Knee osteoarthritis (OA) is a progressive disease and a leading cause of morbidity in older adults, resulting in severe mobility limitations. While the osteoligamentous and neuromuscular systems are altered in knee OA, little data is available to illustrate an association among these systems. The objective of this dissertation was to improve our understanding of how muscle activation patterns during gait are altered across the knee OA severity spectrum and to examine how factors related to the OA process are associated with these alterations. Three independent but related studies were conducted. Muscle activation of the medial and lateral orientations of the gastrocnemii, quadriceps and hamstrings were recorded during gait using surface electromyography for all three studies. Key activation features were identified using principal component analysis. First, participants selected from a large group (n=272) of individuals classified as asymptomatic, ii) moderate ii) severe knee OA were matched for walking velocity. Significant amplitude and temporal activation characteristics were found, supporting that differences among OA severities exist and were not the result of walking velocity only. Secondly, individuals with moderate OA were sub-grouped based on structural severity determined using Kellgren-Lawrence radiographic scores (II-IV) and were compared to a velocity-matched asymptomatic group. Medial gastrocnemius, lateral hamstring and quadriceps amplitudes and temporal patterns were significantly altered by structural severity where significant activation imbalances between the lateral:medial gastrocnemii and hamstrings were found with greater structural impairment (score>II). Thirdly, individuals with moderate OA were prospectively evaluated and divided into knee effusion and no effusion groups, based on a positive bulge test. A significantly higher knee flexion angle during mid-stance, higher quadriceps amplitudes and prolonged hamstrings amplitudes were found when effusion was found. These studies showed that muscle activation patterns during walking were related to i) OA presence and severity based on functional, symptoms and radiographic evidence, ii) structural severity and iii) knee joint effusion. These findings improve our understanding of the interrelationships between alterations in joint structure and function associated with knee OA and muscle activation patterns during gait. These data can contribute to the development of gait-based metrics that can facilitate knee OA diagnosis and monitor progression.

Knee osteoarthritis is a debilitating disease causing pain and disability in adults. Biomechanical factors including obesity, abnormal magnitude and load distribution have been cited to play a role in its initiation and progression with its definite cause being multi-factorial. Total knee arthroplasty has become the treatment of choice for knee osteoarthritis and although the procedure is mostly successful, there are some patients who experience implant failures which necessitates revision surgery. Revision surgery is more complicated and thus there is the need to monitor patients who have undergone TKA so as ensure better outcomes and also address problems much earlier. Objective methods like Radiostereometric Analysis (RSA) has proven to be a good tool at diagnosing these implant failures. Inducible displacement with RSA has the potential to serve as a one-time measure to diagnose implant failures. Previous studies have applied loads to induce motion to the knee in various ways- squatting, exercising and weight-bearing on the affected limb. This was not standardized and caused wide variations in the data. This work looked at refining a device used to apply standardized loads to the knee resulting in a more portable and faster way of applying load to the joint. Gait analysis is used to assess implant function pre and post surgery. Some gait patterns have also been related to implant failure. Previous works have focussed primarily on associations between well-working implants (non-revised patients) and these gait patterns (adduction moments and flexion angles). This work focussed on any differences in the gait patterns between patients who did not undergo revision surgery and those that did. Although most parameter differences did not reach statistical differences, they point to important trends that may explain the causative factors (adduction moments) whiles others may point to the effects of disease progression (external rotation).

