title: The effects of superimposed electrical stimulation of the quadriceps muscles on performance in different motor tasks.
abstract: BACKGROUND
  Some examples are presented to show how superimposed electrical stimulation of muscles during maximum voluntary effort can be used to enable subjects to achieve greater joint torque, rate of joint torque development, and the joint angular velocity as when performing only voluntarily with maximum effort.
  
  
  METHODS
  
  
  
  METHODS
  Ten students of physical education not involved into a regular sport training participated the study.
  
  
  METHODS
  The subjects performed isometric and concentric knee extensions and squat jumps, without and with superimposed electrical stimulation of the quadriceps muscles.
  
  
  METHODS
  A knee torque and angular displacement were observed during isometric and concentric knee extension. During the jumping, a vertical component of the ground reaction force was measured.
  
  
  RESULTS
  Results showed that the maximal knee torque, as well as a torque rise, were higher in isometric knee extension trials with superimposed electrical stimulation. The same was observed in concentric knee extensions, where greater knee torque during superimposed electrical stimulation also resulted in higher angular velocity and a more extended knee at the end of the movement. In squat jumps, the application of the superimposed electrical stimulation resulted in poorer performance.
  
  
  CONCLUSIONS
  It was concluded that superimposed electrical stimulation was effective in some simple motor tasks, but not in more complex tasks where a co-ordination of multiple muscles of different groups was necessary for improved performance.
authors.affiliation: Faculty of Sport, University of Ljubljana, Slovenia.
authors.forename: V
authors.initials: V
authors.lastname: Strojnik
mesh_terms: D000054:Acceleration; D000328:Adult; D004558:Electric Stimulation / Q000295:instrumentation / Q000379:methods; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009048:Motor Skills / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D019415:Torque; D016474:Weight-Bearing / Q000502:physiology