The variability present in human locomotion has been an increasing area of study. Originally thought to be associated with pathology, recent evidence suggests that coordination variability may offer an adaptive mechanism. The purpose of this series of investigations was to describe the relation between stride characteristic variability and joint coordination variability during running among persons with and without patellofemoral pain. Second, the role of pain in the observed changes in movement variability among persons with patellofemoral pain was investigated. Finally, the presence of gait asymmetries and variability present between the lower extremities of persons with patellofemoral pain was addressed. Three-dimensional kinematic data were collected from bilateral lower extremities of eight subjects with unilateral patellofemoral pain, as well as eight non-impaired subjects. All subjects ran on a treadmill at fixed (2.68-m·s −1) and preferred speeds during four collection sessions, while reporting perceived pain. The initial session involved subjects running while experiencing pain, with the final three collections being reduced pain sessions. The patellofemoral subjects displayed increased stride length variability of both limbs during running at preferred speed compared to non-impaired subjects. Intralimb joint coordination variability across the entire stride was consistent between groups. Further analysis, however, revealed that during preferred speed running, the patellofemoral pain group displayed reduced variability in the thigh rotation:leg rotation coupling of the injured limb at heel-strike compared to the non-impaired group. A direct relation between pain and stride length variability was present, as both pain and stride length variability decreased simultaneously among subjects with patellofemoral pain. In addition, the level of variability among the thigh rotation:leg rotation coupling at heel-strike was observed to increase following pain reduction. Joint coordination asymmetry was consistent between subjects with and without patellofemoral pain. However, the patellofemoral pain group displayed greater variability in interlimb knee rotation. Additionally, the transverse and coronal planes revealed greater levels of asymmetry and variability than the sagittal plane for both groups, suggesting an adaptive role. While patellofemoral pain impacted stride length variability, it appeared to alter only the variability of transverse plane joint coordination. Future analyses may involve a task that elicits a greater pain response.

The aim of this dissertation was to examine the use of accelerometers to measure physical activity (PA) in children with and without disabilities and address some of the current methodological issues involved with their use. Study I compared the activity level of children with Down syndrome (DS), children with intellectual disabilities without DS, and children without disability. Subjects wore ActiGraph accelerometers for seven days. There were no significant differences in PA level among the three groups of children as measured by mean ActiGraph counts per day. No difference was found between groups in the amount of time spent daily at different activity intensities. This study was the first to objectively assess PA in children with disabilities using accelerometers and demonstrated that accelerometers are feasible for PA measurement in children with cognitive impairments. Study II and Study III examined methodology issues with accelerometer data interpretation. Study II compared the accuracy of several count cut-point values used to define activity intensity ranges. Fifty-one children wore an ActiGraph at the hip while performing locomotor or free-play activities. Actual MET level, measured via indirect calorimetry, was compared to the predicted MET level from the different ActiGraph cut-points. Percent agreement between actual and estimated intensity level ranged from five to 100 percent between the different cut-point thresholds. These results quantified the differences in intensity classification seen with the different cut-points and demonstrated ActiGraph results extrapolated from different cut-points cannot be compared. Study III assessed the use of the count coefficient of variation (CV) to distinguish locomotor from non-locomotor activities in children. The accuracy of energy expenditure (EE) prediction using a dual-equation method based on count CV was compared to the accuracy of using a single prediction equation. The count CV distinguished between locomotor and non-locomotor activities quite well. Despite this, using the activity specific dual-equation method to predict EE did not improve accuracy compared to single prediction equations. No prediction equation tested adequately estimated EE from count values in this study. Due to the variable nature of movement and play in children, and metabolic and size differences, predicting EE from hip-mounted accelerometers is not ideal.

