Japanese Journal of Community-based Comprehensive Physical Therapy
Online ISSN : 2758-0318
Original Articles
Reproducible measurement conditions for knee extensor strength using an inexpensive, simple manual muscle strength test: An investigation of inter- and intra-examiner reliability and absolute reliability using generalizability theory
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2023 Volume 2 Pages 21-30


Objective: The purpose of this study was to investigate the measurement conditions to ensure the accuracy and reliability of knee extensor muscle strength measurement as the effectiveness of a simple, inexpensive manual muscle strength meter.

Methods: Five physical therapists (three males and two females) measured knee extensor strength in healthy adults. The reliability indices were the intra- and interinspector reliability of each measurer and the measurement error, which is absolute reliability. The measurement conditions that ensure reliability were also calculated.

Results: The intra-examiner reliability [ICC (1.1)] was 0.88, 0.92, and 0.94 for male subjects, and 0.71 and 0.82 for female subjects. The inter-observer reliability [ICC (2.1)] was 0.36 for the five assayers, 0.89 for the male assayer, and 0.32 for the female assayer, with good values only for the male assayer. The reliability of the measurement was assured when the measurement was performed more than once by one person when the measurement was performed only by a male or female measurer, or more than three times by one person or more than two people when the measurement was performed regardless of gender.

Conclusion: An inexpensive simple manual muscle strength test can provide reliable results when used by male measurers.

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© 2023 Japanese Society of Community-based Comprehensive Physical Therapy

This is an open access article under the terms of the Creative Commons Attribution license (https://creativecommons.org/licenses/by/4.0/).
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