Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
Browse
10 results
Search Results
Item The effects of angled insoles on short radius flat-track running mechanics(Montana State University - Bozeman, College of Engineering, 2023) Bianchini, Christopher David; Chairperson, Graduate Committee: Corey PewWhile indoor track allows athletes to compete during the winter period of December to February, injury rates during the indoor track and field season are 16% higher than the outdoor season. Increases in injury rates are often attributed to the shorter turn radii experienced by athletes when competing on a 200m indoor track as opposed to the longer turn radii of a 400m outdoor track. A common method of counteracting these asymmetries is to bank the turns of a 200m indoor track. Aligning the athlete's resultant force vector perpendicular to the running surface can alleviate many of the running form abnormalities caused by turn running. However, the high cost of implementing a banked indoor track can be prohibitive to many programs who currently have a flat track facility. To this end, we have developed two experimental insoles designed to alleviate the asymmetries experienced during turn running: a physically angled foam insole and an insole containing an angled stiff mid-plate. Insole function was tested through human participant running trials to identify their effects on indoor flat track running mechanics. 12 NCAA Division 1 track and field athletes (6 male, 6 female, age: 21 + or - 2 years, mass: 61.4 + or - 11.4 kg, height: 1.77 + or - 0.17 m) who specialize in distance and mid-distance running provided informed consent to participate in this Institutional Review Board-approved protocol. Kinematics, muscle activation, and ground interaction variables were monitored during running trials and used to compare the effects of the insoles on running biomechanics. The physically angled insole produced positive results for ankle joint angles and ground interaction variables for turn running. The angled plate insole positively affected right-side ankle joint angle positioning and did not significantly impact straight running mechanics. Both insoles produced higher levels of muscle activation asymmetry, indicating that this may be a required effect of turn running regardless of joint angle positioning and ground interaction. While the angled plate insoles showed almost no impact on straight or turn running mechanics, the wedge insoles functioned effectively to alleviate several asymmetries related to turn running.Item Computationally modeling the aeroelastic physics of flapping-wing flight(Montana State University - Bozeman, College of Engineering, 2023) Schwab, Ryan Keith; Chairperson, Graduate Committee: Mark Jankauski; This is a manuscript style paper that includes co-authored chapters.Flying insects use flapping wings to achieve flight at minuscule sizes. These flapping wings deform elastically under both inertial and aerodynamic loading. While conventional aircraft are often designed to reduce flexibility in their wings, insects harness the benefits of wing flexibility through elastic potential energy storage and enhancement of flapping wing- specific aerodynamic phenomena. Aircraft at insect size scales could have an inexhaustible number of uses ranging from monitoring of congested piping networks in oil refineries, to extraterrestrial land surveyance in thin atmospheres. If these micro air vehicles are to be realized, however, they will need to harness the aerodynamic benefits of flapping wings in order to overcome unfavorable ratios of lift to drag forces and inefficiencies of DC motors at such small sizes. Study of flapping wing aeroelastics is complicated due to the large-amplitude rotations of the wings, unsteady dynamics of the fluid regime, and small size and weight scales of the wings. While some experimental work focuses on techniques like measuring kinematics through motion tracking with high-speed videography, and partial flow field measurements through particle image velocimetry, it is difficult to conduct experiments that paint a full picture of the fluid-structure interaction of these wings. Instead, this research focuses on high-fidelity computational modeling through bilaterally coupled computational fluid dynamics and finite element analysis software to understand the fluid-structure interaction of flapping wings. In this work, a reduced order modeling technique capable of calculating the bulk aeroelastic physics of flapping wings at computational efficiencies suitable for parameter optimization studies was also validated. Finally, the influence of tapered wing thickness on aeroelastics and energetic efficiency was studied. While wing tapering reduced mean thrust, it had a greater reduction on the energetic requirement to produce flapping kinematics and was therefore more energetically efficient.Item Investigating high-risk biomechanics in agricultural work(Montana State University - Bozeman, College of Engineering, 2022) Doud, Devon Michael; Chairperson, Graduate Committee: Scott Monfort; This is a manuscript style paper that includes co-authored chapters.Statement of Purpose: Osteoarthritis, a debilitating disease resulting in cartilage degradation and loss of mobility, is often instigated by injury or excessive loading of unconditioned articular