title: The impact of type 1 diabetes and diabetic polyneuropathy on muscle strength and fatigability.
abstract: OBJECTIVE
  Although it is widely accepted that diabetic polyneuropathy (DPN) is linked to a marked decline in neuromuscular performance, information on the possible impact of type 1 diabetes (T1D) on muscle strength and fatigue remains unclear. The purpose of this study was to investigate the effects of T1D and DPN on strength and fatigability in knee extensor muscles.
  
  
  METHODS
  Thirty-one T1D patients (T1D), 22 T1D patients with DPN (DPN) and 23 matched healthy control participants (C) were enrolled. Maximal voluntary contraction (MVC) and endurance time at an intensity level of 50% of the MVC were assessed at the knee extensor muscles with an isometric dynamometer. Clinical characteristics of diabetic patients were assessed by considering a wide range of vascular and neurological parameters.
  
  
  RESULTS
  DPN group had lower knee extensor muscles strength than T1D (-19%) and the C group (-37.5%). T1D group was 22% weaker when compared to the C group. Lower body muscle fatigability of DPN group was 22 and 45.5% higher than T1D and C group, respectively. T1D group possessed a higher fatigability (29.4%) compared to C group. A correlation was found between motor and sensory nerve conduction velocity and muscle strength and fatigability.
  
  
  CONCLUSIONS
  Patients with T1D are characterised by both a higher fatigability and a lower muscle strength, which are aggravated by DPN. Our data suggest that factors other than nervous damage play a role in the pathogenesis of such defect.
authors.affiliation: Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro De Bosis, 15, 00135, Rome, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Orlando
authors.affiliation: Department of Clinical and Molecular Medicine, "La Sapienza" University, Rome, Italy.|Diabetes Unit, Sant'Andrea Hospital, Rome, Italy.|Metabolic Fitness Association, Monterotondo, Rome, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Balducci
authors.affiliation: Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro De Bosis, 15, 00135, Rome, Italy.
authors.forename: Ilenia
authors.initials: I
authors.lastname: Bazzucchi
authors.affiliation: Department of Clinical and Molecular Medicine, "La Sapienza" University, Rome, Italy.|Diabetes Unit, Sant'Andrea Hospital, Rome, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pugliese
authors.affiliation: Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro De Bosis, 15, 00135, Rome, Italy. massimo.sacchetti@uniroma4.it.
authors.forename: Massimo
authors.identifier: http://orcid.org/0000-0002-1332-2215
authors.initials: M
authors.lastname: Sacchetti
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003922:Diabetes Mellitus, Type 1 / Q000150:complications* / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000473:pathology; D012189:Retrospective Studies
keywords: Diabetic polyneuropathy; Muscle fatigue; Muscle strength; Type 1 diabetes