title: Later stages of diabetic neuropathy affect the complexity of the neuromuscular system at the knee during low-level isometric contractions.
abstract: BACKGROUND
  This study evaluates the complexity of force and surface electromyography (sEMG) during knee extension and flexion at low-level isometric contractions in individuals with different degrees of diabetic peripheral neuropathy (DPN).
  
  
  METHODS
  Ten control and 38 diabetic participants performed isometric contractions at 10%, 20%, and 30% of maximal voluntary contraction. Knee force and multichannel sEMG from vastus lateralis (VL) and biceps femoris were acquired. The SD of force and sample entropy (SaEn) of both force and sEMG were computed.
  
  
  RESULTS
  Participants with moderate DPN demonstrated high force-SD and low force-SaEn. Severely affected participants showed low SaEn in VL at all force levels.
  
  
  CONCLUSIONS
  DPN affects the complexity of the neuromuscular system at the knee for the extension task during low-level isometric contractions, with participants in the later stages of the disease (moderate and severe) demonstrating most of the changes. Muscle Nerve 57: 112-121, 2018.
authors.affiliation: Laboratory of Biomechanics of Human Movement, Department of Physical Therapy, Speech and Occupational Therapy, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Eneida Y
authors.initials: EY
authors.lastname: Suda
authors.affiliation: Laboratory of Biomechanics of Human Movement, Department of Physical Therapy, Speech and Occupational Therapy, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Isabel C N
authors.initials: ICN
authors.lastname: Sacco
authors.affiliation: SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Fredrik Bajers Vej 7 D-3, 9220, Aalborg East, Denmark.
authors.forename: Rogerio P
authors.initials: RP
authors.lastname: Hirata
authors.affiliation: SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Fredrik Bajers Vej 7 D-3, 9220, Aalborg East, Denmark.
authors.forename: Afshin
authors.initials: A
authors.lastname: Samani
authors.affiliation: Laboratory of Biomechanics of Human Movement, Department of Physical Therapy, Speech and Occupational Therapy, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Thiago T
authors.initials: TT
authors.lastname: Kawamura
authors.affiliation: SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Fredrik Bajers Vej 7 D-3, 9220, Aalborg East, Denmark.
authors.forename: Pascal
authors.identifier: http://orcid.org/0000-0002-2164-234X
authors.initials: P
authors.lastname: Madeleine
mesh_terms: D000328:Adult; D000368:Aged; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D007717:Knee / Q000294:innervation / Q000503:physiopathology*; D007719:Knee Joint / Q000294:innervation / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000294:innervation / Q000503:physiopathology
keywords: complexity; diabetes mellitus; force; high-density EMG; motor variability; sample entropy; surface electromyography