Many factors contribute to a successful rehabilitation outcome, including medical, technological, psychological, and environmental variables. The current study was an attempt to assess the role played by the psychological and environmental variables in rehabilitation outcome. Among the possible psychological factors that patients bring to the rehabilitation process are personality traits, self-motivation, and mental health functioning such as depression. Some of the environmental factors include the way in which patients perceive the atmosphere of the rehabilitation hospital in terms of support and expectations and the support of the patients' family after discharge from the hospital. The role each of these factors plays in rehabilitation outcome was investigated. A sample of 60 patients who had been admitted to a rehabilitation hospital following a stroke or orthopedic procedure completed psychological and environmental measures at admission, discharge, and three month followup. In addition, the participants' level of functional independence was assessed by hospital staff at each of these times. Statistical analyses were performed to determine the impact of the psychological and environmental variables on rehabilitation outcome. Measures of rehabilitation outcome included where patients were discharged, their level of functional independence at discharge and followup, and the change in their levels of functional independence from admission to discharge. Results supported the idea that psychological variables play a role in rehabilitation outcome. Those participants who were discharged home tended to have higher motivation scores at admission than those who were discharged to a nursing home. In addition, life satisfaction and depression scores were significant factors in predicting participants' level of functional independence at discharge. Results of the analyses of the personality and environmental variables were not significant. The results of the study suggest that one's level of self-motivation upon admission to a rehabilitation hospital may influence whether he or she is discharged home or to a skilled nursing facility. The relation between motivation and discharge location is not entirely clear, thus more research is required. Future researchers may wish to investigate the perception of patients' motivation by the hospital staff to determine whether this perception plays a role in discharge planning. Others may focus on whether interventions to increase patients' motivation can produce more positive rehabilitation outcomes. In any case, research on the role of self-motivation in rehabilitation appears to be a worthwhile endeavor.

This research involved systematic investigation of mechanisms which underlie neural adaptations to training. Observations were made of human motor unit control properties. Considerable evidence suggests impairment of neural, neuromuscular, and musculoskeletal function with aging, thus the process of adaptation to training was compared between healthy young and older adults. Experiment I examined whether early strength gains result from changes in central drive, defined as maximal motor unit discharge rate (MUDR). MUDR was obtained at four points over a six week strength training program. Both young and older adults demonstrated significantly increased maximal MUDR on Day 2 which returned to baseline by the end of the training period. Despite significantly lower maximal MUDR at baseline, older adults produced central drive comparable to young individuals on Days 2 and 14. Experiment II addressed the role of variability of sustained motor unit discharge (MUV) and its effect on the generation of muscular force. MUV was significantly redistributed with aging, punctuating the frequency content between 0-4 Hz. With training, only young individuals demonstrated significant adaptation, reducing the 0-4 Hz contribution and increasing the 5-8 Hz and 9-12 Hz contributions to MUV. These training-related adaptations suggest the role of supraspinal influences in damping oscillatory activity of musculoskeletal dynamics. Experiment III examined the range over which motor unit discharge is modulated for adaptation with strength training. MUDR range was similar between young and older individuals when examined with respect to absolute force differences but was significantly lower in older adults when examined with respect to relative effort. Importantly, significant adaptations to training were not evidenced in MUDR range by young adults, while a transient increase, paralleling the pattern of change in maximal MUDR, was demonstrated by elders. Experiment IV examined adaptation and modulation of antagonist motoneuron excitability. Hoffman reflex (H-reflex) responses were obtained from the soleus muscle while a concurrent force modulation task was performed with tibialis anterior. Over six weeks subjects trained to improve control of dorsiflexion force. H-reflex amplitudes were significantly smaller in older adults suggesting alteration in motoneuron pool activation due, potentially, to remodeling of spinal pathways in favor of antagonist muscle co-contraction.

The multidimensional nature of fibromyalgia syndrome (FMS) requires heath care practitioners to adopt a biopsychosocial approach to care in order to select appropriate individualized interventions for patients. The philosophical perspective of the practitioner and the level of frustration held by the practitioner towards patients with FMS are believed to contribute to the adoption of a biopsychosocial approach to care. The purpose of this study was to explore these specific practitioner characteristics and their relationship to the adoption of a psychosocial approach to care for patients with FMS. Specifically, the philosophical perspective of the practitioner and the frustration level of practitioners towards patients with FMS were explored as predictors to attitudes and beliefs about psychosocial care for patients with FMS. The sample for this descriptive correlational study consisted of 134 health care practitioners who care for patients with FMS. The Organicism-Mechanism Paradigm Inventory (OMPI) used to measure practitioner philosophical perspective and the Difficult Doctor Patient Relationship Scale (DDPRQ) used to measure frustration level in relation to attitudes and beliefs about psychosocial care for patients with fibromyalgia, measured by the Physician Belief Scale (PBS). Nurse practitioners and physicians differed significantly on philosophical perspective, frustration levels, and attitudes and beliefs about psychosocial care for patients with FMS. Philosophical perspective was a predictor of attitudes and beliefs towards psychosocial care for patients with FMS in a single predictor model. The same was true for frustration levels towards patients with FMS. However, only frustration level was predictive of attitudes and beliefs about psychosocial care when both variables of interest were entered in to a regression model. These findings have implications for care of patients with FMS. Practitioners who participate in educational interventions aimed at understanding and enhancing communication skills with patients seen as frustrating to the patient-practitioner relationship may improve care by utilization of a biopsychosocial approach.

