LE3 .A278 2020

2020

Lattimer, Lauren

Acadia University

Bachelor of Kinesiology

Honours

Kinesiology

Kinesiology

Concussions are an inevitable risk posed to all athletes, especially those within contact sports. A concussion is the result of linear and angular kinematics of the brain tissue caused by direct and indirect head contact. Female athletes participating in contact sports demonstrate a concussion injury risk factor that is two times greater than their skill and age-matched male counterparts. Rugby is one of such contact sports in which tackles comprise the main mechanism for concussion; which is caused by inertial impacts, rather than direct impact to the head. In numerous sports, female athletes exhibit higher measurements of acceleration and therefore higher concussion risk. Recent literature has outlined the importance of neck muscle strength and neuromuscular characteristics in the mitigation of excessive head kinematics resulting in such brain injuries. In theory, those who display greater strength and anticipatory activation of the cervical musculature will decrease the amount of head acceleration experienced, and lower concussion risk substantially. The current study investigated the effect of sex on musculoskeletal and neuromuscular characteristics of the cervical musculature, as well as head kinematics during a simulated landing-portion of a rugby tackle. Twenty-three (females n = 15, males n=8) university-aged rugby athletes participated in an unanticipated perturbation simulation; and a series of clinical tests of the cervical musculature. Anthropometrics of the head and neck, including neck girth, head girth, head-neck segment length and mass,were ob tained. Maximal isometric neck strength was measured in kilograms of force (kgf) in all planes of motion, using handheld dynamometry. Endurance of the neck musculature was determined using the Isometric Endurance test. Electromyography and accelerometers were used to analyze activity of the sternocleid omastoid, upper trapezius, external and internal oblique muscles; as well as to quantify head, neck, and trunk change in velocity during a simulated unexpected dynamic task. One-way MANOVAs were used to determine sex differences in anthropometrics, muscle activation, and head kinematics. Independent t-tests were used to compare neck muscle endurance. The results of this study found that males demonstrated significantly greater neck girth, head girth, and head-neck segment mass. Isometric strength was significantly different with exception of the left upper trapezius; with males demonstrating 40-60% greater strength. Males demonstrated 43% greater muscle endurance than females. No statistical significance in neuromuscular activation was found between sexes; however, female participants exhibited a muscle activation strategy of bilateral co-contraction of the sternocleidomastoid, while males utilized contralateral muscles to the diving direction in order to stabilize the head. Males had statistically significant greater change in velocity of the head in the sagittal plane. In agreement with current literature, males and females demonstrate differences in their ability to stabilize the head in dynamic situations. This data suggests even female competitive rugby players demonstrate significant clinical factors that increase risk of concussion. Determining where differences exist in injury risk between males and female rugby athletes can help to design specific injury prevention interventions.

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https://scholar.acadiau.ca/islandora/object/theses:3357