Master of Physical Therapy and Doctor of Philosophy in Rehabilitation Sciences (MPTPHD)
Biomechanics and motor learning of gait modification for individuals with knee osteoarthritis
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Pain is a common symptom in patients with chronic obstructive pulmonary disease (COPD). This symptom can negatively affect physical activity levels, quality of life, and health outcomes. It has been shown that systemic inflammation, comorbidities, and symptoms (e.g., dyspnea or fatigue) may cause pain. Although previous research has determined the association between pain and the presence of comorbidities, the specific comorbidities that cause pain and other etiologic factors of pain are still unknown. Also, the interrelationships among pain, dyspnea, and fatigue and whether the presence of one symptom accentuates another remain to be examined.The overall purpose of this dissertation was to investigate the etiology of pain by exploring the pain experience, the contributors to pain, the interrelationships between pain and other symptoms, and the associations between pain and thoracic abnormalities in patients with COPD. Studies I and II established the reliability and validity of the Brief Pain Inventory (BPI), Dyspnea Inventory (DI), and Brief Fatigue Inventory (BFI) in patients with COPD. Study III determined comorbidities that caused pain as well as compared pain, fatigue, and dyspnea symptomology in patients with COPD. This study utilized a cross-sectional survey design that included the BPI, DI, BFI, General Self-efficacy Scale, Clinical COPD Questionnaire, and Comorbidities/Medication Questionnaire. Study IV investigated chest computed tomography images of patients with COPD and current/ex-smokers to examine the associations between trunk pain and thoracic vertebral deformity and arthropathy. The findings showed that the BPI, DI, and BFI were reliable and valid questionnaires to evaluate symptoms in COPD. Similar to dyspnea and fatigue, pain was also a significant symptom in patients with COPD and these three symptoms were correlated with each other. Further, the most common comorbidities that caused pain were musculoskeletal diseases. Trunk pain in patients with COPD was associated with thoracic vertebral deformities, arthropathy of thoracic joints, and hyperkyphosis.In summary, pain in COPD is associated with musculoskeletal comorbidities and there are interactions between pain and other symptoms. This dissertation provides insight into the causes of pain in patients with COPD, which can facilitate the development of pain management strategies in COPD.
Introduction: Those with knee osteoarthritis report more falls than those without, and falls present serious economic, personal and public health consequences. Dynamic balance is an important factor associated with falls risk. Current clinical tests of balance in this population have limitations to their use. Further, interventions to improve dynamic balance have had mixed results in this population, possibly since more information on dynamic balancing ability is needed for better program design. This thesis examined the assessment and treatment of dynamic balancing ability in individuals with knee osteoarthritis.Methods: The Community Balance and Mobility Scale (CB&M), an advanced test of dynamic balance, was examined for use in individuals with knee osteoarthritis. The convergent validity, construct (known groups) validity, and test re-test reliability of the scale was assessed (Chapter 2). Convergent validity was assessed by comparing to tests measuring similar constructs, such as the Berg Balance Scale. Construct validity was assessed by comparing scoring of those with and without knee osteoarthritis. Test re-test reliability was assessed one week apart. Clinically modifiable factors associated with dynamic balancing ability were then investigated (Chapter 3). These included muscle strength, knee joint proprioception, knee joint range of motion and anticipatory postural control. Finally, a ten week dynamic balance training program, designed using findings from Chapter 2 and 3, was assessed in Chapter 4. This was a randomized controlled trial, with dynamic balancing ability and self-reported physical function measured at baseline and follow-up.Results: The CB&M was found to display moderate to strong convergent validity with other tests, strong construct validity and high test re-test reliability. Lower extremity strength, and to a lesser extent, knee range of motion were important factors associated with dynamic balancing ability. Ten weeks of training resulted in significant improvement in self-reported physical function but not in CB&M scores.Conclusion: This dissertation provides new understanding of dynamic balance assessment and treatment in those with knee osteoarthritis. These findings highlight a valid and reliable clinical outcome measure for dynamic balance, as well as provide insights into balance training program designed to improve outcomes and maintain high adherence in this population.
Mechanisms underpinning motor control of standing balance post-stroke remain unclear. Following stroke, ankle plantarflexor muscles demonstrate impairment associated with asymmetrical postural control and decreased balance. Stroke also results in increased attentional demands during challenges to standing balance. This thesis examined motor control impairment post-stroke from medial gastrocnemius motor units to the tri-muscle plantarflexor complex. Investigation of motor, kinematic and kinetic parameters of postural control during external perturbations in standing and associated levels of physiological arousal have furthered understanding of balance impairment post-stroke. Methods: Medial gastrocnemius motor units were recorded in controls (Chapter 2) and people post-stroke (Chapter 3) in standing as perturbations were sequentially applied at the pelvis under conditions of increased anteriorly-directed challenge. In both studies, motor unit firing rate was calculated during dynamic response to perturbation, and maintenance of steady state between perturbations. Joint kinematics, surface electromyography and movements of the centre of pressure were assessed. In Chapter 4, this methodology was expanded to cross-correlation analysis of electromyography activity of the three plantarflexor muscles with anterior-posterior centre of pressure during steady state. In Chapter 5, attentional demands surrounding timing of external perturbation were manipulated to investigate effects of stroke on physiological arousal and postural reactions.Results: In healthy subjects, medial gastrocnemius utilized primarily motor unit recruitment to maintain standing with a modest increase in motor unit firing rate only during the dynamic response to external perturbations. The paretic medial gastrocnemius also primarily used motor unit recruitment; however, lacked firing rate modulation during the dynamic response, albeit firing rate was related to kinematic variables of postural control. In people post-stroke, the three plantarflexors demonstrated asymmetrical motor control of postural sway between-legs but symmetry was improved under conditions of increased challenge to standing balance. Finally, knowledge of timing of perturbations did not decrease the heightened anticipatory postural strategy and level of physiological arousal exhibited post-stroke. Conclusions: This dissertation provides new understanding of motor control of standing balance post-stroke and reveals anticipatory postural strategies adopted post-stroke under conditions challenging balance. These findings implicate the importance of introducing challenge to standing balance post-stroke in the assessment and rehabilitation of postural control post-stroke.
