Age and Knee Confidence Effects on LESS and LESS-RMC Scores in Female Youth Soccer Players

Abstract

INTRODUCTION: Anterior Crucial Ligament (ACL) injuries are common in female soccer players and can have serious, even lifelong consequences. The Landing Error Scoring System (LESS) and a modification of the LESS, the LESS-RMC, have been useful tools in screening athletes and identifying individuals at “high-risk” so appropriate interventions could be provided. However, it is unclear how knee confidence and age influences these screening tools in female soccer athletes. PURPOSE: The aim of this study was to investigate the effects of age and knee confidence on ACL injury risk classification in female youth soccer players. METHODS: 178 healthy female youth soccer players (ht: 1.63±0.07m, mass: 48.8±4.9kg, age: 14.1±1.5yrs) participated in this study. Participants were asked to jump from a 30cm box a distance 50% of their height where they immediately performed a maximum vertical jump and landing upon initial ground contact. Two HD cameras were used to record (60 Hz) this motion in the frontal and sagittal planes. The video of the task was then used to assess the participant’s ACL injury risk by evaluating these landings using the LESS and LESS-RMC procedures. Knee confidence was evaluated by using a 5-point Likert scale in response to an item asking “How much do you trust your knee” from the knee-related quality of life subscale in the KOOS knee questionnaire. The participants were classified as confident if they answered “completely” and not confident for all other responses. Two-way ANOVAs were used to investigate the effects of age group (11-12, 13-14, 15-16 and 17-18 y) and knee confidence on the LESS and LESS-RMC scores. RESULTS: There was a statistically significant main effect of age on the LESS score, [F (3, 167) = 2.667, p = 0.049.]. Post-hoc tests revealed that the age group of 11-12 years displayed significantly higher LESS scores (6.43±2.14) than the 17-18 group (4.49±2.11) (p = 0.029). There was no significant main effect for knee confidence (p = 0.501). CONCLUSION: The results reveal that female soccer players in the 11-12 age range are at a greater risk of ACL injury than the 17-18 age range. Further research should be conducted to examine the mechanical contribution to this risk and methods to reduce injury risk across age ranges.