caa a22 4500 463245377 CHVBK 20180405153324.0 cr unu---uuuuu 170326e20070301xx s 000 0 eng 10.1007/s00422-006-0120-6 doi (NATIONALLICENCE)springer-10.1007/s00422-006-0120-6 A model of open-loop control of equilibrium position and stiffness of the human elbow joint [Elektronische Daten] [Dinant Kistemaker, Arthur Van Soest, Maarten Bobbert] According to the equilibrium point theory, the control of posture and movement involves the setting of equilibrium joint positions (EP) and the independent modulation of stiffness. One model of EP control, the α-model, posits that stable EPs and stiffness are set open-loop, i.e. without the aid of feedback. The purpose of the present study was to explore for the elbow joint the range over which stable EPs can be set open-loop and to investigate the effect of co-contraction on intrinsic low-frequency elbow joint stiffness (K ilf). For this purpose, a model of the upper and lower arm was constructed, equipped with Hill-type muscles. At a constant neural input, the isometric force of the contractile element of the muscles depended on both the myofilamentary overlap and the effect of sarcomere length on the sensitivity of myofilaments to [Ca2+] (LDCS). The musculoskeletal model, for which the parameters were chosen carefully on the basis of physiological literature, captured the salient isometric properties of the muscles spanning the elbow joint. It was found that stable open-loop EPs could be achieved over the whole range of motion of the elbow joint and that K ilf, which ranged from 18 to 42 N m·rad−1, could be independently controlled. In the model, LDCS contributed substantially to K ilf (up to 25 N m·rad−1) and caused K ilf to peak at a sub-maximal level of co-contraction. Springer-Verlag, 2006 Kistemaker Dinant Institute for Fundamental and Clinical Human Movement Sciences, IFKB, Vrije Universiteit, Van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands aut Van Soest Arthur Institute for Fundamental and Clinical Human Movement Sciences, IFKB, Vrije Universiteit, Van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands aut Bobbert Maarten Institute for Fundamental and Clinical Human Movement Sciences, IFKB, Vrije Universiteit, Van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands aut Biological Cybernetics Springer-Verlag 96/3(2007-03-01), 341-350 0340-1200 96:3<341 2007 96 422 https://doi.org/10.1007/s00422-006-0120-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00422-006-0120-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kistemaker Dinant Institute for Fundamental and Clinical Human Movement Sciences, IFKB, Vrije Universiteit, Van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- Van Soest Arthur Institute for Fundamental and Clinical Human Movement Sciences, IFKB, Vrije Universiteit, Van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- Bobbert Maarten Institute for Fundamental and Clinical Human Movement Sciences, IFKB, Vrije Universiteit, Van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands aut NATIONALLICENCE 773 0- Biological Cybernetics Springer-Verlag 96/3(2007-03-01), 341-350 0340-1200 96:3<341 2007 96 422 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer