School of Public Health
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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
Note: Prior to July 1, 2007, the School of Public Health was named the College of Health & Human Performance.
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Item A SEQUENTIAL MIXED METHODS APPROACH TO IDENTIFYING AND UNDERSTANDING MOTIVATIONS FOR LEISURE TIME PHYSICAL ACTIVITY PARTICIPATION AMONG AMPUTEES(2022) Olsen, Sara H; Howard, Donna E; Public and Community Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Physical inactivity contributes to increased risk for hypertension, coronary heart disease, diabetes, various cancers, and depression. Research shows small increases in leisure time physical activity (LTPA) level among the least active populations result in larger improvements in overall health than any increase in LTPA among more active populations. People with disabilities (PwD) are less likely to meet physical activity (PA) guideline recommendations than their counterparts in the general population (39.2% vs 53.8%). People with mobility disabilities, such as those with amputations, are less active than those with other disabilities. Amputees, however, are largely absent from physical activity-related and disability-related research. One step toward improving LTPA participation among amputees is understanding motivations to be active and the experiences influencing those motivations. Using Self-Determination Theory (SDT) as a framework, this dissertation employed a sequential explanatory mixed methods approach to integrate fitness app intervention data with interpretative phenomenological analysis (IPA) findings. The quantitative component evaluated an app-based intervention with a waitlist control experimental design. Outcomes of motivations and PA level (Aim 1) were evaluated using linear mixed effect models. Amotivation, extrinsic motivation, and intrinsic motivation were evaluated as separate outcomes. Changes in amotivation and total activity level were significant during the intervention; there were no significant changes in extrinsic or intrinsic motivation. Amotivation (complete disinterest in LTPA) increased in both groups, but the increase was greater in the waitlist control group, suggesting use of the app staved off amotivation even though it did not contribute to increases in intrinsic motivation. Total activity increased in the waitlist control group only. Moderation was tested using SDT constructs of general causality orientation, a personality trait that represents a person’s belief about behavioral change and reasons to change (Aim 2). Amotivation is moderated by general causality orientation. Results from intervention analyses, including attrition analysis, were used to develop interview guides and participant inclusion criteria for the qualitative phase. In-depth interviews with amputees (Aim 3) explored motivations to be active and embodied PA experiences. IPA resulted in the development of six superordinate themes. Data from both the intervention and interviews were integrated to develop a deeper understanding of amputees’ experiences with motivations to be active (Aim 4). Participants identified barriers and facilitators to PA engagement that were unrelated to and unaffected by motivation to be active. These experiences disrupted the association between motivation and participation which added context to the intervention findings in which changes in intrinsic motivation over time did not parallel changes in PA over the same intervention period. Public health implications and suggestions for future research are discussed.Item Kinetics in Individuals with Unilateral Transtibial Amputations Using Running-Specific Prostheses(2012) Baum, Brian Svercauski; Shim, Jae Kun; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Improvements in rehabilitation and prosthetic design are needed to help promote activities such as running that increase physical activity levels of individuals with lower extremity amputation (ILEA). However, effectively developing these improvements requires a detailed understanding of prosthetic and ILEA running biomechanics. Running-specific prostheses (RSPs) have been developed to improve running performance for ILEA runners, but altered running kinetics may still be necessary to accommodate for the loss of musculoskeletal function caused by lower extremity amputation. The few studies investigating ILEA running with RSPs focus on maximal performance, but our understanding of how ILEA using RSPs modulate kinetics to run at submaximal velocities remains limited. The purpose of this study was to characterize changes in kinetics and mechanical energy across a range of running velocities in ILEA wearing RSPs. This dissertation investigated six specific aims through six corresponding experiments that improve our knowledge of mechanical and anthropometric properties of RSPs and the kinetic profiles of ILEA running at submaximal velocities. Four common RSP designs were tested for mechanical and anthropometric properties. ILEA with unilateral transtibial amputations who wear RSPs and an able-bodied control group participated in the running experiments. Mechanical and anthropometric results indicated that RSP marker placement had little effect on joint kinetic estimations proximal to the prostheses, and trifilar pendulums can measure moments of inertia with <1% error. The running experiments provided the first 3D kinetic descriptions of ILEA running. The prosthetic limb typically generated lower peak kinetic parameters and 50% lower total mechanical work than the intact and control limbs, indicating a greater reliance on the intact limb. To counter the prosthetic limb deficiencies, ILEA increased stride frequencies compared to control subjects. Additionally, the prosthetic limb demonstrated prolonged periods of anterior ground reaction force to increase propulsive impulse and prolonged hip stance phase extension moments that generated increased hip concentric work. The data indicated that ILEA wearing RSPs run differently than able-bodied runners and use several adaptive mechanisms to run at the same velocity and to increase running velocity. These mechanisms are discussed and future directions of research are suggested.