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DISSERTATION ABSTRACT Li Jin Doctor of Philosophy Department of Human Physiology March 2018 Title: Kinematic and Kinetic Analysis of Walking and Running across Speeds and Transitions between Locomotion States Walking and running are general locomotion activities for human beings. Basic gait patterns and whole body center of mass (COM) dynamic patterns are distinctly different between them. Lower extremity joint mechanics patterns could reflect musculoskeletal coordination characteristics. Change of locomotion tasks and speeds can affect lower extremity joint kinematic and kinetic characteristics, and progression of age may also affect these characteristics. Little is known about change of locomotion tasks and speeds effects on lower extremity joint level kinetic characteristics, and whether there is a connection between COM system and lower extremity system. To address this, twenty healthy subjects were recruited to participate in a series of treadmill tests, including walking (0.8 – 2.0 m/s, with 0.2 m/s intervals), running (1.8 – 3.8 m/s, with 0.4 m/s intervals) and gait mode transition from walking to running, and from running to walking (between 1.8 – 2.4 m/s, 0.1 m/s2). Three-dimensional kinematic and kinetic data were collected in all locomotion tests and used to calculate and analyze outcome variables for lower extremity joints and the COM system across different conditions. Results indicate that change of locomotion speeds significantly affect joint level kinetic characteristics within both walking and running locomotion states. Different locomotion task demands (walking vs. running) require fundamental alteration of lower extremity joint level kinetic patterns, even at the same locomotion speed. Progression of age also affects lower extremity joint level kinematic and kinetic patterns in walking and running across speeds. Additionally, stance phase an energy generation and transfer phenomenon occurred between the distal and proximal joints of the lower extremity in both walk-to-run and run-to-walk transitions. Lastly, a connection exists between whole body COM oscillation patterns and lower extremity joint level kinetic characteristics in running. These findings serve to further clarify the mechanisms involved in change of locomotion tasks and speeds effects on lower extremity joint kinetic patterns, and further establish a connection between the COM system and the lower extremity system. These findings may be beneficial for future foot-ankle assistive device development, potential optimization of gait efficiency and performance enhancement. This dissertation includes previously published and unpublished coauthored material.

Thesis (Ph. D.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. "This dissertation includes unpublished co-authored material"--P. v. Includes bibliographical references (leaves 119-128). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.

Computational models of musculoskeletal joints and limbs can provide useful information about joint mechanics. Validated models can be used as a predictive device for understanding joint function and serve as a clinical tool for predicting the outcome of surgical procedures. A new computational modeling approach was developed for simulating joint kinematics that are dictated by bone/joint anatomy, ligamentous constraints, and applied loading.Three-dimensional computational models of the lower leg were created. Model development involved generating three-dimensional surfaces from CT images, followed by importing these surfaces into SolidWorks and COSMOSMotion. ThroughSolidWorks and COSMOSMotion, each bone surface was created into a solid object and positioned, necessary components added, and simulations executed. Three dimensional contacts inhibited intersection of the bones during motion. Ligaments were represented as linear springs. Model predictions were then validated by comparison to three different previously performed cadaver studies (syndesmotic injury study, inversion stability study, and mechanical laxity study) and one simultaneously performed cadaver study (anterior drawer test).In the syndesmotic injury study, the relative motion between the tibia and fibula in intact, transected, and repaired states was measured under the application of an external rotation of the ankle. The inversion stability study focused on the elongation behavior of lateral ankle ligaments and inversion range of motion during the application of an applied load. The mechanical laxity study focused on differences in anterior/posterior and inversion/eversion movement in intact and transected states. Each computational simulation was placed under the same conditions as its respective cadaver study and revealed a capability to predict behaviors in each case. The syndesmotic injury model was able to predict tibia1 rotation, fibular rotation, and anterior/posterior displacement. In the inversion simulation, calcaneofibular ligament extension and angles of inversion compared well. The laxity study showed increases in anteroposter motion after the transactions of the ATFL and CFL; and diffenences in inversion after the transaction of the CFL. The Anterior Drawer simulation produced similar ligament elongations and loads when compared to cadaver studies.Overall, the computational models were able to predict joint kinematics of the lower leg with particular focus on the ankle complex. Additional parameters can be calculated through such models that are not easily obtained experimentally such as ligament forces, force transmission across joints, and three-dimensional movement of all bones.

