title: Fatigue reduction during aggregated and distributed sequential stimulation.
abstract: Transcutaneous neuromuscular electrical stimulation (NMES) can generate muscle contractions for rehabilitation and exercise. However, NMES-evoked contractions are limited by fatigue when they are delivered "conventionally" (CONV) using a single active electrode. Researchers have developed "sequential" (SEQ) stimulation, involving rotation of pulses between multiple "aggregated" (AGGR-SEQ) or "distributed" (DISTR-SEQ) active electrodes, to reduce fatigue (torque-decline) by reducing motor unit discharge rates. The primary objective was to compare fatigue-related outcomes, "potentiation," "variability," and "efficiency" between CONV, AGGR-SEQ, and DISTR-SEQ stimulation of knee extensors in healthy participants.
  
  
  
  Torque and current were recorded during testing with fatiguing trains using each NMES type under isometric and isokinetic (180°/s) conditions.
  
  
  
  Compared with CONV stimulation, SEQ techniques reduced fatigue-related outcomes, increased potentiation, did not affect variability, and reduced efficiency.
  
  
  
  SEQ techniques hold promise for reducing fatigue during NMES-based rehabilitation and exercise; however, optimization is required to improve efficiency. Muscle Nerve 56: 271-281, 2017.
authors.affiliation: Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada.
authors.forename: Austin J
authors.initials: AJ
authors.lastname: Bergquist
authors.affiliation: Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada.|Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Vishvek
authors.initials: V
authors.lastname: Babbar
authors.affiliation: Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada.|Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Saima
authors.initials: S
authors.lastname: Ali
authors.affiliation: Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada.|Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Milos R
authors.initials: MR
authors.lastname: Popovic
authors.affiliation: Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada.|Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Kei
authors.initials: K
authors.lastname: Masani
mesh_terms: D000328:Adult; D001703:Biophysics; D004566:Electrodes; D004576:Electromyography; D005221:Fatigue / Q000503:physiopathology* / Q000534:rehabilitation*; D005260:Female; D006801:Humans; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D019415:Torque; D004561:Transcutaneous Electric Nerve Stimulation; D055815:Young Adult
keywords: asynchronous; distributed; electrical stimulation; fatigue; functional electrical stimulation; potentiation; quadriceps; sequential; synchronous