title: Neuromuscular dysfunction in diabetes:  role of nerve impairment and training status.
abstract: OBJECTIVE
  The purpose of this study was to investigate the effect of diabetes, motor nerve impairment, and training status on neuromuscular function by concurrent assessment of the torque-velocity relationship and muscle fiber conduction velocity (MFCV).
  
  
  METHODS
  Four groups were studied (n = 12 each): sedentary patients with diabetes in the first (lower) and fourth (higher) quartile of motor nerve conduction velocity (D1 and D4, respectively), trained diabetic (TD) patients, and nondiabetic sedentary control (C) subjects. Maximal isometric and isokinetic contractions were assessed over a wide range of angular velocities for the elbow flexors and knee extensors to evaluate the torque-velocity relationship. Simultaneously, MFCV was estimated from surface electromyography of the vastus lateralis and biceps brachii.
  
  
  RESULTS
  Isometric strength was similar among groups. The dynamic strength of elbow flexors was reduced in patients with diabetes at the higher contraction speeds. The strength of knee extensors was lower in sedentary patients with diabetes at all velocities considered, with significantly lower values in D1 than that in D4 at 60°, 90°, and 120°·s(-1), whereas it was similar between TD and C subjects, especially at low contraction velocities. At the vastus lateralis, but not the biceps brachii, MFCV was lower in D1 and D4 as compared with TD and C subjects, showing similar values.
  
  
  CONCLUSIONS
  Muscle weakness in diabetes affects also the upper limb, although to a lower extent than the lower limb, is only partly related to motor nerve impairment, and is dependent on contraction velocity. Exercise training might counteract diabetes-induced alterations in muscle fiber contractile properties and MFCV.
authors: Department of Human Movement and Sport Sciences, Foro Italico University, Rome, Italy. massimo.sacchetti@uniroma4.it
authors: Massimo
authors: M
authors: Sacchetti
authors: Massimo
authors: M
authors: Scotto Sacchetti
authors: Stefano
authors: S
authors: Balducci
authors: Ilenia
authors: I
authors: Bazzucchi
authors: Flaminia
authors: F
authors: Carlucci
authors: Alessandro
authors: A
authors: Scotto di Palumbo
authors: Alessandro Scotto
authors: AS
authors: Di Palumbo
authors: Jonida
authors: J
authors: Haxhi
authors: Francesco
authors: F
authors: Conti
authors: Nicolina
authors: N
authors: Di Biase
authors: Eugenio
authors: E
authors: Calandriello
authors: Giuseppe
authors: G
authors: Pugliese
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D003922:Diabetes Mellitus, Type 1 / Q000150:complications* / Q000628:therapy; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000628:therapy; D003929:Diabetic Neuropathies / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D004576:Electromyography; D005081:Exercise Therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology; D009431:Neural Conduction / Q000502:physiology*; D016037:Single-Blind Method; D019415:Torque