title: Joint torque variability and repeatability during cyclic flexion-extension of the elbow.
abstract: BACKGROUND
  Joint torques are generally of primary importance for clinicians to analyze the effect of a surgery and to obtain an indicator of functional capability to perform a motion. Given the current need to standardize the functional evaluation of the upper limb, the aim of this paper is to assess (1) the variability of the calculated maximal elbow joint torque during cyclic elbow flexion-extension movements and (2) participant test-retest repeatability in healthy young adults. Calculations were based on an existing non-invasive method including kinematic identification and inverse dynamics processes.
  
  
  METHODS
  Twelve healthy young adults (male n = 6) performed 10 elbow flexion-extension movement carrying five different dumbbells (0, 1, 2, 3 and 4 kg) with several flexion-extension frequencies (½, (1)/3, ¼ Hz) to evaluate peak elbow joint torques.
  
  
  RESULTS
  Whatever the condition, the variability coefficient of trial peak torques remained under 4 %. Bland and Altman plot also showed good test-retest, whatever the frequency conditions for the 0, 1, 2, and 3 kg conditions.
  
  
  CONCLUSIONS
  The good repeatability of the flexion-extension peak torques represents a key step to standardize the functional evaluation of the upper limb.
authors.affiliation: Department of kinanthropology, Université du Québec à Montréal, Montreal, Qc Canada ; Research & Engineering Chair Applied to Pediatrics (RECAP), Marie Enfant Rehabilitation Centre (CRME) - Research Center - Sainte-Justine UHC, and École Polytechnique de Montréal, Montreal, Qc Canada.
authors.forename: Laurent
authors.initials: L
authors.lastname: Ballaz
authors.affiliation: Department of mechanical engineering, École Polytechnique de Montréal, Montreal, Qc Canada ; Research & Engineering Chair Applied to Pediatrics (RECAP), Marie Enfant Rehabilitation Centre (CRME) - Research Center - Sainte-Justine UHC, and École Polytechnique de Montréal, Montreal, Qc Canada ; CRME - Research Center, Office GR-123, 5200, East Bélanger Street, H1T 1C9 Montréal, QC Canada.
authors.forename: Maxime
authors.initials: M
authors.lastname: Raison
authors.affiliation: Institute of NeuroSciences (IoNS), Université catholique de Louvain, Bruxelles, Belgium.
authors.forename: Christine
authors.initials: C
authors.lastname: Detrembleur
authors.affiliation: Department of mechanical engineering, École Polytechnique de Montréal, Montreal, Qc Canada ; Research & Engineering Chair Applied to Pediatrics (RECAP), Marie Enfant Rehabilitation Centre (CRME) - Research Center - Sainte-Justine UHC, and École Polytechnique de Montréal, Montreal, Qc Canada.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Gaudet
authors.affiliation: Department of kinanthropology, Université du Québec à Montréal, Montreal, Qc Canada ; Research & Engineering Chair Applied to Pediatrics (RECAP), Marie Enfant Rehabilitation Centre (CRME) - Research Center - Sainte-Justine UHC, and École Polytechnique de Montréal, Montreal, Qc Canada.
authors.forename: Martin
authors.initials: M
authors.lastname: Lemay
keywords: Elbow joint torques; Inverse dynamics; Kinematic solidification; Modeling; Repeatability; Variability