Short range stiffness elastic limit depends on joint velocity

Short range stiffness elastic limit depends on joint velocity

De Vlugt, E.
Van Eesbeek, S.
Baines, P.
Hilte, J.
Meskers, C.G.M.
De Groot, J.H.

Mechanical, Maritime and Materials Engineering

Biomechanical Engineering

2011-07-01

Muscles behave as elastic springs during the initial strain phase, indicated as short range stiffness (SRS). Beyond a certain amount of strain the muscle demonstrates a more viscous behavior. The strain at which the muscle transits from elastic- to viscous-like behavior is called the elastic limit and is believed to be the result of breakage of cross-bridges between the contractile filaments. The aim of this study was to test whether the elastic limit, measured in vivo at the wrist joint, depended on the speed of lengthening. Brief extension rotations were imposed to the wrist joint (n=8) at four different speeds and at three different levels of voluntary torque using a servo controlled electrical motor. Using a recently published identification scheme, we quantified the elastic limit from measured joint angle and torque. The results showed that the elastic limit significantly increased with speed in a linear way, indicating to a constant time of approximately 30 ms before cross-bridges break. The implications for movement control of the joint are discussed.

short range stiffness
joint stiffness
muscle
cross-bridges
elastic limit
model
identification

http://resolver.tudelft.nl/uuid:81429406-446a-4701-9c21-9a82ebaca171

https://doi.org/10.1016/j.jbiomech.2011.05.022

Elsevier

0021-9290

Journal of Biomechanics, 44 (11), 2011

Institutional Repository

journal article

(c) 2011 Elsevier