Objectives: This study aimed to investigate the risks and impacts associated with fractures, osteoporosis, frailty, physical function, and dementia in older adults in community and LTC setting. The study aims to identify important factors influencing these health issues and identify strategies for improving management and outcomes. Methods: The research integrates data from three primary sources: Project 1 (ICES Data Repository): Healthcare utilization and administrative databases were linked using unique, encoded identifiers from the ICES Data Repository to estimate hip fractures and osteoporosis management among adults aged 66 and older from April 1, 2014, to March 31, 2018. Osteoporosis management was assessed through pharmacotherapy records. Sex-specific and age-standardized rates were compared based on pre-fracture residency and discharge location (e.g., LTC to LTC, community to LTC, or community to community). Fracture risk was determined using the Fracture Risk Scale (FRS). Project 2 (Canadian Longitudinal Study on Aging - CLSA): Participants aged 45 to 85 years who completed both the baseline and three-year follow-up assessments were included. Outcomes examined include frailty (Fried Frailty Phenotype), and physical function limitations. MSK conditions were self-reported diagnosis by a health care professional and included rheumatoid arthritis (RA), osteoarthritis (OA), low-back pain, osteoporosis, and related fractures. Project 3: The review employed Arksey and O'Malley's framework, guided by Joanna Briggs Institute methodology and PRISMA-ScR guidelines. A comprehensive search strategy was implemented across MEDLINE, EMBASE, CINAHL, and grey literature. Independent reviewers used Covidence software for study selection and data extraction. A narrative synthesis was conducted to summarize findings, identify patterns, and highlight gaps in the literature. Findings: We found increasing hip fracture rates and low osteoporosis treatment in LTC settings, highlighting to the need for improved screening and management of osteoporosis treatment in LTC. In community, hip fracture rates decreased. We found that older adults with musculoskeletal (MSK) conditions at baseline were more likely to experience frailty at the three-year follow-up compared to those without MSK conditions. However, this association was not significant in the unadjusted analysis. Individuals with cognitive decline experience worse outcomes following hip fractures, underscoring the need for integrated care addressing both physical and cognitive health. Conclusion: Hip fractures, frailty, physical function decline, and cognitive decline are prevalent and interrelated issues among older adults aged 65 and older. These findings underscore the need for improved screening and integrated care strategies to enhance management and prevention of these complex health challenges. / Thesis / Doctor of Philosophy (PhD) / Aging is associated with increased risks of osteoporosis, fractures, frailty, physical function decline, and dementia, particularly for older adults in long-term care (LTC). This study explores these health challenges by analyzing data from three key sources: ICES, the Canadian Longitudinal Study on Aging (CLSA), and a scoping review of patient-important outcomes following a hip fracture in older adults with cognitive impairment or dementia. First, we found increasing hip fracture rates in LTC and among older adults living in community at time of fracture and transferred to LTC post fracture. Osteoporosis treatment was low among high fracture risk LTC residents. Second, we found that older adults with baseline musculoskeletal (MSK) conditions (osteoporosis, fractures, osteoarthritis (OA), rheumatoid arthritis, and back pain) were more likely to become frail and have physical function limitation over three years compared to those without MSK conditions. However, after adjusting for covariates, these associations were no longer significant. Among the individual MSK conditions, we found older adults with only OA and osteoporosis-related fractures to be significantly associated with physical functional limitations. Lastly, we found that following a hip fracture, older adults with cognitive impairment or dementia have poorer functional outcomes, reduced quality of life, higher hospitalization and mortality rates, and are significantly more likely to be institutionalized compared to older adults without cognitive impairment or dementia, highlighting the need for integrated care that addresses both physical and cognitive health

In this dissertation, the design and development of a hybrid robotic system that simulates dynamic biomechanical tasks of the lower extremity with emphasis on knee and hip joints are presented. The hybrid system utilizes a mechanical hip and a cadaveric knee/ankle component and can accelerate the whole complex towards the ground. This system is used to simulate complex athletic movements such as landing from a jump at various anatomical orientations of the lower extremity with muscle action. The dynamic response of the lower extremity is monitored and analyzed during impulsive contact between the ground and the cadaveric leg. The cadaveric knee is instrumented to measure strain of the Anterior Cruciate Ligament (ACL) during simulated high impact sports activities. The mechanical hip allows various kinematics of the hip including flexion as well as abduction. In addition to the flexion and abduction of the mechanical hip, the controlled flexion and extension of the cadaveric knee allows for simulation of complex tasks such as landing from a jump. A large number of tests were performed at various anatomical positions utilizing this device to simulate landing from a jump. ACL strain was measured during these tasks using a Differential Variance Resistance Transducer (DVRT). Ground Reaction Force and muscle forces were measured and monitored using AmCell load cells recorded using the LabView software. one-inch and 6-inch jump landing heights were used for all the simulations. The tests were performed at differing angles of hip flexion (0°, 30°, 45°, 60°) and at two different ankle positions. Plantar flexion and flat-footed landing conditions were simulated and compared in all degrees of hip flexion. These tests were repeated with and without hip abduction in order to study the effects of these landing positions on ACL strain. Hip flexion was found to effect ACL strain: as angle of hip flexion increases, ACL strain decreases. This occurred in both abducted and non-abducted hip positions. Ankle landing position had an effect only in small drop heights, while hip abduction had an effect in large drops. Future tests must be completed to further study these effects. These studies showed that the robotic system can simulate dynamic tasks, apply muscle forces, and move the cadaveric tissue in three dimensional biomechanical positions. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

