title: Effects of involuntary eccentric contraction training by neuromuscular electrical stimulation on the enhancement of muscle strength.
abstract: BACKGROUND
  Neuromuscular electrical stimulation is well-known as a modality to improve the performance of neuromuscular system, but its clinical value on muscle strengthening remains equivocal. In this study, we designed a system for an involuntary eccentric contraction of biceps brachii muscles using continuous passive movement and commercial neuromuscular electrical stimulation devices.
  
  
  METHODS
  To investigate the effects of involuntary eccentric contraction training by neuromuscular electrical stimulation on the enhancement of muscle strength, seven healthy men between the ages of 24 and 29 years participated in this study. Participants were trained two times per week for 12 weeks. Each exercise session was performed for 30 min with no rest intervals. Isometric elbow flexion torque and biceps brachii muscle thickness were chosen as evaluation indices, and were measured at pre-/post-training.
  
  
  RESULTS
  After the 12-week training, the isometric elbow flexion torque of the trained side significantly increased by approximately 23% compared to the initial performance (P<0.01). Meanwhile, the torque of the untrained side showed no significant change (P=0.862). During the 12-week training period, the biceps brachii muscle thickness of the trained side significantly increased by around 8% at rest and 16% at maximum voluntary contraction (P<0.01).
  
  
  CONCLUSIONS
  The developed system and the technique show promising results, suggesting that it has the potential to be used to increase the muscle strength in patients with neuromuscular disease and to be implemented in design rehabilitative protocols.
authors.affiliation: Department of Biomedical Engineering and Institute for Convergence Study of Bio-Medical Wellness, Yonsei University, Maeji-ri, Heungeop-myeon, Wonju-si, Gangwon-do 220-710, Republic of Korea.
authors.forename: Jongsang
authors.initials: J
authors.lastname: Son
authors.affiliation: Department of Biomedical Engineering and Institute for Convergence Study of Bio-Medical Wellness, Yonsei University, Maeji-ri, Heungeop-myeon, Wonju-si, Gangwon-do 220-710, Republic of Korea.
authors.forename: Dongyeop
authors.initials: D
authors.lastname: Lee
authors.affiliation: Department of Biomedical Engineering and Institute for Convergence Study of Bio-Medical Wellness, Yonsei University, Maeji-ri, Heungeop-myeon, Wonju-si, Gangwon-do 220-710, Republic of Korea. Electronic address: younghokim@yonsei.ac.kr.
authors.forename: Youngho
authors.initials: Y
authors.lastname: Kim
mesh_terms: D000328:Adult; D001132:Arm; D001835:Body Weight; D004551:Elbow Joint / Q000502:physiology; D004558:Electric Stimulation; D004867:Equipment Design; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D012046:Rehabilitation; D012189:Retrospective Studies; D012984:Software; D019415:Torque; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods
keywords: Electromyostimulation; Rehabilitation; Strength training