LE3 .A278 2020

2020

Landry, Scott

Acadia University

Bachelor of Kinesiology

Honours

Kinesiology

Kinesiology

The anterior cruciate ligament (ACL) is a primary stabilizer of the human knee. Injuries to this ligament are typically the result of decelerating movements such as sudden change in direction or landing from a jump. Injury to this ligament is common among athletes, especially those competing in multidirectional, team sports. Rupture to the ACL typically results in costly surgical reconstruction and a lengthy rehabilitation. Additionally, athletes who sustain ACL injuries are at an increased risk for reinjury and premature osteoarthritis development. Roughly 70% of ACL injuries occur from non-contact mechanisms and female athletes are at a 2 to 8 times greater risk of injury than their male athlete counterparts post puberty. Biomechanical differences are known to exist between athletes of various sport backgrounds, however, to date there are no studies that have examined biomechanical differences across groups of athletes from different sport backgrounds. The purpose of this study was two-fold. Firstly, this study aimed to determine whether athletes from different sport backgrounds (field or court) have altered biomechanics when performing both the single and double leg drop jump tasks. Secondly, this study aimed to identify biomechanical differences of the lower extremity between male and female athletes during the drop jump tasks. The hypotheses for the current study were: a) field and court sport athletes would not differ biomechanically; b)female athletes would demonstrate lower levels of hip and knee flexion, as well as increased knee abduction angles compared to male athletes; c)female athletes would have greater knee extension moments during landing; d) female athletes would demonstrate greater frontal plane knee excursions compared to males. A total of 98 athletes aged 12-28 who were involved in cutting and jumping sports participated in the current study. Participants were divided into four groups based on sex and sport background (field or court): field female (n=27, age=18.0±2.7 years); court female (n=29, age=17.9±3.0 years); field male (n=27, age=18.0± 3.0 years); court male (n=15, age=18. 1±4.3 years). A 12-camera motion capture system and three force plates were used to capture joint angles and moments of the hip and knee as well as frontal plane knee excursion distance during both a double and single leg drop jump protocol. Two-way ANOVAs (p<0.05) were performed on joint angles, moments and frontal plane knee excursion to test for a sex (male vs. female), sport (field vs. court), or interaction effect. Bonferroni corrected pairwise comparisons were performed if any interaction effects were found. Results showed that male athletes exhibited greater internal knee extension moments than their female counterparts during both single and double leg drop jumps. No significant differences were observed for either flexion or adduction angles of the hip and knee based on sex. Additionally, field sport athletes demonstrated increased hip and knee flexion angles during both the single and double leg landing task. Court sport athletes demonstrated greater knee frontal plane excursion than their field sport counterparts. These differences suggest that sport background influences biomechanics during single and double leg drop jump tasks which could potentially affect ACL injury risk of these groups. The results of this study expanded on the knowledge regarding biomechanical differences between male and female athletes that could predispose females to ACL injury. Furthermore, previously unknown kinematic differences in drop jump landing strategies between field and court sport athletes were identified.

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https://scholar.acadiau.ca/islandora/object/theses:3431