Dynamic assessment of three-dimensional (3D) joint kinematics is essential for understanding normal joint function as well as the effects of injury or disease. The knowledge of one or two series of bi-dimensional fluoroscopic projections of the joint in motion (mono-planar or bi-planar fluoroscopy), and the 3D model of the joint segments, were claimed to be sufficient to reconstruct the absolute and relative 6 Degrees Of Freedom (DOFs) pose of bones or prostheses in the 3D space. The software MultiTrack was developed at the Health Sciences and Technologies - Interdepartmental Center for Industrial Research (HST - ICIR) for the joint kinematics estimation with 3D Video Fluoroscopy (3DF) [1] using C++ language with ITK [2] segmentation & registration toolkit and VTK [3] visualization toolkit. An optimization procedure finds the 6 degrees of freedom pose that optimizes a metric quantifying the matching of the 3D model and its relevant projections. The metric, currently implemented in the software, is based on the contour segmentation of the object to be tracked and on the use of 3D adaptive distance maps (ADM) [4,5]. However, the contour extraction is a time consuming procedure for the user. Different methods were proposed in the literature to reduce the user interaction, each with its proper pros and cons. In the current thesis a few of the for-mentioned methods are discussed in order to evaluate each of them in terms of accuracy, speed and user dependency. At the final step the algorithm proposed by Mafhouz et al. [6], initially proposed for prostheses, is implemented inside the MultiTrack framework. To be properly characterized, the above method is tested on in vivo datasets and under various sources of error. / Η δυναμική αξιολόγηση της τρισδιάστατης (3D) κινηματικής των αρθρώσεων είναι απαραίτητη για την κατανόηση της φυσιολογικής λειτουργία των αρθρώσεων, καθώς και τις επιπτώσεις της κακώσεων ή παθήσεων . Η γνώση μιας ή δύο σειρών δυσδιάστατων ακτινοσκοπικών προβολών των αρθρώσεων σε κίνηση ( μονο - επίπεδη ή δι- επίπεδη ακτινοσκόπηση), και ενός τρισδιάστατου (3D) μοντέλου των επιμέρους τμημάτων των αρθρώσεων , κρίνεται επαρκής για να ανακατασκευαστούν τόσο οι απόλυτοι όσο και οι σχετικοί 6 βαθμοί ελευθερίας της θέσης των οστών ή των προσθετικών τμημάτων στον τρισδιάστατο χώρο. Το λογισμικό “MultiTrack” αναπτύχθηκε στις Επιστήμες Υγείας και Τεχνολογίες - Διατμηματικό Κέντρο Βιομηχανικών Ερευνών (HST-ICIR) έτσι ώστε να επιτευχθεί με ακρίβεια η εκτίμηση της κινηματικς των αρθρώσεων με τρισδιάστατη ακτινοσκόπηση (φθοροσκοπία) με βιντεοκαρέ (3DF) [1] χρησιμοποιώντας C++ γλώσσα προγραμματισμού σε συνδυασμό με τα εργαλεία κατακερματισμού & καταγραφής (segmentation & registration) ITK [2] και οπτικοποίησης (visualization) VTK [3]. Μια διαδικασία βελτιστοποίησης βρίσκει τους 6 βαθμούς ελευθερίας της θέσης που βελτιστοποιεί τη συνάρτηση ποσοτικοποίησης της συνάφειας του 3D μοντέλου και των σχετικών προβολών του. Η συνάρτηση ποσοτικοποίησης, έτσι όπως έχει υλοποιηθεί στο λογισμικό, βασίζεται στην κατάτμηση του περιγράμματος (contour segmentation) του υπό εξέταση αντικειμένου και στη χρήση τρισδιάστατων προσαρμοστικών χαρτών απόστασης (Adaptive Distance Map-ADM) [4,5]. Ωστόσο, η εξαγωγή του περιγράμματος είναι μια χρονοβόρα διαδικασία για το χρήστη. Διαφορετικές μέθοδοι έχουν προταθεί στη βιβλιογραφία για τη μείωση της αλληλεπίδρασης του χρήστη, η καθεμία με τα πλεονεκτήματα και τα μειονεκτήματα της. Στην παρούσα διπλωματική εργασία, αναλύονται μερικές από τις προαναφερθείσες μέθοδοι προκειμένου να αξιολογηθεί καθεμία από αυτές όσον αφορά την ακρίβεια, την ταχύτητα και την εξάρτηση της από το χρήστη. Στο τελικό στάδιο, ο αλγόριθμος που προτείνεται από τον Mafhouz [6] και χρησιμοποιήθηκε αρχικά για προθέσεις, υλοποιείται εντός του λογισμικού “MultiTrack”. Η παραπάνω μέθοδος για να χαρακτηριστεί πλήρως, έχει δοκιμαστεί σε in-νίνο δεδομένα και κάτω από διάφορες πηγές σφάλματος.

