacement measurements for the relaxed biceps brachii muscle ranged from 2.94mm at .25kg to 12.41mm at 2.00kg, whereas displacement for the contracted biceps brachii ranged from .38mm at .25kg to 9.18mm at 2.0kg. Displacement measurements for the relaxed lateral gastrocnemius muscle ranged from 1.92mm at .25kg to 11.19mm at 2.00kg, whereas displacement of the contracted

Discussion

Myotonometer measurements had very high intra- and interrater reliabilities for testing of isometrically contracted muscles and high to very high intra- and interrater reliabilities for testing of relaxed muscles. The exception was moderate reliability of measurements at the lowest force level of measurement (.25kg).

Hand-held and computerized isokinetic dynamometry provide more quantifiable muscle strength data than does the MMT. A summary of 18 studies that examined hand-held dynamometry

Conclusion

The Myotonometer is a reliable instrument for assessing muscle stiffness, tone, and compliance of the relaxed or contracted biceps brachii and lateral gastrocnemius muscles of nondisabled subjects. Its speed and ease of use approaches that of hand-held dynamometry. Myotonometer measurements provide quantifiable data that are not influenced by confounding variables such as tester strength, clinical experience of the tester, subject pain at high force levels, and muscle substitutions.

Acknowledgements

We gratefully acknowledge the technical assistance of Pamela Diedrich, Motor Control Research Laboratory, University of Montana, and Kathleen Miller, PhD, University of Montana, for statistical design assistance.

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