It has been reported that female athletes are 4 to 6 times more likely to sustain a non-contact anterior cruciate ligament injury than their male counterparts. The purpose of this series of investigations was to investigate the influence of gender on anterior knee laxity; lower extremity joint kinematics and kinetics; and lower extremity coupling variability. For the first investigation anterior knee laxity data were collected from 12 male and 12 female athletes pre- and post-exercise across multiple data collection sessions. In addition, serum estrogen and progesterone was measured across data collections for the female subjects. For the second and third investigations three-dimensional kinematic and kinetic data were collected from the hip and knee joints of 12 female and 12 male collegiate soccer players while performing an unanticipated cutting maneuver. The first investigation revealed that there was no relationship between anterior knee laxity and acute changes in circulating estrogen and progesterone. However, females exhibited greater laxity than did males both pre- and post-exercise. Males and females demonstrated equivalent increases in laxity associated with exercise. These increases in laxity following exercise resulted in the females exhibiting more laxity than the males ever reached. This increased laxity may suggest that the female athlete does not obtain equivalent stabilization from their knee ligaments as their male counterparts. The second investigation revealed that male and female collegiate soccer players demonstrated similar hip and knee joint kinematics and kinetics while performing an unanticipated cutting maneuver. This lack of differences suggests that the collegiate athlete's acquired training and exposure to sport results in more similar mechanics between genders. In the final experiment females exhibited decreased variability in the thigh/leg rotation coupling as well as in the hip rotation/knee abduction-adduction coupling during the cutting maneuver. If females are exhibiting inflexible coordination patterns during high-level competition as compared to males, they may have decreased ability to adapt to the frequent external perturbations incurred during play. These external perturbations applied to an inflexible system may result in acute injury or may lead to repetitive micro-trauma to the ligament resulting in a predisposition to non-contact ACL injury.

Cardiovascular disease is the leading cause of death in America today. The potential onset of cardiovascular disease in the fourth decade for men and fifth decade for women, underscores the scope of the health problem, as the population grows older. Twenty-three percent of men and thirty percent of women who survive a myocardial infarction will have a recurrence within six months. Patients with coronary artery bypass grafts are more susceptible to progressive stenosis from atherosclerosis than native vessels. Secondary prevention through physical activity is recommended by the AHA to reduce the occurrence of these events, requiring expensive re-intervention. However, less than one half of those eligible for cardiac rehabilitation enroll. The purpose of this study is to examine whether cardiac rehabilitation or home-walking with or without nurse telephone support will affect cardiac recovery. A convenience sample of sixty-three cardiac patients self-selected a cardiac rehabilitation (comparison) program in this quasi-experimental research design. One hundred twenty-six surgical cardiac patients were randomized to a home-walking or control group. MANCOVA tests on health status, self-efficacy, and diastolic blood pressure revealed significant differences for the main effect of group on health status, self-efficacy, and diastolic blood pressure (F = 3.980, 16,647, 6.562, p = .020, .000, .011), while controlling for pre-self-efficacy, medical diagnosis, and age. Post hoc tests showed no significant difference between the cardiac rehabilitation and home-walking groups on health status (p = .485) and self-efficacy scales (p = .285). No significant difference was found between the home-walking and control groups on health status ( p = .241). A significant difference was found between the cardiac rehabilitation and control groups on all three dependent variables, respectively (p = .016, .000, .000). The home-walking group revealed a significant difference on self-efficacy from the control group (p = .000). Additional findings include significant differences between home-walking and control groups on physical function (F = 7.3354, p = .0009) and mental health (F = 4.3659, p = .0140). The findings indicate that a home-walking program could be a comparable alternative to a cardiac rehabilitation group by improving self-efficacy and health status and lowering blood pressure.