The progression of knee osteoarthritis (OA), the most common cause of physical disability in older adults, is influenced by muscular and biomechanical factors. Reliability of muscular and biomechanical measures, including knee muscle strength and limb alignment, is critical. Furthermore, conservative interventions that slow the course of OA disease progression and prevent disability are urgently needed. The objectives of this thesis were to: 1) investigate the reliability of measures of knee muscle strength and alignment in persons with knee OA, and 2) determine the influence of an exercise intervention targeting hip muscles on knee joint loading in those with medial knee OA. In the first study reliability of knee muscle strength measures was evaluated within one testing session in 40 persons with knee OA. Isometric and isokinetic peak torque values for the quadriceps and hamstring muscles demonstrated high degrees of intra-session reliability. Reliability of lower limb alignment measures was determined following a bone landmark-based approach with use of a computer program. Excellent reliability coefficients were found which compared favorably with reliability of manual measures from schematics of limb deformities drawn with AutoCAD® software. When the computer method was applied to 100 full-limb radiographs of persons with or at risk for knee OA, alignment measures demonstrated high inter- and intra-reader reliability. Hip muscle weakness may influence loading of the medial knee compartment. Hip abductor strength was evaluated in 40 individuals with medial compartment knee OA in comparison to a control group of 40 healthy older adults. The effect of an 8-week home-based hip abductor strengthening program on the knee adduction moment was also assessed in this group with knee OA, compared with the control group which received no intervention. Following the exercise program the OA group demonstrated improvements in hip abductor strength and functional performance on a sit-to-stand task. There were no changes in the knee adduction moment. Thus, hip muscle strengthening did not influence joint loading, but may improve function in persons with knee OA. Results from this thesis provide increased understanding of knee OA, from muscular and biomechanical perspectives, in the areas of measurement reliability and exercise intervention. / Thesis (Ph.D, Rehabilitation Science) -- Queen's University, 2008-09-25 01:29:13.675

Rodent models are being extensively used to investigate the effects of traumatic injuryand to develop and assess the mechanisms of repair and regeneration. We presentquantitative assessment of 2D kinematics of overground walking and for the first time3D joint angle kinematics of all four limbs during treadmill walking in the intact and inincomplete spinal cord contusion injured (iSCI) adult female Long Evans rats. Phaserelationship between joint angles on a cycle-by-cycle basis and interlimb footfalls areassessed using a simple technique. Electromyogram (EMG) data from major flexor andextensor muscles for each of the hindlimb joints and elbow extensor muscles of theforelimbs synchronized to the 3D kinematics is also obtained in intact rats. EMG activityindicates specific relationships of the neural activity to joint angle kinematics. We findthat the ankle flexors as well as the hip and elbow extensors maintain constant burstduration with changing cycle duration. Overground walking kinematics providesinformation on stance width (SW), stride length (SL) and hindfoot rotation (Rot). SW andRot increased in iSCI rats. Treadmill walking kinematics provides information on jointangle trajectories. In iSCI rats double burst pattern in ankle angle as seen in intact ratsis lost and knee extension and range are reduced. Intra and interlimb coordination isimpaired. Left-right interlimb coordination and forelimb kinematics are not alteredsignificantly. In iSCI rats, maximum flexion of the knee during swing occurs in phasewith the hip as opposed to knee flexion preceeding hip flexion in intact rats. A mildexercise regimen in intact rats over eight weeks does not alter the kinematics.

The aim of the current study is to investigate novel therapeutic/treatment methods and outcome measurement for children with Idiopathic Toe Walking (ITW). Fifteen typically developing (TD) children and 15 children with ITW, aged between 4 to 10 years old, participated. The participants performed a gait exam including 30 barefoot walking trials over three 4-meter walkways before and after a whole-body vibration intervention. Vibration perception threshold tests were also conducted before and after the vibration intervention. In the gait exams, each of the walking surfaces represented a different tactile stimulus and the vibration intervention included standing on a whole body vibration platform for 60 seconds. Kinematics were collected at 100 Hz with a seven-camera 3-D motion analysis system. Walking surface and vibration intervention were the independent variables. Temporal-spatial gait parameters such as velocity, cadence, step length, and step width were measured. Heel rise occurrence (HR32) and vibration perception threshold (VPT) were also calculated as dependent variables. Walking surface significantly altered the gait parameter of both TD children and children with ITW. Vibration intervention altered the VPT scores of both TD children and children with ITW. Manipulated surface and excessive vibration may be important in the development of therapeutic/treatment methods for children with Idiopathic Toe Walking. HR32 is a novel calculation designed to distinguish on aspect of the toe-walking gait pattern. It significantly identified toe-walking patterns and quantified treatment results. Children with ITW appeared to have less toe-walking on the gravel surface. Walking on gravel surface is a potential novel method to reduce toe-walking immediately with no negative after-effects.

