October 2022

Quantification of the Forearm Muscles Mechanical Properties Using Myotonometer: Intra- and Inter-Examiner Reliability and Its Relation with Hand Grip Strength

Authors: Tülay Cevik Saldiran 1, Ilke Kara 1, 2, Seval Kutlutürk Yikilmaz 3


  1. Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Bitlis Eren University, Bitlis, Turkey
  2. Department of Physical Therapy and Rehabilitation, Institute of Health Sciences, Dokuz Eylul University, Izmir, Turkey
  3. Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Istanbul Medipol University, Istanbul, Turkey

Journal: Journal of Electromyography and Kinesiology - October 2022, In Press (DOI: 10.1016/j.jelekin.2022.102718)

  • Based on the study results, excellent intra and inter-examiner repeatabilities were found in using MyotonPRO to quantify FCU muscle tone, stiffness, and elasticity.
  • The evaluation of the mechanical properties of the forearm muscles with MyotonPRO will contribute to future studies in both research and clinical settings.

The primary objective of this study was to investigate the reliability of the myotonometer in the mechanical properties of the forearm muscles [m. extensor carpi radialis brevis (ECRB), and m. flexor carpi ulnaris (FCU)] in healthy individuals. The secondary objective was to investigate the relationship between the handgrip strength and mechanical properties of these forearm muscles.

The mechanical properties (muscle tone, stiffness, and elasticity) of the ECRB and FCU were measured using the MyotonPRO device. Examiner 1 performed two sets of measurements with a time interval of 30 minutes to determine intra-examiner reliability. Examiner 2 performed measurements during the interval between the two sets of examiner 1.

The intra- and inter-examiner reliabilities were excellent (ICC˃.82) for muscle tone, stiffness, and elasticity of the FCU. Both intra- and inter-examiner reliability in the evaluation of ECRB muscle tone, elasticity, and stiffness was moderate to excellent (ICCs= 0.56-0.98). The muscle tone and stiffness properties of the FCU were positively correlated with the handgrip strength (p<.05).

The study findings indicate that the MyotonPRO device is a reliable tool to quantify ECRB, and FCU muscles mechanical properties in healthy individuals.


Fig 1. The mechanical properties assessments of forearm muscles


Keywords: physiotherapy, biomechanics, strength, skeletal muscle, reliability study

In conclusion, the results of this research showed that the MyotonPRO is a reliable device for clinicians to quantify the mechanical properties of these forearm muscles, particularly FCU. In addition, the results of this study showed that individuals with higher grip strength had stronger forearm flexor muscle tone and stiffness estimations by myotonometer. Neverlethess, these study results are limited only to session repeatability, and day-to-day reliability still needs to be examined.