title: EMG-force relations during isometric contractions of the first dorsal interosseous muscle after stroke.
abstract: OBJECTIVE
  This study examines the electromyogram (EMG)-force relations observed in the first dorsal interosseous (FDI) muscle of hemiparetic stroke survivors.
  
  
  METHODS
  Fourteen stroke subjects were instructed to perform different levels of index finger abduction using their paretic and contralateral hands, respectively. Surface EMG and force signals were recorded from the FDI muscle. The EMG-force relation was constructed using linear regression of the EMG amplitude and force measurements.
  
  
  RESULTS
  We found that there were diverse changes in the slope of the EMG-force relations in paretic muscles compared with contralateral muscles, with significant increases and decreases being observed relative to the contralateral side. Regression analysis did not verify strong correlations between the ratio of paretic and contralateral muscle EMG-force slopes and any clinical parameters.
  
  
  CONCLUSIONS
  These findings suggest that there appear to be different types of processes (eg, motor unit control property changes, muscle fiber atrophy, spinal motoneuron degeneration, muscle fiber reinnervation, etc) at work post stroke that may impact the EMG-force relations and that may be present in varying degree in any given stroke survivor.
authors.affiliation: Institute of Biomedical Engineering, University of Science and Technology of China, Hefei, China Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, Illinois, USA Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, Illinois, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhou
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Li
authors.forename: William Zev
authors.initials: WZ
authors.lastname: Rymer
mesh_terms: D000368:Aged; D004576:Electromyography; D005260:Female; D007839:Functional Laterality; D006225:Hand; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D020521:Stroke / Q000473:pathology* / Q000503:physiopathology
keywords: EMG-force relation; FDI muscle; hemiparetic stroke