Browsing by Author "Bertram, John Edward Arthur"
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- ItemOpen AccessDeveloping procedures and software for correcting artifacts in motion data(2019-04-25) Chen, Alexander Wen; MacIntosh, Brian R.; Edwards, William Brent; Syme, Douglas A.; Bertram, John Edward ArthurKinesiology relies upon accurate, reliable recordings of movements. Two common techniques for obtaining such recordings are sonomicrometry and optical marker-based motion capture. Although commonly used, sonomicrometry and motion capture are often limited by the presence of artifacts that require correction. Unfortunately, the standard approach to artifact correction in kinesiology is a manual, time-intensive process that requires expertise and painstaking effort to verify. Therefore, to improve the efficiency and consistency of motion data analysis, we have developed procedures and software tools for the correction of artifacts in sonomicrometry and motion capture. Our work on sonomicrometry provides a framework for artifact correction that is more transparent, easier to use, and requires fewer and more limited manipulations from the user compared to existing approaches. Our work on motion capture provides a biomechanically-principled approach to cleaning motion capture data using a dynamic Bayesian network.
- ItemOpen AccessDirect Measurement of the Change in In-vivo Stresses in Ovine Stifle Joints following Trauma Using Fiber Optic Sensors(2019-04-30) Vakiel, Paris; Shrive, Nigel; Dennison, Christopher; Hart, David; Bertram, John Edward Arthur; Sadak, Leszek Jozef; Fleming, BradenUnderstanding stresses within the joint is central to understanding the etiology and progression of osteoarthritis (OA), as well as the effects of clinical interventions meant to slow or halt OA progression. It’s been hypothesized that a change in stress is a significant factor in the initiation and progression of post-traumatic osteoarthritis. Without a reliable method for measuring stress this hypothesis has largely gone untested. This study was aimed at testing this hypothesis by developing and implementing an alternative stress sensing technology. Currently the most widely used method for measuring contact stresses is stress sensitive films. Their use requires a significant amount of dissection and removal of biomechanically relevant structures. Their presence in the joint alters the natural mechanics and the lubrication properties of the joint. There are also significant errors associated with the thickness and curvature, and modulus dependency resulting in large errors and unreliable data. To address the existing knowledge gap small fibre optic sensors capable of measuring normal stress between contact surfaces in diarthrodial joints were developed. The small size of these sensors (diameter of 125-300 μm and sensing length of 1 mm) allows these sensors to be inserted into the joint space without the removal of biomechanically relevant structures. Fibre optic sensors specifically designed to be inserted into ovine knee joints were used to measure in-vivo stresses on the surface of the cartilage for both healthy and surgically damaged joints. Undeniably the most important finding of this study was the correlation iii between changes in average and peak stress values following trauma and the likelihood of the development of focal damage at each position signaling the onset of post-traumatic osteoarthritis. Another important result in the non-uniformity of stress under the meniscus. This study successfully addressed many of the challenges associated with the use of fibre optic sensors to obtain repeatable in vivo stress measurements, validating an innovative technique for measuring stresses in the knee joint. Along with our capability to reproduce invivo motions accurately and the improvements of fibre optic technology, this study is the first accurate, direct measurement of stress in a joint during in-vivo gait replication.
- ItemOpen AccessEffect of Increased 25(OH)D on Bone Health, a High Resolution Peripheral Computed Tomography Study(2016) Hildebrandt, Erin Marie; Boyd, Steven Kyle; Hanley, David Arthur; Bertram, John Edward Arthur; Nettel-Aguirre, Alberto; Kothandaraman, Maitreyi; Edwards, William BrentVitamin D is important for normal bone health, however, there is still debate over the intake for optimal bone health. The objective of this study is to assess the relationship between large changes in 25(OH)D to bone health, and the safety of taking up to 10,000 IU/day of vitamin D over one-year using a pilot cohort of a three-year ongoing randomized control trial. The results suggest that with increased 25(OH)D there was an improvement in trabecular and cortical BMD, as well as a decrease in cortical area and thickness, while maintaining bone strength. Based on biomarker data, taking doses of vitamin D up to 10,000 IU/day for one year was found to be safe within the population studied. This study has provided new insight into the understanding of large changes in 25(OH)D on bone health and demonstrates the importance of 25(OH)D for maintaining bone health in a healthy adult population.
- ItemOpen AccessInvestigating Bone Remodelling in Knee Osteoarthritis using HR-pQCT Imaging(2023-05-12) Kaketsis, Daphne Angelique; Manske, Sarah Lynn; Bertram, John Edward Arthur; