title: Effects of eccentric exercise on trapezius electromyography during computer work with active and passive pauses.
abstract: BACKGROUND
  The aim of this laboratory study was to investigate the effects of eccentric exercises on the trapezius muscle spatial electromyographic (EMG) activity during computer work with active and passive pauses.
  
  
  METHODS
  Twelve healthy male subjects performed computer work with passive (relax) and active (30% maximum voluntary contraction of shoulder elevation) pauses given every 40s over 2 days, before, immediately and 24h after eccentric exercise. Surface EMG signals were recorded from four parts of the trapezius during computer work.
  
  
  RESULTS
  EMG amplitude during computer work decreased immediately after exercise (P<0.05). In the clavicular and descending parts of the trapezius, the centroid of exposure variation analysis along the time axis was lower during computer work with active pauses compared with passive ones (P<0.05). Further, lower values of relative rest time was observed during active pause (P<0.05).
  
  
  CONCLUSIONS
  Eccentric exercises had a short term effect on muscle activation pattern during computer work, and decreased the muscle activity immediately after the exercises. The results of this study showed a more variable trapezius activity pattern and a lower trapezius rest with active pauses compared with passive pauses. Moreover, eccentric exercises resulted in a less variable activation pattern, decreasing the effect of active pauses.
authors.affiliation: Laboratory for Ergonomics and Work-related Disorders, Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7 D-3, 9220 Aalborg East, Denmark.
authors.forename: Afshin
authors.initials: A
authors.lastname: Samani
authors.forename: Andreas
authors.initials: A
authors.lastname: Holtermann
authors.forename: Karen
authors.initials: K
authors.lastname: Søgaard
authors.forename: Pascal
authors.initials: P
authors.lastname: Madeleine
mesh_terms: D004576:Electromyography / Q000379:methods*; D005080:Exercise Test; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D012146:Rest / Q000502:physiology; D012782:Shoulder / Q000502:physiology*; D015443:Word Processing; D055815:Young Adult