Abstract Background: Osteoarthritis (OA) is a prevalent joint disease causing significant disability, particularly in the knee often treated end-stage with joint replacement surgery. While partial knee arthroplasty (PKA) is noted for quicker recovery and better functionality compared to total knee arthroplasty (TKA), its underutilization highlights a gap in surgical decision-making, driven by a lack of objective data on pre-operative functional differences. Methods: This prospective observational study, conducted from November 2023 to April 2024 at St. Joseph’s Healthcare Hamilton, included 34 end-stage OA patients scheduled for knee arthroplasty. Participants underwent pre-operative functional assessments using markerless motion capture technology to analyze gait and mobility during walking and sit-to-stand tests. Results: The study found no significant differences in basic gait and sit-to-stand metrics between the PKA and TKA groups at a preferred pace. However, at a faster pace, PKA patients demonstrated greater adaptability, showing significant increases in peak stance knee flexion, knee flexion excursions, and stride length, compared to TKA patients whose gait patterns remained consistent across speeds. Conclusion: PKA patients exhibit greater functional adaptability in their pre-operative state, suggesting potential underestimation of their capabilities in current surgical evaluations. Incorporating varied-pace walking tests in pre-operative assessments may provide deeper insights into functional capabilities, influencing more tailored surgical decisions and potentially increasing the application of PKA in suitable candidates. / Thesis / Master of Applied Science (MASc)

No / Falls in the elderly are a major cause of serious injury and mortality. Impaired and absent stereopsis may be a significant risk factor for falls or hip fracture, although data from epidemiological studies are not consistent. Previous laboratory based studies, however, do suggest that stereoacuity is an important factor in adaptive gait. The present study investigates how acute impairment of stereopsis, through monocular blur of differing levels, ranging from 0.50 diopter (D) to a monovision correction affected gait when negotiating a raised surface in elderly subjects. Eleven elderly subjects (73.3 3.6 years) walked up to and negotiated a raised surface under nine visual conditions, binocular vision, one eye occluded and 0.50 D, 1.00 D and monovision correction (mean 2.50 D 0.20 D) with blur and occlusion either over the dominant or non-dominant eye. Analysis focused on foot positioning and toe clearance parameters. There was no effect of ocular dominance on any parameters. Monocular blur impaired stereopsis (p 0.01), with more minor effects on high and low contrast acuity. Vertical and horizontal lead limb toe clearance both increased under all levels of monocular blur including the lowest level of 0.50 DBlur (p 0.03) and monovision correction led to toe clearance levels similar to that found with occlusion of one eye. Findings demonstrated that even small amounts of monocular blur can lead to a change in gait when negotiating a raised surface, suggesting acute monocular blur affected the ability to accurately judge the height of a step in the travel path. Further work is required to investigate if similar adaptations are used by patients with chronic monocular blur.

One possible solution to common running related injuries is to transition runners from a rearfoot strike during initial contact to a midfoot strike. Natural rearfoot strike runners were studied to see if a modified elliptical trainer could be used to alter their running pattern to that of a midfoot strike runner. Their results were compared to subjects who ran on a non-modified elliptical trainer. After training on the modified elliptical trainer, subjects demonstrated a decrease in foot angle at initial contact when attempting to run with a midfoot strike. Training did not affect all kinetic metrics or stride frequency. However, the kinematic change suggests that there may be an impact on running energetics. Training on the modified elliptical trainer resulted in improved midfoot strike kinematics in natural rearstrike runners when they attempted run in a midfoot strike pattern.

Title: Experimental investigation of human gait analysis parameters Objective: The main objective of diploma thesis was an experiment, that examined kinematic and dimensional parameters of human gait which was captured by several cameras and acquired data was recorded in 2D and 3D measurement. Secondary objective was to compare and statistically evaluate data acquired from measurement. The objective of analysis was to discover and describe possible regularities, patterns of human gait and other connections in investigated subjects. Methods: Comparative method was used in the thesis. The purpose of the experiment was to compare parameters measured during attempts of every subject that were conducted under different conditions (different velocity, dressed, undressed, in the environment of 2D and 3D recording) and also to compare different subjects with each other. Results: In the experiment we observed that it is possible to prove the relation between the length of a step and the velocity of gait and also the relation between the change in the body height and the velocity of human gait by three dimensional recording of gait and its analysis. This contention was confirmed in the comparison dressed and undressed subjects. The result of the experiment was, that with increasing velocity of gait is...

