Publications
Myotonometry and extended field-of-view ultrasound imaging allow reliable quantification of patellar tendon stiffness and length at rest and during maximal load, whereas several restrictions exist for the Achilles tendon
Authors: Florian Wegener 1, Arne Ritterbusch 1, Christian Saal 1, Christian Baumgart 2, Matthias W. Hoppe 3
Affiliations:
- Movement and Training Science, Faculty of Sport Science, Leipzig University, Leipzig, Germany
- Department of Movement and Training Science, Faculty of Humanities and Social Sciences, University of Wuppertal, Wuppertal, Germany
- Department of Exercise Science, Institute of Sport Science and Motology, Faculty of Educational Sciences, Philipps University of Marburg, Marburg, Germany
Journal: Frontiers in Sports and Active Living - May 2024, Volume 6, Article no. 1379506 (DOI: 10.3389/fspor.2024.1379506)
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Field & Applications:
- Reliability
- Validity
Introduction: Stiffness and length are well-established tendon parameters in sports and medicine. Myotonometry and ultrasound imaging are the commonly used methods to quantify these parameters. However, further studies are needed to clarify the reliability of these methods, especially when assessing maximally loaded tendons and when conducted by different experienced investigators. This study aimed to determine the intra- and interrater reliabilities of measuring the stiffness and length of the patellar tendon (PT) and Achilles tendon (AT) using the myotonometry method and the extended field-of-view ultrasound (EFOV-US) technique at rest and maximal load performed by different experienced investigators.
Methods: Twenty-seven participants were examined on three different days by one experienced investigator and one novice investigator. Primary outcomes were the intraclass correlation coefficient (ICC) and associated 95% confidence interval (95% CI), coefficient of variation (CV), standard error of measurement (SEM), and minimal detectable change (MDC) across the measurement days and investigators.
Results: For PT measurements at rest and maximal load, the estimated ICCs for stiffness and length were ≥.867 and ≥.970, respectively, with 95% CIs ranging from poor (.306) to excellent (.973) and good (.897) to excellent (.999). The CV, SEM, and MDC for PT stiffness and length were ≤5.2% and ≤2.0%, ≤39.3 N/m and ≤0.9 mm, and ≤108.9 N/m and ≤2.6 mm, respectively. For AT measurements, some restrictions were evident for stiffness at rest and both parameters at maximal load. However, regarding AT length at rest, the estimated ICC was ≥.996, with an excellent 95% CI (.987–.999). The CV, SEM, and MDC for AT length at rest were 2.8%, ≤1.1 mm, and ≤2.9 mm, respectively.
Conclusion: The estimated ICCs show good to excellent reliability for the myotonometry method and the EFOV-US technique for measuring PT stiffness and length at rest and maximal load for experienced and novice investigators. However, some restrictions are evident for the AT, especially for measurements at maximal load.
Keywords: MyotonPRO, digital palpation device, panoramic, technology, strain, properties, in vivo, novice
The estimated ICCs show good to excellent reliability for the myotonometry method with MyotonPRO and the EFOV-US technique for measuring PT stiffness and length at rest and maximal load for experienced and novice investigators. However, some restrictions are evident for the AT, especially for measurements at the maximal load. More research to clarify the validity and influence of the load magnitude is needed.