Feature extraction is the most critical step in any human gait recognition system. Although gait is a dynamic process yet the static body parameters also play an important role in characterizing human gait. A few studies were performed in the past to assess the comparative relevance of static and dynamic gait features. There is, however, a lack of work in comparative performance analysis of dynamic gait features from different parts of the silhouettes in an appearance based setup. This dissertation presents a comparative study of dynamic features extracted from legs, arms and shoulders for gait recognition. Our study partially supports the general notion of leg motion being the most important determining factor in gait recognition. But it is also observed that features extracted from upper arm and shoulder area become more significant in some databases. The usefulness of the study hinges on the fact that lower parts of the leg are generally more noisy due to a variety of variations such as walking surface, occlusion and shadows. Dynamic features extracted from the upper part of the silhouettes posses significantly higher discriminatory power in such situations. In other situations these features can play a complementary role in the gait recognition process. We also propose two new feature extraction methods for gait recognition. The new methods use silhouette area signals which are easy and simple to extract. A significant performance increase is achieved by using the new features over the benchmark method and recognition results compare well to the other current techniques. The simplicity and compactness of the proposed gait features is their major advantage because it entails low computational overhead.

Feature extraction is the most critical step in any human gait recognition system. Although gait is a dynamic process yet the static body parameters also play an important role in characterizing human gait. A few studies were performed in the past to assess the comparative relevance of static and dynamic gait features. There is, however, a lack of work in comparative performance analysis of dynamic gait features from different parts of the silhouettes in an appearance based setup. This dissertation presents a comparative study of dynamic features extracted from legs, arms and shoulders for gait recognition. Our study partially supports the general notion of leg motion being the most important determining factor in gait recognition. But it is also observed that features extracted from upper arm and shoulder area become more significant in some databases. The usefulness of the study hinges on the fact that lower parts of the leg are generally more noisy due to a variety of variations such as walking surface, occlusion and shadows. Dynamic features extracted from the upper part of the silhouettes posses significantly higher discriminatory power in such situations. In other situations these features can play a complementary role in the gait recognition process. We also propose two new feature extraction methods for gait recognition. The new methods use silhouette area signals which are easy and simple to extract. A significant performance increase is achieved by using the new features over the benchmark method and recognition results compare well to the other current techniques. The simplicity and compactness of the proposed gait features is their major advantage because it entails low computational overhead.

Anti-pronation taping is commonly used by clinicians in the management of lower limb musculoskeletal pain and injury. Despite its frequent use in the clinical setting the mechanism(s) underlying its efficacy is not completely understood. For example, there is evidence that anti-pronation taping produces a biomechanical effect, but there has been little investigation of other mechanisms such as neurophysiological or psychological effects. Additionally, studies to date have been performed in mostly asymptomatic populations and have focused on the initial effect of tape (i.e. immediately following application and through a short duration of activity). Improved understanding of the underlying physiological mechanism(s) of anti-pronation tape is likely to facilitate improved knowledge of the technique, which may optimise its clinical application and contribute to clinical selection guidelines. The aims of this thesis were developed to address several of the limitations in the current anti-pronation taping literature. To facilitate an investigation of the comparative initial physiological effect of anti-pronation tape in a symptomatic and asymptomatic population, the first aim of this thesis was to compare neuromotor control (control of muscle activation and movement patterns) of gait, foot posture and foot mobility between asymptomatic individuals and individuals with a history of exercise related leg pain. The second aim of this thesis was to investigate the initial physiological effects of anti-pronation tape, specifically its neurophysiological (i.e. effect on muscle activation patterns) and biomechanical (i.e. effect on movement patterns, foot posture, foot mobility) effects. Thirdly this thesis aimed to investigate the duration of these initial physiological effects following tape removal. The fourth and fifth aims were to investigate the long term biomechanical and neurophysiological effects of anti-pronation taping i.e. following continual use over a clinically relevant period. In the first instance our aim was to investigate the effect of continual use on neuromotor control of gait, foot posture and foot mobility, and secondly to investigate the effect of continual use on the technique’s initial neurophysiological and biomechanical effects. Individuals with exercise related leg pain demonstrated lower activation of gluteus medius and lateral gastrocnemius during gait, but we observed no differences in lower limb movement patterns or foot posture and foot mobility between the two groups. The initial effect of tape was similar in individuals with and without exercise related leg pain. Specifically application of tape produced a reduction in activation of tibialis posterior, tibialis anterior and medial gastrocnemius, and increased activation of peroneus longus. There was a reduction in foot mobility, ankle plantarflexion and abduction excursion and an increase in ankle dorsiflexion and adduction excursion. Reduced muscle activation and increased motion was also observed at more proximal segments (knee, hip, pelvis), but were of smaller magnitude than at the foot and ankle. Changes in foot mobility, ankle kinematics and leg muscle activity did not continue following the removal of tape, but at more proximal segments (i.e. pelvis, hip and knee) small changes in kinematics and muscle activity were observed following the removal of tape. In regards to long term effects, continual use of tape for approximately 12 days produced a small increase in arch height when compared to a control. We did not observe a change in muscle activation or motion patterns, nor did continual use of the technique influence its initial neurophysiological or biomechanical effects (i.e. reduction in muscle activity, reduction in foot mobility, altered lower limb motion). The studies from this thesis provide evidence that anti-pronation tape should be considered in the management of individuals where reduced midfoot mobility, control of ankle motion or reduced activation of the leg muscles is desired, regardless of symptomatic status. When applied for approximately 12 days, anti-pronation tape produced a small increase in arch height ratio, but no alteration in neuromotor control. We are not aware of any definitive data on what constitutes a clinically meaningful increase in arch height, but results from a published case series suggests that our findings of a small increase in arch height may be clinically relevant for the treatment of lower extremity overuse injuries. Continual use of tape for a clinically relevant period does not alter its initial effects on foot posture and mobility or neuromotor control during gait. It would appear that the initial effects of anti-pronation tape are robust even after continuous use over a period of 11 days.