cartilage. Although agricultural laborers are especially at risk of developing osteoarthritis, quantitative characterizations of occupation-specific activities have not previously been established. Deep flexion movements common to these groups (e.g., squatting or kneeling) may cause excessive contact forces on unconditioned cartilage, potentially initiating osteoarthritis development. Additionally, although cognitive loads can significantly alter gait mechanics, the effects of dual-task conditions (e.g., visual Stroop tests while walking) on contact forces have not previously been established. The purpose of this thesis is to better understand potential factors of osteoarthritis development in agricultural laborers by investigating occupational-specific movement patterns and joint loading during common occupational tasks. Methods: The first study evaluated seasonal differences in activity levels for farmers and ranchers by measuring movement intensity via wearable triaxial accelerometers. We hypothesized that ranchers would exhibit consistently high activity levels and that both groups would show an increase in movement intensity in their respective high seasons. The second study sought to establish the effects of cognitive challenges on tibiofemoral contact forces during normal gait and kneel-to-stand transitions in healthy adults. We hypothesized that dual-task conditions would correspond with increased peak tibiofemoral contact forces and that these forces would be positioned farther from the joint center along the mediolateral axis during dual-task conditions. Results: The first study findings largely supported the hypothesis: increased movement intensity during high seasons were recorded for both groups, with farmers exhibiting a larger seasonal fluctuation for moderate intensity activities. The second study did not support the hypothesis: cognitive loading did not significantly affect the magnitude of peak contact forces, and peak contact forces occurred closer to the joint center during dual-task conditions than during single-task conditions. However, post hoc analysis suggested that other portions of the contact force time series during stance phase were affected by cognitive challenges. Conclusions: This thesis provides foundational steps in understanding potential contributing factors of osteoarthritis development in agricultural laborers, directing future investigations towards transitional contact forces in movements simulating livestock handling.Item Practicality and usability of high-density surface electromyography for lower limb prosthesis control(Montana State University - Bozeman, College of Engineering, 2022) Christensen, Fred Wallace; Chairperson, Graduate Committee: Corey PewSurface electromyography (sEMG) presents a pathway for prosthesis control but is prone to excess noise and signal corruption due to displacement. High Density Surface Electromyography (HDsEMG), which covers the same area as Traditional sEMG with multiple electrode channels as opposed to one channel, presents a way to overcome these challenges. Seven healthy participants were recruited and performed several activities of daily living with both Traditional sEMG and HDsEMG sensors on their Rectus Femoris, Biceps Femoris, Vastus Lateralis, and Semitendinosus muscles. These sensors were placed in both optimal locations over the muscle belly and in a location 1 cm distally from that optimal placement to simulate sensor displacement with use. From the data collected, four signals were created: a Traditional sEMG signal, the single HDsEMG signal with the highest signal-to-noise ratio (SNR) (Best Signal), a time mean of all HDsEMG signals (Composite Signal), and a time mean of all HDsEMG signals with SNR values greater than 2 dB (Threshold Signal). All signals' values for SNR, root-mean-squared means (RMS), DP ratio, and Omega ratio were compared in both optimal and displaced conditions. Phase lag and power domain similarity were used to assess response to displacement. Threshold mean and straight mean signals were identical in most values. The best signal displayed highest SNR, with the composite signal displaying second highest, and sEMG displaying lowest. These differences were more pronounced in extensor muscles in activities that involved large amounts of knee movements. sEMG signals displayed higher relative RMS values, as well as higher DP values. sEMG displayed statistically higher, but numerically similar Omega values. sEMG displayed a greater agreement between optimal and displaced signals in the frequency domain. Similarity was more dependent on activity type than signal type. Phase lag was determined to not be relevant. HDsEMG was proved to have potential for improved prosthesis control.Item Improving the understanding of cognitive- motor function and lower-extremity biomechanics(Montana State University - Bozeman, College of Engineering, 2021) Fischer, Patrick David; Chairperson, Graduate Committee: Scott Monfort; Keith A. Hutchison, James N. Becker, and Scott M. Monfort were co-authors of the article, 'Evaluating the spectrum of cognitive-motor relationships during dual-task jump landing' in the journal 'Journal of applied biomechanics' which is contained within this dissertation.; Keith A. Hutchison, James N. Becker and Scott M. Monfort were co-authors of the