The purpose of this series of investigations was to determine how custom foot orthotic intervention influences the lower extremity dynamics and intra-limb coordination in healthy and injured female runners. For the first investigation, dynamic data were collected from 12 healthy female runners (Control group) and 12 female runners with a recent history of overuse knee running injury (Treatment group). Results revealed that the influence of CFO intervention on lower extremity appears to occur with short-term intervention. The intervention produced a similar response in both groups. The knee kinematics were not influenced by the intervention however there were changes observed in knee kinetics. For the second investigation, dynamic data were collected during overground running trials in Treatment group from Study One who had completed 6 weeks of orthotic therapy. Data were collected with the subjects running with (CFO condition) and without (Shod condition) foot orthoses in three running shoes with varying midsole composition. Results revealed that the only kinematic variable influenced by running shoe midsole durometer was maximum rearfoot eversion velocity. However, CFO intervention in the footwear led to significant decreases in rearfoot kinematic variables, tibial internal rotation and internal ankle inversion moments. In addition, it was revealed that when a CFO intervention is added to a shoe of lesser density, the dynamics exhibited by the runner are similar to when wearing a shoe of greater density. For the third investigation, kinematic data were collected from 9 healthy female runners (Control group) and 9 female runners with a recent history of overuse knee running injury (Treatment group). Both groups performed a 30-minute treadmill run and relative motion plots were created for the intra-limb couplings. Results revealed that CFO intervention helped to maintain variability during the early stance phase throughout the course of the run in the injured runners. In the Treatment group, the TibTP/CalFP and KnTP/RFFP coordination variability during the early stance phase significantly decreased throughout the course of the 30-minute run for the Shod condition. While wearing the CFO condition the variability went unchanged and better resembled patterns exhibited by the Control group.

Abstract The focus of this thesis is stress in rehabilitation professionals. Within the thesis, burnout encompasses compassion fatigue and moral stress. Therefore, burnout is the emotional and ethical fatigue which is produced through organizational and clinical expectations present when working with individuals who live with disabilities. This thesis argues that current rehabilitation service delivery models exacerbate burnout through their neglect of emotional and ethical needs in professionals. The goal of this thesis is to develop an alternative model of service delivery which addresses burnout in rehabilitation professionals. The thesis answers the following question. How does Jean Vanier's thinking about relationships between individuals, living with and without disabilities, contribute to the field of rehabilitation therapy and, more specifically, to reducing stress currently experienced by rehabilitation professionals? To answer this question and meet the thesis goal, the research is situated within a constructivist paradigm and uses a single, interpretive case study design. This research has produced the transformational model of service delivery. This model states rehabilitation is a transformational process. Whereas traditional rehabilitation views the client as the focus of the change process, the transformational model states both the client and the professional benefit from their participation in a transformational change process. The change process is directed at the personal identity of both client and professional and is characterized by increased awareness and acceptance of key aspects within self and other. Whereas in more traditional rehabilitation models, creating the relational conditions necessary for change is the professional's responsibility, within the transformational rehabilitation model, both client and professional contribute to the relationship which is characterized by commitment, co-operation and compassion. In addition, client and professional experience the outcome of transformation, maturity. A mature person is defined by his/her capacity for agency and authenticity. This thesis argues that Jean Vanier is relevant to rehabilitation professionals. The articulation of an alternative model of service delivery, based on Vanier's thinking about relationships between individuals living with and without disabilities, makes a significant contribution to reducing stress in rehabilitation professionals. / Thesis (Ph.D, Rehabilitation Science) -- Queen's University, 2007-10-05 08:51:06.833

The purpose of this dissertation was to investigate, in vivo, the effect of low back pain status on lumbo-sacral (L5S1) joint reaction force and moment profiles, and also on pelvis-trunk coordination during locomotion. We studied three groups of runners: runners with low to moderate LBP (LBP), runners who had recovered from a single bout of acute LBP (RES), and runners who never had LBP (CTRL). We developed an inverse dynamics model to investigate L5S1 mechanics. Results indicated that L5S1 reaction forces increased as stride length increased (p<0.024) in healthy runners, as did peak sagittal L5S1 moments (p=0.078). Subsequently, we used this model to examine L5S1 differences between our three experimental groups at their preferred running speed and at 3.8 m/s. While differences were observed between speeds for many L5S1 variables, and between groups for peak vertical GRF, no differences were found between groups for lumbar angle ROM, peak L5S1 joint reaction force, or L5S1 joint moment. In a further study, pelvis and trunk range of motion (ROM), relative phase coordination (CRP) and coordination variability (CRPvar) were compared between our groups over a range of locomotor speeds. We found increased pelvis-trunk CRP in the frontal plane for the LBP group as compared to the CTRL group during walking (p=0.029). During running, we observed increased pelvis axial ROM for the LBP group as compared to CTRL (p=0.010), and increased CRP for CTRL as compared to both RES (p=0.021) and LBP group (p=0.025), and increased CRPvar for CTRL as compared to LBP group (p=0.019). Findings from the second and third studies demonstrated differences between clinical groups despite the relative low levels of disability (mean Modified Oswestry Disability Questionnaire score = 7.9±6.2%), and suggest that mechanical and coordinative differences exist between those with and without LBP. Further, our RES group demonstrated characteristics common to both extreme groups (CTRL and LBP), supporting previous literature regarding residual performance effects. Our findings further suggest that the RES group represented a transition stage between the CTRL and LBP groups.