Anti-pronation taping is commonly used by clinicians in the management of lower limb musculoskeletal pain and injury. Despite its frequent use in the clinical setting the mechanism(s) underlying its efficacy is not completely understood. For example, there is evidence that anti-pronation taping produces a biomechanical effect, but there has been little investigation of other mechanisms such as neurophysiological or psychological effects. Additionally, studies to date have been performed in mostly asymptomatic populations and have focused on the initial effect of tape (i.e. immediately following application and through a short duration of activity). Improved understanding of the underlying physiological mechanism(s) of anti-pronation tape is likely to facilitate improved knowledge of the technique, which may optimise its clinical application and contribute to clinical selection guidelines. The aims of this thesis were developed to address several of the limitations in the current anti-pronation taping literature. To facilitate an investigation of the comparative initial physiological effect of anti-pronation tape in a symptomatic and asymptomatic population, the first aim of this thesis was to compare neuromotor control (control of muscle activation and movement patterns) of gait, foot posture and foot mobility between asymptomatic individuals and individuals with a history of exercise related leg pain. The second aim of this thesis was to investigate the initial physiological effects of anti-pronation tape, specifically its neurophysiological (i.e. effect on muscle activation patterns) and biomechanical (i.e. effect on movement patterns, foot posture, foot mobility) effects. Thirdly this thesis aimed to investigate the duration of these initial physiological effects following tape removal. The fourth and fifth aims were to investigate the long term biomechanical and neurophysiological effects of anti-pronation taping i.e. following continual use over a clinically relevant period. In the first instance our aim was to investigate the effect of continual use on neuromotor control of gait, foot posture and foot mobility, and secondly to investigate the effect of continual use on the technique’s initial neurophysiological and biomechanical effects. Individuals with exercise related leg pain demonstrated lower activation of gluteus medius and lateral gastrocnemius during gait, but we observed no differences in lower limb movement patterns or foot posture and foot mobility between the two groups. The initial effect of tape was similar in individuals with and without exercise related leg pain. Specifically application of tape produced a reduction in activation of tibialis posterior, tibialis anterior and medial gastrocnemius, and increased activation of peroneus longus. There was a reduction in foot mobility, ankle plantarflexion and abduction excursion and an increase in ankle dorsiflexion and adduction excursion. Reduced muscle activation and increased motion was also observed at more proximal segments (knee, hip, pelvis), but were of smaller magnitude than at the foot and ankle. Changes in foot mobility, ankle kinematics and leg muscle activity did not continue following the removal of tape, but at more proximal segments (i.e. pelvis, hip and knee) small changes in kinematics and muscle activity were observed following the removal of tape. In regards to long term effects, continual use of tape for approximately 12 days produced a small increase in arch height when compared to a control. We did not observe a change in muscle activation or motion patterns, nor did continual use of the technique influence its initial neurophysiological or biomechanical effects (i.e. reduction in muscle activity, reduction in foot mobility, altered lower limb motion). The studies from this thesis provide evidence that anti-pronation tape should be considered in the management of individuals where reduced midfoot mobility, control of ankle motion or reduced activation of the leg muscles is desired, regardless of symptomatic status. When applied for approximately 12 days, anti-pronation tape produced a small increase in arch height ratio, but no alteration in neuromotor control. We are not aware of any definitive data on what constitutes a clinically meaningful increase in arch height, but results from a published case series suggests that our findings of a small increase in arch height may be clinically relevant for the treatment of lower extremity overuse injuries. Continual use of tape for a clinically relevant period does not alter its initial effects on foot posture and mobility or neuromotor control during gait. It would appear that the initial effects of anti-pronation tape are robust even after continuous use over a period of 11 days.

