The Utility of Myotonometry in Musculoskeletal Rehabilitation and Human Performance Programming

Abstract

Myotonometry is a relatively novel method used to quantify the biomechanical and viscoelastic properties (stiffness, compliance, tone, elasticity, creep, and mechanical relaxation) of palpable musculotendinous structures with portable mechanical devices called myotonometers. Myotonometers obtain these measures by recording the magnitude of radial tissue deformation that occurs in response to the amount of force that is perpendicularly applied to the tissue through a device's probe. Myotonometric parameters such as stiffness and compliance have repeatedly demonstrated strong correlations with force production and muscle activation. Paradoxically, individual muscle stiffness measures have been associated with both superior athletic performance and a higher incidence of injury. This indicates optimal stiffness levels may promote athletic performance, whereas too much or too little may lead to an increased risk of injury. Authors of numerous studies suggested that myotonometry may assist practitioners in the development of performance and rehabilitation programs that improve athletic performance, mitigate injury risk, guide therapeutic interventions, and optimize return-to-activity decision-making. Thus, the purpose of our narrative review was to summarize the potential utility of myotonometry as a clinical tool that assists musculoskeletal clinicians with the diagnosis, rehabilitation, and prevention of athletic injuries.

Keywords: clinical decision-making; muscle stiffness; performance optimization.

Figure 1

A, Clinician acquiring measures from the rectus femoris muscle using the MyotonPRO (Myoton AS) digital palpation device. B, Cross-sectional illustration of the rectus femoris muscle and surrounding tissues with the MyotonPRO lowered into proper measurement range. Measurement process for the MyotonPRO: (1) A, Operator places the probe on the belly of a superficial skeletal muscle. (2) B, Operator lowers the device into the measurement range, identified by illumination of a green light on the device. (3) The device initiates a quick (15-ms) and light (0.4-N) mechanical impulse force. (4) The tissue responds to the impulse with damped oscillation that is registered via the device accelerometer. (5) The tone, biomechanical, and viscoelastic properties are simultaneously computed by the device (Table 1). Images and measurement process description used with permission from Aleko Peipsi, CEO, Myoton AS.

Figure 2

Stiffness continuum denoting a theoretical relationship between athletic performance and the injury risk.