Sample Protocol for Testing Muscle Tone, Paresis and Spasticity of the Biceps Brachii Muscle

Biceps Brachii Testing
Myotonometer® tone/compliance measurements are taken while the subjects’ muscles are relaxed and during a maximal voluntary contraction (MVC). It is recommended that at least 3 trials of 8 measurements each are taken. The area over the flexor surface of the arm is tested with the subject in a sitting position. The elbow is flexed to ninety degrees with the forearm supinated. The area of application of the Myotonometer® probe for the biceps is located (e.g. equidistant between the lateral aspect of the acromion process and the most inferior part of the olecranon). This point is marked with an ink pen. Measurements can then be taken with the muscle relaxed. For the contraction phase, subjects are instructed to perform a maximal isometric contraction (MVC) of the elbow flexors. To ensure limited movement of the extremity, a strap can be placed at the wrist for resistance. A hand‑held force dynamometer, placed at the distal aspect of the forearm, should be used to gauge the force of the isometric contraction of the upper extremity. For this protocol, subjects should reproduce similar force output for each trial during MVC testing.

Myotonometer® Measurement Procedures
The Myotonometer® contains a linear array of transducers that measure: 1) the amount of displacement of a probe as it is pushed onto the skin overlying the tested muscle and 2) the amount of force required per millimeter of tissue displacement. Measurements are taken every .25 kg of force up to 2.0 kg. Computational software generates force/displacement curves for each condition (relaxed; contracted). The percent difference at each .25 kg of force between the relaxed and contracted conditions can be computed. The smaller the difference in measurements between the two conditions, the more severe the spastic condition (figs 1-3). Percent difference scores correlate with the modified Ashworth scale but Myotonometer® measurements are more sensitive to smaller changes. In addition, this protocol will enable the clinician and researcher to determine the extent to which changes in muscle tone or paretic changes within a muscle contribute to a disability.

Sample Protocol for Testing of Muscle Injury or Muscle Imbalance