title: Activity patterns of extrinsic finger flexors and extensors during movements of instructed and non-instructed fingers.
abstract: The fingers of the human hand cannot be controlled fully independently. This phenomenon may have a neurological as well as a mechanical basis. Despite previous studies, the neuromechanics of finger movements are not fully understood. The aims of this study were (1) to assess the activation and coactivation patterns of finger specific flexor and extensor muscle regions during instructed single finger flexion and (2) to determine the relationship between enslaved finger movements and respective finger muscle activation. In 9 healthy subjects (age 22-29), muscle activation was assessed during single finger flexion using a 90 surface electromyography electrode grid placed over the flexor digitorum superficialis (FDS) and the extensor digitorum (ED). We found (1) no significant differences in muscle activation timing between fingers, (2) considerable muscle activity in flexor and extensor regions associated with the non-instructed fingers and (3) no correlation between the muscle activations and corresponding movement of non-instructed fingers. A clear disparity was found between the movement pattern of the non-instructed fingers and the activity pattern of the corresponding muscle regions. This suggests that mechanical factors, such as intertendinous and myofascial connections, may also affect finger movement independency and need to be taken into consideration when studying finger movement.
authors.affiliation: Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, The Netherlands.
authors.forename: Nathalie
authors.initials: N
authors.lastname: van Beek
authors.affiliation: Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, The Netherlands; Donders Institute, Department of Neurology and Clinical Neurophysiology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Dick F
authors.initials: DF
authors.lastname: Stegeman
authors.affiliation: Biomedical Signals and Systems, MIRA Institute, University of Twente, Enschede, The Netherlands; Department of Rehabilitation medicine, VU University Medical Center, Amsterdam Movement Sciences, The Netherlands.
authors.forename: Josien C
authors.initials: JC
authors.lastname: van den Noort
authors.affiliation: Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, The Netherlands; Department of BioMechanical Engineering, Delft University of Technology, Delft, The Netherlands.
authors.forename: DirkJan
authors.initials: D
authors.lastname: H E J Veeger
authors.affiliation: Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, The Netherlands. Electronic address: h.maas@vu.nl.
authors.forename: Huub
authors.initials: H
authors.lastname: Maas
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D005385:Fingers / Q000502:physiology*; D006801:Humans; D008297:Male; D009068:Movement; D018482:Muscle, Skeletal / Q000502:physiology*
keywords: Coactivation; EMG; Kinematics; Muscle compartmentalization; Neuromuscular control