Browsing by Author "Bruce, Olivia Leigh"

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    Tibial-fibular morphology: variation, sexual dimorphism, and mechanical implications
    (2023-05-01) Bruce, Olivia Leigh; Edwards, William Brent; Boyd, Steven Kyle; Kuo, Arthur; Roach, Koren Elaine; Jordan, Matthew James; Lenz, Amy Lorraine
    Stress fractures are common injuries among runners and military personnel associated with the mechanical fatigue of load-bearing bone. The tibia is the most frequently fractured site and females are at much greater risk than males. Bone geometry and density are hypothesized risk factors for stress fracture and are thought to contribute to the disparity in risk between sexes via their influence on bone strain magnitude which is strongly related to the rate of mechanical fatigue. However, covariation between these two complex factors and their influence on the strain environment of the tibia are not well characterised. The overarching goal of this thesis was to develop a more nuanced understanding of the mechanical implications of tibial-fibular geometry and density variations present in young active adults. A series of studies were performed utilizing a combination of advanced medical imaging, statistical approaches, gait data, and the finite element method to characterise and quantify covariations in whole-bone tibial-fibular geometry and density distributions and their influence on bone strain. Transverse diaphyseal geometry and sagittal curvature were identified as key features that likely influence stress fracture risk, demonstrating substantial effects on finite element-predicted bone strain. Additionally, the average female illustrated a narrower tibia which resulted in elevated bone strain when compared to the average male, suggesting that bone geometry likely contributes to the disparity in stress fracture risk between sexes. As we work towards improving predictive models and developing effective screening tools for stress fracture risk, these findings provide insights into key features of bone geometry and density that will need to be accurately characterised. Landmark- and anthropometric-based predictions of tibial-fibular geometry and density were not sufficiently accurate, indicating that some level of advanced medical imaging data will be necessary to generate personalised models or characterise geometry and density features associated with stress fracture risk.
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    Towards the Real-time Monitoring of Achilles Tendon Strain
    (2018-07-18) Bruce, Olivia Leigh; Edwards, William Brent; Stefanyshyn, Darren J.; Wiley, James Preston; Bertram, John Edward Arthur
    Achilles tendinopathy is an overuse injury affecting jumping athletes, associated with the accumulation of microdamage due to repetitive tendon strain. Surface and footwear modifications may influence tendon strain magnitude. The purpose of this thesis was to examine the influence of surface and footwear modifications on Achilles tendon strain during vertical countermovement jump landings and to quantify the relationship between tendon strain and accelerometer measures. The parameters were quantified for three shoes (Boost™, 55C, and 70C) and three surfaces (ACS, BC3, and MVP) using motion capture, accelerometry, and dynamometry-ultrasound measures. Surface and footwear influenced Achilles tendon strain; strain was lower in the Boost™ shoe and MVP surface conditions. Differences in strain could be due to stiffness or other material properties of the shoes and surfaces. Only weak correlations were found between tendon strain and accelerometer measures, suggesting that data obtained from accelerometers may not reflect internal loading.