Évaluation de l'impact combiné d'une tâche perceptivo-cognitive et de la fatigue musculaire sur la biomécanique du membre inférieur lors d'atterrissages

Abstract

Lower limbs are victims of many injuries at the hip, knee or ankle during sports. One of the main injuries is the anterior cruciate ligament injury (ACL). The majority of these occur without player or environment contact, following a movement such as a landing or change of direction. Much attention has been focused on muscle strengthening to delay the biomechanical effects of muscle fatigue in order to reduce the risk of injury. Nevertheless, the number of ACL injuries is still high. Recent studies were focused on another cause of injury, and they indicated there might be a link between cognitive factors and ACL injuries. In our study, we want to demonstrate that there is a link between biomechanical degradation and cognitive load. In order to do it, kinematic data were acquired from nineteen athlètes who performed jumping and landing trials. Half of the trials were performed while tracking multiple virtual objects in a 3D volume, meant to simulate a game-situation cognitive load. Fatigue caused significant decrease in knee flexion at peak stance (PS), significant increase in PS knee abduction and PS internal rotation. In contrast, no significant changes were noted concerning the pre-fatigue MOT effect. However, an eight participants group increased their PS knee abduction when the MOT effect was combine with fatigue. Knowing that abduction is a factor contributing to increase strain on the ACL, we may suppose that the risk of injury increases during single leg landing. Further studies are needed to more understand the role of the cognitive impact on biomechanics of the lower limbs and to find a way to identify people with a higher risk of injury. Trainings of MOT, which lead to improvements, added to neuromuscular trainings may be necessary to counter changes which increase the risk of injuries.

Date	19 Nov 2015
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	David Labbé (Supervisor) & Jocelyn Faubert (Co-supervisor)