article, 'Do dual-task demands generalize across sport-specific movements?' submitted to the journal 'Journal of applied biomechanics' which is contained within this dissertation.; Keith A. Hutchison, James N. Becker and Scott M. Monfort were co-authors of the article, 'Decoupling visual constraint from rapid decision-making effects during a jump-landing' submitted to the journal 'American journal of sports medicine' which is contained within this dissertation.Anterior cruciate ligament injuries present a considerable problem for athletic populations, especially those that engage in sports with open-skill movement demands like rapid changes of direction. These injuries typically occur in a non-contact setting, that is, the forces generated by the athlete's own movement overburden the ligaments in the knee and cause partial or total rupture of the tissue. Considerable effort has been devoted to researching and, by extension, counteracting the physical contributions to injury risk; for example, athletes are encouraged to develop better balance and lower-extremity strength to counteract the adverse effects of poor movement performance. However, anterior cruciate ligament injury risk is also tied to cognitive factors as well as physiological factors. This athlete-specific cognitive-motor relationship interacts with external distractions in the sporting environment to compromise an athlete's ability to move safely and effectively. The purpose of this research was to investigate contributions of different cognitive domains to movement performance in distracted, sport-relevant scenarios, to develop a better understanding of the cognitive-motor relationships that underpin injury rates in these athletic populations. A series of studies involving biomechanical and cognitive outcome measures demonstrated that cognitive function has an important, if not fully understood, role to play in mitigating an athlete's susceptibility to distractions during open-skill movement performance. This research adds to a critically underdeveloped body of work explaining the subject-specificity of dual-task movement performance in a lab setting and provides a foundation for developing new injury risk assessment and mitigation efforts for clinicians and coaches.Item Investigating the influence of cognitive demands and personal factors on work-body postures(Montana State University - Bozeman, College of Engineering, 2021) Nino, Luisa Valentina; Co-chairs, Graduate Committee: David Claudio and Scott Monfort; Frank Marchak and David Claudio were co-authors of the article, 'Evaluating physical and mental workload interactions in a sterile processing department' in the journal 'International journal of industrial ergonomics' which is contained within this dissertation.; Frank Marchak and David Claudio were co-authors of the article, 'Association between perceived workload and adverse body postures' in the journal 'Proceedings of the International Symposium on Human Factors and Ergonomics in Health Care' which is contained within this dissertation.Mental workload is a broad concept used by human factors and ergonomics professionals. It has become a topic of increasing importance since the introduction of technology in modern working environments. Mental workload assessment is an important component in the design of occupational tasks since inappropriate levels can cause errors, incidents, and be responsible for occupational diseases and musculoskeletal disorders. Until now, research studies have explored the effects of physical activity on mental workload. No study has analyzed the effects of mental workload on body postures even though studies have stated that in response to new information from the workplace environment, the human body orients in the direction of a stimulus, and this orientation reaction could affect the ongoing activity. This dissertation looked to 1) determine if psychosocial work factors affect perceived mental workload, 2) determine if changes in perceived mental workload generated changes in the body postures undertaken to perform an activity, and 3) explore if individual factors such as age, sex, personality traits, and anxiety mediate or exacerbate the influence of psychosocial work factors. Thirty-two participants performed two physical activities under four levels of mental workload. The results indicate, for the first time, that an increase in the perception of mental workload is associated with worse body postures that consequently could lead to work-related musculoskeletal disorders (WMSDs). Regarding the potential influence of individual factors, differences were not observed between mental workload conditions. However, individual characteristics such as anxiety, personality traits, and sex exhibited higher contributions to changes in perceived mental workload and body postures. This study is novel and contributes to overcoming an important shortcoming in the field of mental workload by considering the influence of psychosocial factors, keeping the physical load constant, on the perception of mental workload and its influence on body postures. This interaction between perceived mental workload and its effects on physical risk should be considered in occupational settings since often, employees are exposed to concurrent physical and mental demands that increase the