Browsing by Author "Stefanyshyn, Darren John"

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    Determining Speed and Stride Length using an Ultrawide Bandwidth Local Positioning System
    (2021-01-13) Singh, Pratham P.; Stefanyshyn, Darren John; Boyd, Jeffrey Edwin; Edwards, William Brent; Ferber, Reed; Yanushkevich, Svetlana N.
    There are many modalities that can profile speed and stride length for runners. One such modality includes using wearable technologies. An example of a wearable technology includes a global positioning system-based wearable. However, due to its limitations, an alternative may include a local positioning system-based wearable operating in the ultrawide bandwidth. Considering that a local positioning system is not good at determining gait events such as heel and step count, applying sensor fusion with an inertial measurement unit may be beneficial. Therefore, the purpose of the dissertation was to compare speed and stride length determined from an ultrawide bandwidth local positioning system equipped with an inertial measurement unit to a criterion standard (i.e. the “gold standard”) such as video motion capture and timing gates. The data suggest that the local positioning system used in the project may not be a valid tool without further processing. Using machine learning algorithms, pertinent features from a gait cycle that can better extract speed and stride length were explored. More specifically, using a stepwise linear regression model first and then using a feedforward neural network proved to be quite successful in estimating stride length. Chapter 1 provides an introduction to the project, Chapter 2 provides a review of relevant literature, Chapter 3 provides an insight into the materials and methods used, Chapter 4 shows the results obtained from the methods described earlier, Chapter 5 is a discussion of the results obtained and Chapter 6 concludes with suggestions regarding next steps that should be taken.
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    Effects of midsole cushioning stiffness on Achilles tendon stretch during running
    (2020-12-09) Esposito, Michael Jonathan Stuart; Stefanyshyn, Darren John; Edwards, William Brent; Aboodarda, Saied Jalal
    Footwear midsole material can have a direct influence on running performance. However, the exact mechanism of improved performance remains unknown. It is speculated that changes to midsole stiffness may influence the energy return from the Achilles tendon, reducing the metabolic cost. The purpose of this study was to determine if changes in footwear midsole stiffness elicit changes in Achilles tendon stretch, and it was hypothesized that the footwear condition with better running economy for an individual will have greater Achilles tendon stretch. Fourteen runners with personal best 10km times less than 40 minutes completed two testing sessions. Two footwear conditions were evaluated and consisted of a stiff and compliant midsole. Session one determined the moment arm of the Achilles tendon using dynamometer testing. Session two was a treadmill running session where kinetics, kinematics, metabolic and ultrasound data were collected while participants ran at a submaximal speed in each shoe condition. Main outcome variables were differences in Achilles tendon pseudo-stretch and differences in running economy, quantified as the energy cost of running. Correlation analysis was performed to assess the existence of a linear relationship between the variables. There was a moderate positive correlation between the difference in pseudo-stretch and the difference in running economy, which was statistically significant (r = 0.563, p = 0.036, d = 0.58). Twelve participants had greater pseudo-stretch and better running economy in the same footwear condition and two participants did not have greater pseudo-stretch and better performance in the same footwear condition. Based on estimates, the difference in energy returned from the Achilles tendon was 3.8 % on average of the mechanical energy required per step. Energy returns of this magnitude would be relevant and could cause the improved running economy observed. These results suggest that the energy returned from the Achilles could be a valid mechanism for improving running economy due to changes in footwear. These findings lead the way for future research to further understand the mechanism behind improved running economy. Understanding how footwear modifications affect internal mechanisms could have large ramifications on potential strategies for assisting and supporting locomotion.
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    Mechanical energy contributions of the lower extremity joints to athletic performance
    (1996) Stefanyshyn, Darren John; Nigg, Benno M.
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    Shoe Bending Stiffness and Muscle-Tendon Unit Function in Running
    (2021-01-08) Čigoja, Saša; Nigg, Benno Maurus; Edwards, William Brent; Stefanyshyn, Darren John; von Tscharner, Vinzenz; Boyd, Steven K.; Hoogkamer, Wouter
    The latest records set during long-distance running competitions have been attributed to recent footwear midsole innovations. One of these midsole innovations that has been claimed to have large effects on biomechanical, physiological, and performance variables is the use of a carbon fibre plate to increase the longitudinal bending stiffness of a shoe. Several mechanisms were proposed to be associated with performance improvements when running in footwear with carbon fibre plates. One of these mechanisms, the principle of optimising muscle function is currently not well understood. Therefore, this thesis aimed to investigate the effects of midsole bending stiffness of athletic footwear on muscle and muscle-tendon unit function in running. The first part of this thesis showed that running in stiff footwear resulted in a redistribution of positive work from proximal to distal lower limb joints. Specifically, it was found that a fatigue-induced redistribution of joint work from distal to proximal joints can be delayed when running in stiff footwear. The second part of this thesis dealt with the shortening velocities of muscle-tendon units. Estimated shank muscle-tendon unit shortening velocities were reduced when running in stiffer shoes. Experimental results using ultrasound imaging of the gastrocnemius medialis muscle revealed that the muscle shortened to a lesser extent and with lower average velocities in stiff running footwear. These findings could have implications for long-distance running performance. Positive work generation at more distal joints (i.e., ankle) may result in lower active muscle volume, which has been shown to be the main determinant of changes in the energetic cost of running. Slower shortening velocities of the gastrocnemius medialis could allow the muscle to operate on a more favourable position on its force-velocity relationship. This could allow for more economical force generation for a longer period during long-distance running. Altered muscle function could be a source of improved performance when running in stiff shoes.
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    A Study in Performance Footwear: The Design of a Wakeskate Shoe
    (2019-04-11) Vodon, Kristine; Wylant, Barry; Stefanyshyn, Darren John
    At the intersection of wakeboarding and skateboarding, the sport of wakeskating has emerged and captured the interest of many young and daring athletes. As a watersport that utilizes a griptape board, wakeskaters are able to perform skateboarding moves on the water. This extreme set of circumstances places unique demands on a rider’s footwear while they encounter water, grip-tape, dirt, sand, and gravel. This Master’s Thesis sets out to explore the question: can an effective and sustainable footwear design be generated to address the high-performance requirements of wakeskating? The purpose of this research is to propose the design of a wakeskate shoe which evolves from the theory of three core conceptual frameworks. The first of these is the user-centred design framework establishing a design approach that focuses on the user at the heart of the research. Next is the framework of sustainable development, identifying the opportunities for an environmentally, socially, economically and culturally sustainable design. Lastly, the parameters of the footwear industry are explored to ensure a strong understanding of the industry sector for this project. From the literature review of the conceptual framework and primary research including key informant interviews, user surveys, and Human Performance Lab testing, a synthesis of the findings takes shape as a design brief intended to inform the resulting design project. The wakeskate shoe design that emerges from this brief should operate using a sustainable business model, while implementing the use of sustainable materials and processes. The design must also address fundamental user needs such as quick drying, optimizing board feel, and providing durability in the toe, lateral forefoot, and counter, resulting in a longer-lasting shoe. The outcome of these efforts aim to produce a sustainable piece of footwear design that meets the demands of a rider engaged in the sport of wakeskating.