Affiliations: [a] Laboratoire Interactions Posture, Mouvement,
Hôpital Rothschild (APHP), Paris, France | [b] Institut de Recherche Biomédicale des Armées,
Brétigny-sur-Orge, France | [c] Université Pierre et Marie Curie, Paris 6, Paris, France | [d] EAC CNRS 4396, Université Paris – Est
Créteil, Créteil, France
Note: [] Address for correspondence: Pierre Portero, Laboratoire
Interactions Posture, Mouvement, Hôpital Rothschild (APHP), 33 boulevard de
Picpus, 75571 Paris Cedex 12, France. Tel.: +331 40 19 30 97; Fax: +331 40 19
30 62; E-mail: p.portero@rth.aphp.fr
Abstract: This study was designed to assess the reproducibility of head-neck
musculo-tendinous stiffness (HMS) findings of the head-neck segment in response
to quick-release in flexion and extension. The HMS was expressed as the slope
of the isometric torque-angular displacement curve of the head-neck segment
derived from the first 15 ms from the peak acceleration following release at
different exertion levels (10% to 80% MVC). A test--retest methodology (7 days interval)
was performed to assess the measurement reproducibility. The results showed a
linear relationship between the flexion and extension torque and angular
displacement (0.94 < R^{2} < 0.99).
Moreover, HMS findings evidenced good to excellent reproducibility using
relative (ICC) as well as absolute (SEM) parameters. It was concluded that that
simple kinematic assessment was appropriate for investigating HMS.
Nevertheless, multiple-segmentation of the head-neck segment could lead,
according to exertion level, to geometrical changes after the release.
Keywords: Musculo-tendinous stiffness, reproducibility, quick-release, head kinematics, muscle strength