likelihood of developing WMSDs.Item 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.Item Toward the design and characterization of a dynamically similar artificial insect wing(Montana State University - Bozeman, College of Engineering, 2019) Reid, Heidi Elita; Chairperson, Graduate Committee: Mark JankauskiMicro air vehicles (MAVs) are a useful tool for numerous tasks, such as environmental mapping, search and rescue, and military reconnaissance. As MAV applications require them to operate at smaller and smaller length scales, traditional propulsion mechanisms (e.g. fixed wings, rotating propellers) cannot meet these demands. Conversely, flapping wing micro air vehicles (FWMAVs) can to realize flight at sub centimeter-lengths. However, FWMAVs face design challenges that preclude autonomous flight, including inefficient energetics and reliable on-board sensing. A comprehensive understanding of flying insect biomechanics may provide valuable design insights to help overcome the challenges experienced by FWMAVs. Insect wings have biological sensors that provide feedback to control attitude and wing deformation improves both inertial and aerodynamic power economy. Consequently, the insect wing can guide the design FWMAV-employed artificial insect wings. The present work aims to (1) dynamically characterize real insect wings via experimental modal analysis, and (2) develop dynamically similar artificial wings to be used on FWMAVs or in controlled studies. To our knowledge, no existing artificial insect wing models are isospectral and isomodal with respect to their biological counterparts. Isomodality and isospectrality imply they have identical frequency response functions and vibration mode shapes, and thus will deform similarly under realistic flapping conditions. We measured the frequency response function and vibration modes of fresh Manduca sexta forewings using an electrodynamic shaker and planar scanning vibrometer and estimated the wings' mass distribution via a cut-and-weigh procedure. Based upon our results, we designed and constructed the artificial wings using fused filament fabrication to print a polylactic acid vein structure, based upon the actual vein size and arrangement present in biological wings. Thin polymer films were manually layered over the vein structure and trimmed to fit the wing boundaries to produce a flat wing structure. We determined that the biological and artificial wings have nearly identical natural frequencies, damping ratios, gain, and shape for the first vibration mode. The second mode exhibited complex modal behavior previously unreported in literature, which likely has significant implications to flapping wing aerodynamics. We demonstrate the feasibility of fabricating economical, realistic artificial wings for robotic applications moving forward.Item The elastic properties of bone by ultrasound(Montana State University - Bozeman, College of Engineering, 1985) LaMont, Donald Thompson; Chairperson, Graduate Committee: Michael K. WellsItem Biomechanical analysis of a cricket filiform hair socket under low velocity air currents(Montana State University - Bozeman, College of Engineering, 2012) Joshi, Kanishka Bhuwanchandra; Chairperson, Graduate Committee: Ahsan MianFiliform hairs of crickets are of great interest to engineers because of the hairs' highly sensitive response to low velocity air currents. In this study, the cercal sensory system of a common house cricket is analyzed. The sensory system consists of two antennae like appendages called cerci that are situated at the rear of the cricket's abdomen. Each cercus is covered with 500-750 flow sensitive hairs that are embedded in a complex viscoelastic socket that acts as a spring and dashpot system and guides the movement of the hair. When a hair deflects due to the drag force induced on its length by a moving air-current, the spiking activity of the neuron that innervates the hair changes and the combined spiking activity of all hairs is extracted by the cercal sensory system. The hair has been experimentally studied by researchers though its characteristics are not fully understood. The socket structure has not been analyzed experimentally or theoretically from a mechanical standpoint, and the characterization that exists is mathematical in nature and only provides a very rudimentary approximation of the socket's spring nature. This study aims to understand and physically characterize the socket's behavior and interaction with the filiform hair by presenting and proving new hypotheses about the hair and socket behavior. The operating principles of the socket can be used for the design of highly responsive MEMS devices such as fluid flow sensors or micromanipulators. A three dimensional computer aided design (CAD) model was first created using confocal microscopy images of the hair and socket structure of the cricket, and then finite element analyses based on the physical conditions the insect experiences were simulated. The results show that the socket acts like a spring but due to its constitutive non-standard geometric shapes, it deforms like a thin membrane at times or like a plate in bending at other instances. It was also determined that the socket provides far greater resistance to hair movement than what has been previously postulated and computed by researchers.