Reliability and validity of the damping coefficient in a damped harmonic oscillator model during a medial drop landing in subjects with functional ankle instability

We propose a damped harmonic oscillator model of the acceleration of the center of mass during a medial drop landing to measure dynamic stability in subjects with functional ankle instability. We found construct validity of the model to be good. The damping coefficient in the model significantly correlated with measures of static stability; however the trial-to-trial reliability of the damping coefficient was weak and not significant.