The aim of this study was to configure a force assessment device and determine potential testing protocols for quantitative evaluation of human neck muscles. The study design consisted of non-randomized control trials, with repeated measures; data from 12 normal subjects were obtained. Several apparatuses were designed, constructed and tested, i.e. single or short trains of supramaximal stimuli were used to activate sternocleidomastoid muscles in a seated position with strain gauges (6.2% variability with double-pulse stimulations) or in a supine position with load cells (5.2% variability with similar activation). Using a final configuration, maximum elicited peak forces were 1742 ± 323 g for single-pulse and 3976 ± 484 g for double-pulse stimulations (n = 12). There were no significant differences in maximum recorded peak torques between sessions per individual. Yet, detectable muscle activities were simultaneously recorded in the contralateral sternocleidomastoid muscles. This non-invasive, quantitative assessment approach has novel value for determining treatment efficacy, disease progression, and/or relative distribution of muscle strength in patients with abnormal neck muscle function.
Bibliographical noteFunding Information:
We would like to thank Gary Williams for his assistance with computer programming and LabVIEW expertise; Monica Mahre for assistance with the manuscript preparation; and all the subjects for their participation and patience. This work was supported in part by the Center for Muscle and Muscle Disorders and the Biomedical Engineering Institute at the University of Minnesota.