Anti-pronation taping is commonly used by clinicians in the management of lower limb musculoskeletal pain and injury. Despite its frequent use in the clinical setting the mechanism(s) underlying its efficacy is not completely understood. For example, there is evidence that anti-pronation taping produces a biomechanical effect, but there has been little investigation of other mechanisms such as neurophysiological or psychological effects. Additionally, studies to date have been performed in mostly asymptomatic populations and have focused on the initial effect of tape (i.e. immediately following application and through a short duration of activity). Improved understanding of the underlying physiological mechanism(s) of anti-pronation tape is likely to facilitate improved knowledge of the technique, which may optimise its clinical application and contribute to clinical selection guidelines. The aims of this thesis were developed to address several of the limitations in the current anti-pronation taping literature. To facilitate an investigation of the comparative initial physiological effect of anti-pronation tape in a symptomatic and asymptomatic population, the first aim of this thesis was to compare neuromotor control (control of muscle activation and movement patterns) of gait, foot posture and foot mobility between asymptomatic individuals and individuals with a history of exercise related leg pain. The second aim of this thesis was to investigate the initial physiological effects of anti-pronation tape, specifically its neurophysiological (i.e. effect on muscle activation patterns) and biomechanical (i.e. effect on movement patterns, foot posture, foot mobility) effects. Thirdly this thesis aimed to investigate the duration of these initial physiological effects following tape removal. The fourth and fifth aims were to investigate the long term biomechanical and neurophysiological effects of anti-pronation taping i.e. following continual use over a clinically relevant period. In the first instance our aim was to investigate the effect of continual use on neuromotor control of gait, foot posture and foot mobility, and secondly to investigate the effect of continual use on the technique’s initial neurophysiological and biomechanical effects. Individuals with exercise related leg pain demonstrated lower activation of gluteus medius and lateral gastrocnemius during gait, but we observed no differences in lower limb movement patterns or foot posture and foot mobility between the two groups. The initial effect of tape was similar in individuals with and without exercise related leg pain. Specifically application of tape produced a reduction in activation of tibialis posterior, tibialis anterior and medial gastrocnemius, and increased activation of peroneus longus. There was a reduction in foot mobility, ankle plantarflexion and abduction excursion and an increase in ankle dorsiflexion and adduction excursion. Reduced muscle activation and increased motion was also observed at more proximal segments (knee, hip, pelvis), but were of smaller magnitude than at the foot and ankle. Changes in foot mobility, ankle kinematics and leg muscle activity did not continue following the removal of tape, but at more proximal segments (i.e. pelvis, hip and knee) small changes in kinematics and muscle activity were observed following the removal of tape. In regards to long term effects, continual use of tape for approximately 12 days produced a small increase in arch height when compared to a control. We did not observe a change in muscle activation or motion patterns, nor did continual use of the technique influence its initial neurophysiological or biomechanical effects (i.e. reduction in muscle activity, reduction in foot mobility, altered lower limb motion). The studies from this thesis provide evidence that anti-pronation tape should be considered in the management of individuals where reduced midfoot mobility, control of ankle motion or reduced activation of the leg muscles is desired, regardless of symptomatic status. When applied for approximately 12 days, anti-pronation tape produced a small increase in arch height ratio, but no alteration in neuromotor control. We are not aware of any definitive data on what constitutes a clinically meaningful increase in arch height, but results from a published case series suggests that our findings of a small increase in arch height may be clinically relevant for the treatment of lower extremity overuse injuries. Continual use of tape for a clinically relevant period does not alter its initial effects on foot posture and mobility or neuromotor control during gait. It would appear that the initial effects of anti-pronation tape are robust even after continuous use over a period of 11 days.