Architectural Ultrasound Pennation Angle Measurement of Lumbar Multifidus Muscles: A Reliability Study.

UNLABELLED

The pennation angle has been shown to be a relevant parameter of muscle architecture. This parameter has not previously been measured in the lumbar multifidus musculature, and it is for this reason that it has been considered of great interest to establish an assessment protocol to generate new lines of research in the future.

OBJECTIVE

The objective of this study was to establish a protocol for measuring the pennation angle of the multifidus muscles, with a study of intra-rater and interrater reliability values.

DESIGN

This was a reliability study following the recommendations of the Guidelines for Reporting Reliability and Agreement Studies (GRRAS).

SETTING

The study was carried out at University of Alcalá, Department of Physiotherapy.

SUBJECTS

Twenty-seven subjects aged between 18 and 55 years were recruited for this study.

METHODS

Different ultrasound images of the lumbar multifidus musculature were captured. Subsequently, with the help of ImageJ software, the pennation angle of this musculature was measured. Finally, a complex statistical analysis determined the intra- and interrater reliability.

RESULTS

The intra-rater reliability of the pennation angle measurement protocol was excellent for observer 1 in the measurement of the left-sided superficial multifidus 0.851 (0.74, 0.923), and for observer 2 in the measurement of the right-sided superficial 0.711 (0.535, 0.843) and deep multifidus 0.886 (0.798, 0.942). Interrater reliability was moderate to poor, and correlation analysis results were high for thickness vs. pennation angle.

CONCLUSIONS

The designed protocol for ultrasound measurement of the pennation angle of the lumbar multifidus musculature has excellent intra-rater reliability values, supporting the main conclusions and interpretations. Normative ranges of pennation angles are reported. High correlation between variables is described.