title: Muscular co-contraction covaries with task load to control the flow of motion in fine motor tasks.
abstract: This study focuses on the relationship between movement-time fluctuations in fine motor tasks and changing levels of muscular co-contraction. Based on a recent neuromotor noise theory, we expected that increased task stress would increase muscular co-contraction and prolong movement times. Ten right-handed adults performed a graphic task, which elicited local movement-time prolongations. In half the trials, a distracting sound was presented as an external stressor. Besides pen-tip kinematics, two estimates of muscular co-contraction were obtained from the surface EMG measurements of eight arm and hand muscles. The results confirm the presumed co-variation of movement time and co-contraction. We conclude that muscular co-contraction forms a strategic means to adapt the flow of motion to central information processing demands.
authors.affiliation: Nijmegen Institute for Cognition and Information, University of Nijmegen, P.O. Box 9104, 6500 HE Nijmegen, The Netherlands. r.meulenbroek@nici.kun.nl
authors.forename: Ruud G J
authors.initials: RG
authors.lastname: Meulenbroek
authors.forename: Gerard P
authors.initials: GP
authors.lastname: Van Galen
authors.forename: Majken
authors.initials: M
authors.lastname: Hulstijn
authors.forename: Wouter
authors.initials: W
authors.lastname: Hulstijn
authors.forename: Gijs
authors.initials: G
authors.lastname: Bloemsaat
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001288:Attention; D004576:Electromyography; D005260:Female; D007839:Functional Laterality; D006225:Hand / Q000502:physiology; D006801:Humans; D008297:Male; D008606:Mental Processes; D009048:Motor Skills / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D013647:Task Performance and Analysis