Reliability and validity of electrogoniometry measurement of lower extremity movement

Abstract

Objectives: To establish the reliability, accuracy and concurrent validity of electrogoniometers for measuring extreme lower extremity movements.

Study design: Reliability, accuracy and validity study.

Methods: This project employed two experiments. Investigation I determined electrogoniometer accuracy compared to a digital protractor. Investigation II compared electrogoniometers to a criterion measure, motion analysis, in sagittal plane dance movements in 17 dancers. Intraclass correlation coefficients (ICC) and standard error of measurement (SEM) were calculated for hip, knee, and ankle sagittal plane angular displacements.

Results: In Investigation I, electrogoniometer to protractor correlations were high (r ≥ 0.998, SEM ≤3.65°). In Investigation II, instrument and intra-rater reliability correlations were high (r ≥ 0.983 and r ≥ 0.972, SEM ≤ 3.49° and ≤4.48°), as were concurrent validity correlations (r ≥ 0.949, SEM ≤6.80°) to motion analysis.

Conclusions: This error may be acceptable for lower extremity studies with extreme movements when motion capture is unavailable.

Keywords:

• Measurement error
• Motion analysis
• Hip
• Knee
• Ankle
• Dance

Acknowledgements

The advice provided by Ellen C. Ross is gratefully acknowledged. We'd also like to thank Jon Spriggs for technical assistance and Les Mayers for reviewing this manuscript.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.