Title Gait Analysis in Adolescents with Idiopathic Scoliosis: A Systematic Review. Aim The role of spine is vital as a gait stabilizer. Gait analysis may provide a more holistic view of how the body behaves to idiopathic scoliosis among adolescents. The aim of this thesis is to review the effectiveness and validity of gait analysis in examining AIS, and secondly to assess how the gait of AIS patients differ from adolescents without scoliosis. Method A systematic review of the topic was conducted. Information was gathered from six e-databases, and seventeen articles were selected, of which seven focusing solely on AIS subjects (i.e. non-comparative) and ten were focusing on AIS in relation to control subjects (i.e. comparative). Results Spatio-temporal (STP), kinematic, kinetic and EMG parameters show significant changes in AIS subjects during walking. But variations between results, lack of data for certain parameters and no significant relationship between gait parameters and scoliosis was also seen. Furthermore, AIS subjects differ in performance compared to non-scoliosis adolescents in at least one gait parameter across all studies. This includes abnormalities in muscle activity, less economical use of the body, poorer performance in kinematic parameters and differences in STP such as step...

Community locomotion is threatened when older individuals are required to negotiate obstacles, which place considerable stress on the musculoskeletal system. The vulnerability of older adults during challenging locomotor tasks is further compromised by age-related strength decline and muscle atrophy. The first study in this investigation determined the relationship between the major muscle groups of the lower body and challenging locomotor tasks commonly found in the community environment of older adults. Twenty-nine females and sixteen males aged between 62 and 88 years old (68.2 ±6.5) were tested for the maximal voluntary contraction (MVC) strength of the knee extensors and 1-RM for the hip extensors, flexors, adductors, abductors, knee extensors and flexors and ankle plantar flexors. Temporal measurements of an obstacle course comprising four gait tasks set at three challenging levels were taken. The relationship between strength and the obstacle course dependent measures was explored using linear regression models. Significant associations (p≤0.05) between all the strength measures and the gait performances were found. The correlation values between strength and obstructed gait (r = 0.356-0.554) and the percentage of the variance explained by strength (R2 = 13%-31%), increased as a function of the challenging levels, especially for the stepping over and on and off conditions. While the difficulty of community older adults to negotiate obstacles cannot be attributed to a single causal pathway, the findings of the first study showed that strength is a critical requirement. That the magnitude of the association increased as a function of the challenging levels, suggests that interventions aimed at improving strength would potentially be effective in helping community older adults to negotiate environmental gait challenges. In view of the findings of the first study, a second investigation determined the effectiveness of a progressive resistance-training program on obstructed gait tasks measured under specific laboratory conditions and on an obstacle course mimicking a number of environmental challenges. The time courses of strength gains and neuromuscular mechanisms underpinning the exercise-induced strength improvements in community-dwelling older adults were also investigated. The obstructed gait conditions included stepping over an obstacle, on and off a raised surface, across an obstacle and foot targeting. Forty-three community-living adults with a mean age of 68 years (control =14 and experimental=29) completed a 24-week progressive resistance training program designed to improve strength and induce hypertrophy in the major muscles of the lower body. Specific laboratory gait kinetics and kinematics and temporal measures taken on the obstacle course were measured. Lean tissue mass and muscle activation of the lower body muscle groups were assessed. The MVC strength of the knee extensors and 1-RM of the hip extension, hip flexion, knee extension, knee flexion and ankle plantar flexion were measured. A 25% increase on the MVC of the knee extensors (p≤0.05) was reported in the training group. Gains ranging between 197% and 285% were recorded for the 1-RM exercises in the trained subjects with significant improvements found throughout the study (p≤0.05). The exercise-induced strength gains were mediated by hypertrophic and neural factors as shown by 8.7% and 27.7% increases (p≤0.05) in lean tissue mass and integrated electromyographic activity, respectively. Strength gains were accompanied by increases in crossing velocity, stride length and reductions in stride duration, stance and swing time for all gait tasks except for the foot targeting condition. Specific kinematic variables associated with safe obstacle traverse such as vertical obstacle heel clearance, limb flexion, horizontal foot placements prior to and at post obstacle crossing and landing velocities resulted in an improved crossing strategy in the experimental subjects. Significant increases in the vertical and anterior-posterior ground reaction forces accompanied the changes in the gait variables. While further long-term prospective studies of falls rates would be needed to confirm the benefits of lower limb enhanced strength, the findings of the present study provide conclusive evidence of significant improvements to gait efficiency associated with a systematic resistance-training program. It appears, however, that enhanced lower body strength has limited effects on gait tasks involving a dynamic balance component. In addition, due to the larger strength-induced increases in voluntary activation of the leg muscle compared to relatively smaller gains in lean tissue mass, neural adaptations appear to play a greater contributing role in explaining strength gains during the current resistance training protocol.

