Theses and Dissertations at Montana State University (MSU)
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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 A survey of football knee injuries and causes on synthetic surfaces as compared to regular football surfaces(Montana State University - Bozeman, 1970) Watson, Richard Loys; Chairperson, Graduate Committee: Gary EvansItem Genu valgum : can observable or symptomatic changes occur with an exercise protocol in collegiate women?(Montana State University - Bozeman, College of Education, Health & Human Development, 2002) McCafferty, Jaime ErinItem Getting fixed : perceptions of rural and urban patients who have experienced total knee or hip replacement surgery and their discharge planners in a Montana hospital(Montana State University - Bozeman, College of Nursing, 1991) McIntosh, Allison MarieItem An analytical model of the patello-femoral joint(Montana State University - Bozeman, College of Engineering, 1978) Hagelin, Jack StephenItem The mechanical placement of orthopedic magnets within the human knee joint(Montana State University - Bozeman, College of Engineering, 1996) Barber, Deborah A.A mechanical analysis of an orthopedic knee implant is presented. The analysis is performed on an orthopedic knee implant that utilizes repelling magnets placed on the articulating surfaces of the tibia and the femur. The repelling magnets theoretically serve to decrease the contact force and friction within the knee joint. A three-dimensional mathematical model of the human knee joint is utilized to analyze the mechanical effects of the implants within the knee. The geometry of the surface and the effects of the ligaments are incorporated into the model. The model is evaluated at several flexion angles. The placement of the magnets within the knee joint is varied, and magnet strengths are proposed. The model is then solved for the contact forces at the knee joint with and without the implanted magnets. The decrease in contact force due to the presence of the magnets within the knee joint is evaluated. The initial implant design consisted of a total of four magnets on the femoral surface, two medial and two lateral, and two magnets on the tibial surface, one medial and one lateral. The initial design was evaluated and the conclusion was made that a more effective design could be proposed. An implant that utilized a series of three magnets on both the medial and lateral femoral surfaces repelling against a single magnet placed on both the medial and lateral aspects of the tibial plateau was analyzed. The final conclusion was made that the alternate design using six magnets on the femoral articulating surface and two on the tibial articulating surface is indicated to be the preferred mechanical placement for magnets within the human knee joint. A summary of results for the initially proposed implant design and the alternative design options are presented.Item Selected lower extremity alignment and range of motion measurements and their relationships to lateral knee pain(Montana State University - Bozeman, College of Education, Health & Human Development, 1980) Flood, Janice Elizabeth DesiItem The effects of acute muscular fatigue on the functional ability of the knee joint(Montana State University - Bozeman, College of Education, Health & Human Development, 2005) Brown, Tyler Nolan; Chairperson, Graduate Committee: Michael E. Hahn.Results of preliminary data collection indicate an increase of electromyography (EMG) amplitude in fatiguing isokinetic contractions of the knee extensors. The primary purpose of this study was to determine if the EMG/Torque relationship of vastus lateralis changes as a result of fatigue. The second purpose of this study was to determine if tests of functional ability are affected by fatigue. Twenty-two subjects (13 males and 9 females) were sampled from two populations with different types of training (strength versus endurance) experience. The procedures included a five-minute self-selected warmup on a cycle ergometer, pre-fatigue functional ability tests, fatigue protocol and postfatigue functional ability tests. The functional ability test protocol included four singleleg hopping drills to assess the functional performance of the knee joint. Torque was measured on an isokinetic dynamometer at 60 degrees per second through a functional range of motion until acute fatigue was reached during the fatigue protocol. Surface EMG electrodes were placed over the vastus lateralis to develop an EMG/Torque ratio during the dynamic contractions. The results indicate training type did not significantly affect torque production (p = 0.373) or the EMG/Torque ratio (p = 0.744) during isokinetic knee extensions in response to acute muscular fatigue. The strength-trained sample tended to have a greater increase of the EMG/Torque ratio during the fatigue protocol. The results did indicate that there were two significantly different types of response to acute muscular fatigue (p < 0.001). There were significant differences between the preand post-fatigue functional ability tests for the M/L (p < 0.001) and Up/Down (p = 0.011) but not for 3-Forward (p = 0.408) or Figure-8 (p = 0.286). One group doubled their activation magnitude during the fatigue protocol, while another group did not increase their activation magnitude during the fatigue protocol. It is possible that the increase of activation magnitude seen during the fatigue protocol is a result of transition of fiber type utilization. Further study is needed to determine what is the primary cause of the muscleαs response to acute muscular fatigue.Item Neuromuscular performance and the menstrual cycle(Montana State University - Bozeman, College of Education, Health & Human Development, 2007) Lemke, Shayna Marie; Chairperson, Graduate Committee: Mary P. Miles.Women athletes are more likely to tear their anterior cruciate ligament than their male counterparts. The female athlete has a complex system of steroid hormones that are continually changing. These sex hormones that fluctuate throughout each month may influence knee injuries, specifically the anterior cruciate ligament. The increased incidence in women is thought to be multifactorial, a combination of structural, anatomical, or biomechanical factors. The NCAA has reported that 75 percent of anterior cruciate ligament injuries are non-contact in competitive jumping or pivoting sports. In this study, the effects of the menstrual cycle on neuromuscular performance were investigated. Fifteen healthy females with regular menstrual cycles completed the various tests of this study for three phases of the menstrual cycle. All females were categorized as moderate or vigorous exercisers from an activity questionnaire. This study used a repeated measures experimental design; therefore, each participant served as her own control. The participants completed a series of two tests, including functional balance and fatigability.