INTERMUSCULAR COORDINATION DURING FAST CONTACT CONTROL LEG TASKS IN MAN

Citation
Cam. Doorenbosch et al., INTERMUSCULAR COORDINATION DURING FAST CONTACT CONTROL LEG TASKS IN MAN, Brain research, 751(2), 1997, pp. 239-246
Citations number
32
Categorie Soggetti
Neurosciences
Journal title
ISSN journal
00068993
Volume
751
Issue
2
Year of publication
1997
Pages
239 - 246
Database
ISI
SICI code
0006-8993(1997)751:2<239:ICDFCC>2.0.ZU;2-G
Abstract
From previous inverse dynamic analyses of human leg extensions, it was hypothesized that the underlying processes for the activation of mono - and biarticular muscles are different; the mono-articular muscles be ing activated when they shortened, whereas the biarticular muscles app eared responsible for the control of the external force direction. In the present study, experiments were performed on a dynamometer which w as especially developed to test this hypothesis. Subjects had to exert different prescribed force vectors on a moving force-plate during leg extension, which they had intensively practised prior to the actual e xperiments. Of each trial, position, force and EMG activity were recor ded. Net joint torques were calculated by the method of inverse dynami cs and related to the EMG-patterns of the mono- and biarticular upper leg muscles to reveal whether the previously observed different roles in contact tasks might constitute a general principle in motor control . The results showed that although the action of the biarticular m. re ctus femoris and hamstrings muscles was consistent in controlling the direction of the external force, the actions of the mono-articular mus cles did not agree with their hypothesized role as simple work generat ors. The generalizability of a different control for mono-and biarticu lar muscles could thus not be confirmed for these tasks. They might ra ther reflect one out of more available strategies the CNS can use to c ontrol different contact control tasks.