Browsing by Subject "Running"

It is possible to investigate in vivo musculoskeletal biomechanics using multimodal medical imaging techniques; however, the analysis of medical image sets is often time-prohibitive. In this dissertation, I outline various projects that utilize magnetic resonance imaging (MRI) scans acquired before and after exercise to quantify cartilage thickness changes incurred by the loading activity. A better understanding of cartilage mechanics is crucial for prediction and prevention efforts related to osteoarthritis, patellofemoral pain, and other musculoskeletal conditions. While this cartilage "stress test'' protocol has been used in the past to investigate knee, ankle, and spine mechanics, this work expands the methodology to the shoulder and hip joints and further addresses the impact of various exercises on the knee joint in different subject populations. For instance, I outline how patellofemoral cartilage deforms after a series of single-legged hops in anterior cruciate ligament-deficient and intact knees, how body mass index impacts patellofemoral cartilage strain and T1rho relaxation times in the context of walking, how tibial cartilage T1rho relaxation times change over the course of the day due to activities of daily living, and how pushups affect glenohumeral cartilage. I also discuss the development and validation of a semi-automated technique to isolate bones from MRIs, which reduces the time required for manual segmentation by approximately 75% and thus significantly improves research efficiency. As an expansion of the semi-automatic segmentation work, I will cover how I developed a technique to assess the minimum moment of inertia along the femoral neck from clinical computed tomography (CT) scans, with the goal of understanding relative fracture risks between individuals with and without diabetes. Finally, I quantify running-induced changes in knee cartilage thickness and composition (as measured by T1rho relaxation times), as well as changes in hip joint bone-to-bone distances and hip cartilage T1rho relaxation times. Running is a known activity linked to patellofemoral pain, yet the underlying etiology of this condition is unknown. As both knee and hip kinematics have been linked to patellofemoral pain, the goal was to assess how running influences these joints biomechanically and biochemically to better understand why people suffer from patellofemoral pain.