INVESTIGATING THE EXISTENCE OF INTERLIMB MECHANICAL VARIABILITY IN THE PERFORMANCE OF THE CUTTING MANOUVERE AND ASSOCIATED INJURY POTENTIAL.

Abstract

The consensus in current research suggests that variability within the mechanics of movement is a healthy, not injurious, trait, as it may provide protection to athletes by distributing stresses within the body. There is still limited research that has investigated variability in dynamic movements such as cutting where variability may be even more beneficial to the athlete. Similarly there is an apparent neglect within current research to gain an understanding of the role dominance may play in injury potential of an athlete, specifically at the knee which is regularly loaded when a cutting manoeuvre is preformed and is linked to the failure of the Anterior Cruciate Ligament (ACL). With the suggestion that dominance indicates an over-reliance on one limb this study aimed to examine the existence of variability with the mechanics of the knee joint on both the non-dominant and dominant cutting limb to provide a greater insight into injury potential. Two female athletes, injury free and with vast experience of the cutting manoeuvre were chosen it participant in this study. Participants performed two trial sessions separated by 10 days. Each session consisted of 20 unanticipated cutting manoeuvres (n=10 on both limbs) during which kinematic data of six assigned rotational degrees of freedom (abduction/adduction; flexion and extension; internal rotation and external rotation) and kinetic data were collected using an automated analysis system (CODA motion) and Kistler force plate respectively. Assessment of inter and intra limb variability was performed using percentage route mean squared difference for continuous data and Co-efficient of variation for discrete data. The result showed that the inter-limb mechanical variability was lower in the non-dominant limb for the majority of trials, significantly in abduction and adduction in the frontal plane (p=0.02, 0.03,0.02) however, the non-dominant limb was subject to lower levels of loading, consistent with greater flexion angles. Furthermore in the frontal plane there was evidence of a dual abduction peak where, just prior to mid stance (50% Movement time), the limb underwent a period of adduction. The results from this study indicate that there are differing levels of variability evident within dominant and non-dominant limbs; it is therefore tentatively suggested that variability is of benefit to an athlete and that they may be at greater risk of injury if significant dominance is present in performance.