Total knee arthroplasty has been effective in reducing pain, but less so in restoring function, especially for activities requiring deep knee flexion. The philosophy of this dissertation was that more functionally effective and optimally designed artificial knees could be created for high flexion activities, if the knee joint kinematics and joint contact forces applied during finite element testing, knee simulator testing, and fatigue testing were more physiologically accurate. The objective of this work was to determine knee joint kinematics and contact forces that could be used in high flexion total knee replacement design and pre-clinical testing. Knee kinematics were determined during high flexion activities for total knee replacement patients and asymptomatic subjects by tracking the motion of skin-mounted sensors. In addition, a protocol was developed to determine the effect of soft tissue artefact on the accuracy of the skin-mounted sensor system in high flexion. The ranges of motion determined for the studied activities can be used as a benchmark to measure the functional success of high flexion total knee replacements. Tibiofemoral joint contact forces were estimated during high flexion activities of daily living using a simple, non-invasive, inverse dynamics based model. The accuracy of the joint contact force estimates was investigated by comparing the estimated forces to in vivo forces measured directly using implanted instrumented tibial components. The comparison showed that the model underestimates the measured axial joint contact force, most likely because the model neglects antagonistic muscle co-contraction. The measured and modeled joint contact forces and the measured knee kinematics could be used to form industry standards for knee simulator and fatigue testing to ensure that the implants are being tested physiologically. Healthy target populations can be studied using the methods outlined in this thesis to define testing standards for target populations: Kinematics can be determined as they were in this work for a group of Middle Eastern subjects, and the non-invasive inverse dynamics based model (with some consideration for the underestimation of forces) could be used to determine the tibiofemoral joint contact forces that the implant might be subjected to during activities of daily living. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2010-10-25 11:33:06.162

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Clinical decisions based on gait data obtained by optoelectronic motion capturing require profound knowledge about the repeatability of the used measurement systems and methods. The purpose of this study was to evaluate the effects of inconsistent anthropometric measurements on joint kinematics calculated with the Plug-in Gait model. Therefore, a sensitivity study was conducted to ascertain how joint kinematics output is affected to different anthropometric data input. One previously examined gait session of a healthy male subject and his anthropometric data that were assessed by two experienced examiners served as a basis for this analytical evaluation. This sensitivity study yielded a maximum difference in joint kinematics by the two sets of anthropometrics of up to 1.2°. In conclusion, this study has shown that the reliability of subjects’ anthropometrics assessed by experienced examiners has no considerable effects on joint kinematics.

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