Although people can typically maintain balance on moving trains, or press the appropriate button on an elevator with little conscious effort, the apparent ease of these sensorimotor tasks is courtesy of neural mechanisms that continuously interpret many sensory input signals to activate muscles throughout the body. The overall hypothesis of this work is that motor behaviors emerge from the interacting constraints and features of the nervous and musculoskeletal systems. The nervous system may simplify the control problem by recruiting muscles in groups called muscle synergies rather than individually. Because muscles cannot be recruited individually, muscle synergies may represent a neural constraint on behavior. However, the constraints of the musculoskeletal system and environment may also contribute to determining motor behaviors, and so must be considered in order to identify and interpret muscle synergies. Here, I integrated techniques from musculoskeletal modeling, control systems engineering, and data analysis to identify neural and biomechanical constraints that determine the muscle activity and ground reaction forces during the automatic postural response (APR) in cats. First, I quantified the musculoskeletal constraints on force production during postural tasks in a detailed, 3D musculoskeletal model of the cat hindlimb. I demonstrated that biomechanical constraints on force production in the isolated hindlimb do not uniquely determine the characteristic patterns of force activity observed during the APR. However, when I constrained the muscles in the model to activate in a few muscle synergies based on experimental data, the force production capability drastically changed, exhibiting a characteristic rotation with the limb axis as the limb posture was varied that closely matched experimental data. Finally, after extending the musculoskeletal model to be quadrupedal, I simulated the optimal feedforward control of individual muscles or muscle synergies to regulate the center of mass (CoM) during the postural task. I demonstrated that both muscle synergy control and optimal muscle control reproduced the characteristic force patterns observed during postural tasks. These results are consistent with the hypothesis that the nervous system may use a low-dimension control scheme based on muscle synergies to approximate the optimal motor solution for the postural task given the constraints of the musculoskeletal system. One primary contribution of this work was to demonstrate that the influences of biomechanical mechanisms in determining motor behaviors may be unclear in reduced models, a factor that may need to be considered in other studies of motor control. The biomechanical constraints on force production in the isolated hindlimb did not predict the stereotypical forces observed during the APR unless a muscle synergy organization was imposed, suggesting that neural constraints were critical in resolving musculoskeletal redundancy during the postural task. However, when the model was extended to represent the quadrupedal system in the context of the task, the optimal control of the musculoskeletal system predicted experimental force patterns in the absence of neural constraints. A second primary contribution of this work was to test predictions concerning muscle synergies developed in theoretical neuromechanical models in the context of a natural behavior, suggesting that these concepts may be generally useful for understanding motor control. It has previously been shown in abstract neuromechanical models that low-dimension motor solutions such as muscle synergies can emerge from the optimal control of individual muscles. This work demonstrates for the first time that low-dimension motor solutions can emerge from optimal muscle control in the context of a natural behavior and a realistic musculoskeletal model. This work also represents the first explicit comparison of muscle synergy control and optimal muscle control during a natural behavior. It demonstrates that an explicit low-dimension control scheme based on muscle synergies is competent for performance of the postural task across biomechanical conditions, and in fact, may approximate the motor solution predicted by optimal muscle control. This work advances our understanding how the constraints and features of the nervous and musculoskeletal systems interact to produce motor behaviors. In the future, this understanding may inform improved clinical interventions, prosthetic applications, and the general design of distributed, hierarchal systems.

Thesis (Ph. D.)--University of Missouri--Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 63-74). Also available on the Internet.

Thesis (M.S.) -- Mississippi State University. Department of Industrial Engineering. / Title from title screen. Includes bibliographical references.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2009. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 84-94).

Thesis (Ph.D.)--Memorial University of Newfoundland, Faculty of Medicine, 2001. / Typescript. Bibliography: leaves 178-200.

Thesis (Ph. D.)--West Virginia University, 2010. / Title from document title page. Document formatted into pages; contains x, 178 p. : ill. Includes abstract. Includes bibliographical references.