Human activity analysis has attracted great interest from computer vision researchers due to its promising applications in many areas such as automated visual surveillance, computer-human interactions, and motion-based identification and diagnosis. This dissertation presents work in two areas: general human activity recognition from video, and human activity analysis for the purpose of identifying pathological gait from both 3D captured data and from video. Even though the research in human activity recognition has been going on for many years, still there are many issues that need more research. This includes the effective representation and modeling of human activities and the segmentation of sequences of continuous activities. In this thesis we present an algorithm that combines shape and motion features to represent human activities. In order to handle the activity recognition from any viewing angle we quantize the viewing direction and build a set of Hidden Markov Models (HMMs), where each model represents the activity from a given view. Finally, a voting based algorithm is used to segment and recognize a sequence of human activities from video. Our method of representing activities has good attributes and is suitable for both low resolution and high resolution video. The voting based algorithm performs the segmentation and recognition simultaneously. Experiments on two sets of video clips of different activities show that our method is effective. Our work on identifying pathological gait is based on the assumption of gait symmetry. Previous work on gait analysis measures the symmetry of gait based on Ground Reaction Force data, stance time, swing time or step length. Since the trajectories of the body parts contain information about the whole body movement, we measure the symmetry of the gait based on the trajectories of the body parts. Two algorithms, which can work with different data sources, are presented. The first algorithm works on 3D motion-captured data and the second works on video data. Both algorithms use support vector machine (SVM) for classification. Each of the two methods has three steps: the first step is data preparation, i.e., obtaining the trajectories of the body parts; the second step is gait representation based on a measure of gait symmetry; and the last step is SVM based classification. For 3D motion-captured data, a set of features based on Discrete Fourier Transform (DFT) is used to represent the gait. We demonstrate the accuracy of the classification by a set of experiments that shows that the method for 3D motion-captured data is highly effective. For video data, a model based tracking algorithm for human body parts is developed for preparing the data. Then, a symmetry measure that works on the sequence of 2D data, i.e. sequence of video frames, is derived to represent the gait. We performed experiments on both 2D projected data and real video data to examine this algorithm. The experimental results on 2D projected data showed that the presented algorithm is promising for identifying pathological gait from video. The experimental results on the real video data are not good as the results on 2D projected data. We believe that better results could be obtained if the accuracy of the tracking algorithm is improved.

The kinematic motor redundancy of the human legs provides more local degrees of freedom than are necessary to achieve low degree of freedom performance variables like leg length and orientation. The purpose of this dissertation is to investigate how the neuromuscular skeletal system simplifies control of a kinematically redundant system to achieve stable locomotion under different conditions. I propose that the neuromuscular skeletal system minimizes step to step variance of leg length and orientation while allowing segment angles to vary within the set of acceptable combinations of angles that achieves the desired leg length and orientation. I find that during human hopping, control of the locomotor system is organized hierarchically such that leg length and orientation are achieved by structuring segment angle variance. I also found that leg length and leg orientation was minimized for a variety of conditions and perturbations, including frequency, constrained foot placement, and different speeds. The results of this study will give valuable information on interjoint compensation strategies used when the locomotor system is perturbed. This work also provides evidence for neuromuscular system strategies in adapting to novel, difficult tasks. This information can be extended to give insight into new and different areas to focus on during gait rehabilitation of humans suffering from motor control deficits in movement and gait.

Thesis (Ph. D.)--University of Oregon, 2001. / Includes vita and abstract. Includes bibliographical references (leaves 191-196). Also available for download via the World Wide Web; free to University of Oregon users.

The portability, ease of use and improved accuracy of miniature inertial sensors brought by current microelectromechanical system (MEMS) technology has inspired researchers to develop human movement monitoring system with body-fixed sensors. Although a large number of studies have attempted to explore the use of miniature inertial sensors in estimating walking speed for the past two decades, there still remain some questions regarding applying inertial sensors in estimating walking speed under different walking conditions and for different subject populations. In this thesis, I focus on evaluating and improving the performance of a shank-mounted mounted inertial measurement unit (IMU) based walking speed estimation method. My research can be divided into four parts. The first part was a systematic review regarding the state of the art of current development of the inertial sensor based walking speed estimation method. A total of 16 articles were fully reviewed in terms of sensor specification, sensor attachment location, experimental design and spatial parameter estimation algorithm. In the second part, a comprehensive performance evaluation was conducted, which included the treadmill and overground walking experiments with constraint on the walking speed, stride length and stride frequency. A systematic error was observed in the error analysis of this study, which was adjusted by subtracting the bias by linear regression. In the third part, a post-stroke subject overground walking experiment was carried out with an improved walking speed estimation method that reduced the systematic error caused by previous false initial speed assumption. In addition to walking speed estimation, the gait asymmetry for post-stroke hemiparetic gait was also evaluated with the proposed method. The last part was the sensor error model analysis. We elaborately analyzed and discussed the estimation errors involved in this method in order to completely understand the sensor error compensation in walking speed estimation algorithm design. Two existing sensor error models and one newly developed sensor error model were compared with the treadmill walking experiment, which demonstrated the effect of each sensor error component on the estimation result and the importance of the sensor error model selection. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2011-08-23 19:38:16.965