In vivo neck musculo-tendinous stiffness in response to quick-releases

Abstract

This study was designed to assess musculo-tendinous stiffness of the head-neck segment in response to quick-release in flexion and extension. Musculo-tendinous stiffness of the neck was calculated using analysis of head kinematics with optimization procedure during the first 30 ms after the acceleration peak following the release at different exertion levels (20 % to 70 % MVC). Results showed a linear relationship between torque and musculo-tendinsous stiffness for flexion (R = 0.82, P < 0.5) and extension (R = 0.69, P < 0.05). Resultas shows also an increase of moment of inertia with torque. Correlation between stiffness and torque indicates that quick-release perturbations applied to the head associated with optimization procedure to assess head kinematics provide an attractive approach to investigate head-neck musculo-tendinous stiffness. In addition, changes noticed on head-neck moment of inertia shows that mechanical properties evaluated in this study could be altered by modifications of geometry of the corporal segment induced by exertion level. © 2010 International Federation for Medical and Biological Engineering.