Motor learning in ACL injury prevention

The physical and psychosocial consequences of an anterior cruciate ligament (ACL) injury are large, for example limitations in daily life, reduction of sports participation, development of osteoarthritis in the knee and increased risk for re-rupture. The importance of prevention is clear, however we have not been able yet to reduce the ACL injury incidence. The aim of this dissertation was therefore to examine how current ACL injury prevention protocols can be optimized through enhanced motor learning. Motor skills can be learned with attention directed to the movement itself (e.g. “flex your knees”), which is defined as an internal focus. Whereas with an external focus, attention is directed towards the effect of the movement (e.g. “imagine you are going to sit on a chair”). In the current ACL injury prevention programs athletes are mostly encouraged to focus on the quality of their movements in order to improve awareness and knee control during cutting, jumping and landing. However, telling athletes explicitly how to move may be counterproductive and less suitable for the acquisition of the control required for complex motor skills. This dissertation shows that providing athletes with individual feedback with an external focus component and video feedback seems promising when learning movement patterns: safer landing techniques were used. A focus on the movement effect (i.e. external focus) probably promotes the utilization of unconscious or automatic processes. This enhances the transfer to the field and retention of learned movement patterns over time. Finally, performance remained optimal (i.e. running speed and jump height). When training staff realize that injury prevention (enhanced movement technique) and performance enhancement go hand in hand, injury prevention can be viewed as ’part of the game’.