Introduction:Knee osteoarthritis is a common and painful disease, and is one of the leading causes of disability in Canada. It is thought that one of the primary causes of disease progression is excessive knee joint loading. Thus, conservative treatments have aimed to reduce knee joint load, predominantly targeting the knee adduction moment – a valid proxy of tibial joint load distribution. Toe-in and toe-out walking are two such strategies which have proven effective in the short term at reducing the knee adduction moment, but still require longer-term assessment and a more thorough understanding of the ancillary effects at joints other than the knee prior to clinical implementation. The ankle joint in particular may be subjected to altered biomechanics during toe-in and toe-out walking.Purpose:The purpose of this thesis was to examine ankle biomechanics during toe-in and toe-out foot rotations in those with medial compartment knee osteoarthritis.Methods:Fifteen individuals with medial compartment knee osteoarthritis were recruited. In a single session, participants were instructed to walk in four conditions guided by real-time biofeedback of performance: 1) toe-in (+10°), 2) neutral (0°), 3) toe-out (-10°) and 4) toe-out (-20°). Ankle kinematics, kinetics and muscle activity were examined during over-ground walking.Results:Toe-out walking exhibited an increase (p=0.011) in peak ankle eversion compared to toe-in walking, while toe-in walking exhibited an increase in ankle inversion at heel strike (p
Introduction: Femoroacetabular impingement (FAI) is a pathomechanical process of the hip joint that has been linked to the early development of hip osteoarthritis. FAI morphology usually progresses gradually and can limit the ability of individuals to engage in sports and causes pain during activities of daily living. These impairments can lead to loss of range of motion, muscle weakness and altered walking biomechanics. Currently, surgery is the common treatment, however little is known about the effects of muscle strengthening in this population. Based on the results of similar programs in other pathologies, muscle strengthening may alleviate this muscle weakness and hip pain. Our goal was to investigate the effects of a pre-surgical hip muscle strengthening intervention on hip strength, pain and function in those with FAI.Methods: This was a within subject, pre-test – post-test intervention study examining the effects of a 10-week hip muscle strengthening program in 20 individuals (18 males) with FAI before hip surgery. Clinical outcomes including maximum isometric hip strength, hip pain and physical function were collected before and after the strengthening intervention. During the intervention, participants progressed through three phases of increasing resistance and functionality as they received a bilateral hip strengthening program consisting of 4-6 exercises per phase.Results: Maximum isometric hip strength significantly increased in abduction (p=0.008), adduction (p=0.021) and internal rotation (p=0.006) at follow-up. Flexion, extension and external rotation strength changes did not reach significance. Self-reported HOOS pain subscale scores (p
Introduction: Knee osteoarthritis (OA) is a destructive joint disease resulting from a number of factors including excessive and repetitive loading of the joints. Even though OA symptoms begin mostly in midlife, the degenerative changes of articular cartilage take place a long time before the onset, so it is important to track osteoarthritic changes at earlier phases. Radiology imaging is widely used for this purpose; however, radiology does not show minute changes that occur before onset of OA symptoms. Due to such limitations, the investigation of molecular changes is growing in today’s research. Matrix metalloproteinases (MMPs) are degenerative enzymes of connective tissue and their quantities are thought to be related to OA changes. Our goal was to investigate how MMP variance is explained by OA–related factors, mainly dynamic knee joint loading. Methods: A cross-sectional design was used to collect data on the intraarticular knee joint load, reflected by knee adduction moment (KAM), as well as serum samples in 28 participants of which half had mild to severe OA and the other half were OA-free. Laboratory-based motion analysis was used to compute the KAM, while MMP levels (MMPs- 1, 3, 13) were measured using ELISA. Multiple-regression analysis was used to investigate the explanatory role of KAM, and potential confounders like age, and OA severity in explaining MMP variance. Results: KAM impulse predicted significant variance in MMP-3 levels (R²=0.197, p=0.018). After controlling for the effect of age and severity, the explanatory role of KAM impulse was decreased (R²=0.157), still remaining statistically significant (p=0.036). The explained variance of MMP-1, 13 did not reveal statistical significance from explanatory variables. Conclusion: This research provides evidence of a positive relationship between MMP- 3 and intraarticular knee joint load, quantified by the KAM. The relationship remained significant after controlling for age and OA severity. Our findings support the notion that MMP-3 may be a candidate for OA investigations. Since MMP levels are influenced by a number of factors, it seems logical to consider the levels of other biomarkers along with them.