title: The effect of fatigue on knee position sense is not dependent upon the muscle group fatigued.
abstract: BACKGROUND
  Muscle fatigue could have a greater impact on position sense when antagonists of the movement are fatigued. Hence, this study aimed to compare the effects of antagonist and agonist exercise-induced muscle fatigue on knee joint position sense.
  
  
  METHODS
  This within-subjects repeated-measures study included 40 subjects. Knee position sense and muscle strength were measured before and after two exercise protocols consisting of 30 consecutive maximal concentric/eccentric contractions of the knee extensors or flexors on the isokinetic dynamometer at an angular velocity of 180°/s (3.14 rad/s).
  
  
  RESULTS
  Both exercise protocols increased the absolute angular error (F(1.78) = 39.89, P < 0.001; knee extensors protocol from 2.0 ± 1.3° to 3.5 ± 2.0°, knee flexors protocol from 2.1 ± 1.2° to 3.7 ± 2.2°), and no differences were detected between protocols (F(1.78) = 0.034, P = 0.855). No changes were observed in the relative angular error.
  
  
  CONCLUSIONS
  Muscle fatigue affects knee position sense, and the deleterious effect is not different depending upon the muscle group fatigued.
authors.affiliation: Department of Physiotherapy, Polytechnic Health Institute of the North, R. Central de Gandra, Gandra, Portugal. fernando.silva.ribeiro@gmail.com
authors.forename: Fernando
authors.initials: F
authors.lastname: Ribeiro
authors.forename: João
authors.initials: J
authors.lastname: Venâncio
authors.forename: Pedro
authors.initials: P
authors.lastname: Quintas
authors.forename: José
authors.initials: J
authors.lastname: Oliveira
mesh_terms: D000293:Adolescent; D000328:Adult; D015444:Exercise / Q000502:physiology; D006801:Humans; D007717:Knee / Q000502:physiology*; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D011434:Proprioception / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology*