title: Can the efficacy of electrically stimulated pedaling using a commercially available ergometer BE improved by minimizing the muscle stress-time integral?
abstract: BACKGROUND
  The cardiorespiratory and muscular strength benefits of functional electrical stimulation (FES) pedaling for spinal cord injury (SCI) subjects are limited because the endurance of electrically stimulated muscle is low.
  
  
  METHODS
  We tested new electrical stimulation timing patterns (Stim3, designed using a forward dynamic simulation to minimize the muscle stress-time integral) to determine whether SCI subjects could increase work and metabolic responses when pedaling a commercial FES ergometer. Work, rate of oxygen uptake (VO(2)), and blood lactate data were taken from 11 subjects (injury level T4-T12) on repeated trials.
  
  
  RESULTS
  Subjects performed 11% more work pedaling with Stim3 than with existing stimulation patterns (StimErg) (P = 0.043). Average (VO(2)) and blood lactate concentrations were not significantly different between Stim3 (442 ml/min, 5.9 mmol/L) and StimErg (417 ml/min, 5.9 mmol/L).
  
  
  CONCLUSIONS
  The increased mechanical work performed with Stim3 supports the use of patterns that minimize the muscle stress-time integral to prolong FES pedaling.
authors.affiliation: Mechanical Engineering Department, University of Delaware, 126 Spencer Laboratory, Newark, Delaware 19711, USA. nilsh@udel.edu
authors.forename: Nils A
authors.initials: NA
authors.lastname: Hakansson
authors.forename: Maury L
authors.initials: ML
authors.lastname: Hull
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001642:Bicycling / Q000502:physiology*; D004599:Electric Stimulation Therapy; D016552:Ergometry; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010101:Oxygen Consumption; D013119:Spinal Cord Injuries / Q000097:blood / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D055815:Young Adult
chemical_list: D019344:Lactic Acid