title: Joint-position sense is altered by football pre-participation warm-up exercise and match induced fatigue.
abstract: BACKGROUND
  The demands to which football players are exposed during the match may augment the risk of injury by decreasing the sense of joint position. This study aimed to assess the effect of pre-participation warm-up and fatigue induced by an official football match on the knee-joint-position sense of football players.
  
  
  METHODS
  Fourteen semi-professional male football players (mean age: 25.9±4.6 years old) volunteered in this study. The main outcome measures were rate of perceived exertion and knee-joint-position sense assessed at rest, immediately after a standard warm-up (duration 25 min), and immediately after a competitive football match (90 minutes duration).
  
  
  RESULTS
  Perceived exertion increased significantly from rest to the other assessments (rest: 8.6±2.0; after warm-up: 12.1±2.1; after football match: 18.5±1.3; p<0.001). Compared to rest, absolute angular error decreased significantly after the warm-up (4.1°±2.2° vs. 2.0°±1.0°; p=0.0045). After the match, absolute angular error (8.7°±3.8°) increased significantly comparatively to both rest (p=0.001) and the end of warm-up (p<0.001). Relative error showed directional bias with an underestimation of the target position, which was higher after the football match compared to both rest (p<0.001) and after warm-up (p<0.001).
  
  
  CONCLUSIONS
  The results indicate that knee-joint-position sense acuity was increased by pre-participation warm-up exercise and was decreased by football match-induced fatigue.
  
  
  CONCLUSIONS
  Warm-up exercises could contribute to knee injury prevention, whereas the deleterious effect of match-induced fatigue on the sensorimotor system could ultimately contribute to knee instability and injury.
authors: University of Porto, Faculty of Sport, Research Centre in Physical Activity, Health and Leisure (CIAFEL), Porto, Portugal.
authors: Eduardo
authors: E
authors: Salgado
authors: School of Health Sciences, University of Aveiro, Aveiro, Portugal.
authors: Fernando
authors: F
authors: Ribeiro
authors: University of Porto, Faculty of Sport, Research Centre in Physical Activity, Health and Leisure (CIAFEL), Porto, Portugal. Electronic address: joliveira@fade.up.pt.
authors: José
authors: J
authors: Oliveira
mesh_terms: D000328:Adult; D005538:Football / Q000502:physiology*; D006801:Humans; D007718:Knee Injuries / Q000517:prevention & control*; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D011434:Proprioception; D016059:Range of Motion, Articular; D063996:Warm-Up Exercise / Q000502:physiology*
keywords: Fatigue; Football; Proprioception; Warm-up