Publications

• MyotonPRO is easy, adaptable, and highly manageable, and performs passive measurements.
• MyotonPRO is able to estimate the strength of the main muscle groups of the lower limb.

Context: The assessment of strength is one of the most usual practices among professionals involved in health care or sport. Quadriceps and hamstrings are the most commonly assessed muscle groups. Generally, the methods used to assess muscle strength are active and, therefore, alternative passive methods could be useful. MyotonPRO provides measures on 3 mechanical properties of the muscle: tone, elasticity, and stiffness.

Objective: This study aimed to analyze the association of MyotonPRO, an easy-to-use tool not requiring voluntary stimulus from the subject, with strength values in quadriceps and hamstrings.

Study Design: Experimental.

Setting: University kinesiology laboratory.

Participants: Thirty-eight recreational athletes were evaluated.

Main Outcome Measures: Anthropometric and demographic data, MyotonPRO-based measures of vastus lateralis, rectus femoris, vastus medialis, biceps femoris, and semitendinosus, and the maximum voluntary isometric contraction of quadriceps and hamstrings.

Procedures: The association was examined using multiple regression models to estimate strength through MyotonPRO-based parameters and different patient characteristics. The models encompassed either 2 or 3 independent variables.

Results: The adjusted R2 values for predicting quadriceps strength were .666 for rectus femoris, .726 for vastus lateralis, and .667 for vastus medialis, while in regard to hamstrings, they were .617 for biceps femoris and .604 for semitendinosus.

Conclusions: The main finding was that acceptable relationships were found between muscle strength and MyotonPRO-based parameters when variables such as gender and/or age are considered. Our study reveals a new tool for estimating strength with outstanding advantages: it is easy, time-efficient, adaptable, and highly manageable through the feasible equations provided.

Figure 1. Measurement of the quadriceps (A) and hamstrings (B) through the MyotonPRO.

Keywords: strength assessment, clinimetrics, muscle strength, estimation equations

Our study provides several research and clinical implications. First, it reveals a new tool for estimating strength with outstanding advantages: it is easy, adaptable, and highly manageable through the feasible equations provided, and health- and/or sports-related professionals can therefore estimate the strength of the main muscle groups of the lower limb as of parameters from one of the muscles encompassed in the muscle group, interchangeably. Furthermore, the use of MyotonPRO may have a fundamental impact on time efficiency which is of paramount importance since time constraints represent one of the cornerstones of work stress in different professional spheres and healthcare environments. Moreover, a concise spreadsheet is attached as Supplementary Material (available online) to ease the estimation of strength measures through the implementation of MyotonPRO parameters and 2 covariables (sex and/or age). Second, usual and traditional methods require active participation of the subject, whereas subjects are frequently unable to perform a MVIC of the muscle and, furthermore, the health status of several patients in clinical settings requires evaluation solely under passive circumstances. Therefore, MyotonPRO could have potential practical applications for any professional who wants to estimate quadriceps and hamstring strength without an active effort from the subject.