Document Detail

Stereotypic muscle-torque patterns are systematically adopted during acquisition of a multi-articular kicking task.
MedLine Citation:
PMID:  9802781     Owner:  NLM     Status:  MEDLINE    
Motor-control mechanisms used to learn multi-joint (kinematically indeterminate) movements, which involve the control of intersegmental dynamics, are poorly understood, because the few kinetic studies which examined them studied only a few trials performed early and late in learning. Therefore, we examined changes in movement kinematics and kinetics accompanying multi-joint movement acquisition to address the following questions: Once subjects can produce accurate movements, do motor patterns (i.e. net muscle torques) change with further learning? Are motor patterns learned using a systematic strategy? Following learning, are the same motor patterns consistently used for movement production? Subjects performed 16 blocks of 16 trials of a discrete weighted (mass = 1.674 kg) kicking movement, involving hip, knee, and ankle motion. They attempted to perform 400 ms spatially accurate movements. Kinematics were recorded for the hip, knee, ankle, and toe of the kicking leg, and inverse dynamics were used to obtain net-muscle-torque profiles. Subjects did not adopt the motor patterns initially used to produce accurate movements. With further learning, net muscle torques became less variable both within and between blocks; inter-joint dependency of muscle torques increased, as evidenced by decreased variability in the pair of muscle torques which directly affect a segment's motion (i.e. hip-knee and knee ankle muscle torques); and inter-joint relationships of muscle torques became more phase-locked, with hip and knee torques being produced simultaneously, as were knee and ankle torques. As there was a progression across blocks until the preferred motor patterns were adopted, the learned stereotypic motor patterns were systematically selected.
R P Young; R G Marteniuk
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of biomechanics     Volume:  31     ISSN:  0021-9290     ISO Abbreviation:  J Biomech     Publication Date:  1998 Sep 
Date Detail:
Created Date:  1999-01-29     Completed Date:  1999-01-29     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0157375     Medline TA:  J Biomech     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  809-16     Citation Subset:  IM; S    
Department of Kinesiology, University of Waterloo, Ontario, Canada.
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MeSH Terms
Joints / physiology*
Learning / physiology
Leg / physiology*
Motor Activity / physiology*
Muscle, Skeletal / physiology*
Psychomotor Performance / physiology

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