Theses and Dissertations at Montana State University (MSU)

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    Design, fabrication, and validation of a portable perturbation treadmill for balance recovery research
    (Montana State University - Bozeman, College of Engineering, 2022) Knutson, Robert George; Chairperson, Graduate Committee: Corey Pew
    Trips and falls are a major concern for older adults. The resulting injury and loss of mobility can have a significant impact on quality of life. An emerging field of study, known as Perturbation Training, has been shown to reduce injury rates associated with trips and falls in older adults. In a typical training session, the user stands or walks on a treadmill and is subject to sudden, unexpected accelerations, simulating a trip or slip, in a safe environment. This training aims to improve the user's ability to maintain and recover balance in situations that can often lead to falls. Treadmills traditionally used for Perturbation Training are large instrumented devices that are rigidly bolted to the floor. This presents a problem for older adults with limited mobility or those who live far away from Perturbation Training facilities. A portable treadmill would be able to serve a larger portion of the at-risk population then current methods have allowed. We developed a portable, low-cost perturbation treadmill capable of high-intensity training. The system can perform trip and slip perturbations from a stationary or walking state. It features a tandem belt configuration, a small gap between belts, and individual belt control. The belt speed is digitally controlled, dictated by a custom human-machine-interface and software suite, which allows operators with no programming experience to control the device. When connected to a 240-volt power supply, the maximum belt speed is approximately 3.6 m/s. The treadmill was designed to accommodate a user of up to 118 kg and provide a maximum acceleration of 12 m/s 2 under full load. The treadmill weighs approximately 180 kg and can be moved like a wheelbarrow, with handles in the back and wheels in the front. The design has been validated and was used in multiple locations in a clinical trial.
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    Effects of reactive balance training on joint health
    (Montana State University - Bozeman, College of Education, Health & Human Development, 2022) Peart, Dakota Paul; Chairperson, Graduate Committee: David Graham
    Falls are a major cause of mortality and morbidity among older adults. One of the major risk factors of falls is impaired neuromotor function, which can be addressed through conventional exercise programs. While beneficial for many aspects of health, conventional training does not appear to greatly reduce the incidence of falls. More recently, reactive balance training (RBT) has emerged as a task-specific exercise that is highly effective and efficient at reducing subsequent fall rates. However, little is known about the tissue-level effects that this high-impact exercise may have on the joints of participants. Overtraining by performing RBT at excessive volumes or intensities could feasibly cause damage and degradation of joint-related tissues, potentially leading to discomfort and even post-traumatic osteoarthritis. Such processes are driven by mechanisms featuring general and tissue specific signaling molecules, and also yield tissue-specific breakdown products. To explore the possibility of joint damage resulting from reactive balance training, healthy middle-aged adults performed varying amounts of RBT, and the resulting signaling responses were observed. It was found that RBT does induce a prominent biochemical response, and the nature and magnitude of the response appears to be influenced by the volume and intensity of training performed.
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    Methodological considerations and clinical utility of analyzing transient behavior in quiet stance postural control
    (Montana State University - Bozeman, College of Engineering, 2020) Reed, Cody Aaron; Chairperson, Graduate Committee: Scott Monfort; Ajit M.W. Chaudhari, Lise C. Worthen-Chaudhari, Kimberly E. Bigelow and Scott M. Monfort were co-authors of the article, 'A new perspective on transient characteristics of quiet stance postural control' in the journal 'PLOS ONE' which is contained within this thesis.; Scott M. Monfort were co-authors of the article, 'Influence of a cognitive perturbation on transient characteristics of quiet stance postural control' submitted to the journal 'Gait & posture' which is contained within this thesis.
    Postural control has been widely studied to provide insight into various health concerns. Traditionally, postural control is assessed using whole-trial analysis techniques that measure center of pressure parameters as a singular estimate for an entire trial. These whole-trial estimates may be more reliable for longer duration trials. However, longer trials and whole-trial analyses mask transient (i.e., a destabilized period followed by a transition to a more stable, quasi-steady state level) responses within center of pressure data. By only using whole-trial estimates, we may be missing out on unique information that is contained within this understudied aspect of postural control. Therefore, four experiments were conducted to better understand the clinical utility of evaluating transient postural control behavior. The first experiment tested whether transient, epoch-based characteristics of center of pressure parameters provided unique information compared to traditional whole-trial estimate approaches. The second experiment evaluated participants in eyes open and closed conditions to test whether transient behavior was a sensory reweighting response to eye closure. The third experiment tested whether transient characteristics of postural control could distinguish between younger and older adults. Based on the results of the first three experiments, a fourth experiment was conducted to investigate the influence of cognitive perturbations on transient characteristics of postural control. Negligible correlations were found between transient characteristic and whole-trial estimates, indicating that unique information is contained in transient measures of postural control. Although transient behavior was exaggerated during eyes closed stance, transient behavior still existed during eyes open stance. In addition, select transient characteristics distinguished between young and older adult groups, supporting the clinical relevance of transient measures. Lastly, cognitive perturbations influenced transient postural behavior, supporting the use of transient measures for analyzing dual-task scenarios. Overall, our results support the use of epoch-based estimates to characterize transient postural behavior as a complementary assessment to traditional whole-trial analyses. Our results also indicate the need to carefully consider how postural control trials are analyzed and initiated. Moving forward, further evaluation of transient characteristics of postural control is warranted to determine their relationship to health outcomes such as falls.
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    Habituation during repeated exposure to balance recovery from a forward loss of balance in younger adults
    (Montana State University - Bozeman, College of Education, Health & Human Development, 2021) Whitten, Justin Mark Moeller; Chairperson, Graduate Committee: David Graham; Dawn S. Tarabochia, John G. Siefert and David F. Graham were co-authors of the article, 'Changes in margin of stability during repeated exposure to forward loss of balance in young adults' submitted to the journal 'Journal of biomechanics' which is contained within this thesis.; Dawn S. Tarabochia, John G. Siefert and David F. Graham were co-authors of the article, 'Changes in muscular effort during repeated exposure to forward loss of balance in young adults' submitted to the journal 'Journal of biomechanics' which is contained within this thesis.
    The purpose of this study was to begin to develop within session volume parameters for perturbation-based balance training by determining the minimum number of exposures needed for participants to habituate to balance recovery from a substantial perturbation. Two young adult participants were exposed to 15 substantial perturbations induced via release from a static forward lean. All participants were instructed to attempt to recover balance by taking a single rapid step. A scalable anatomical model consisting of 36 degrees-of-freedom and 94 muscle actuators was used to compute kinematics and joint moments from motion capture and force plate data. Margin of stability was calculated at heel strike and maximum knee joint flexion to quantify balance recovery performance. Balance recovery trials were divided in to three blocks (early, middle, and late) with 5 trials in each block and static optimization was used to compute estimates of the mean and peak force generated by key muscle groups during recovery for each block. Participant margin of stability declined rapidly during early balance recovery trials and plateaued between trials 5-8. Hip abductor forces remained relatively consistent across trials while the force produced by the Vastus Femoris group decreased during the mid and late trial blocks. Mean force produced by the Soleus during balance recovery decreased across trial blocks. In contrast, the peak force and impulse generated by the Soleus increased across trial blocks. We interpret these data to reflect an adaptation in balance recovery coordination strategy, which appears to occur sometime between the early and middle trial blocks and stems from young participants desire to minimize the effort associated with successful recovery of balance. These results further suggest participants became habituated to balance recovery after exposure to 5-8 substantial perturbations.
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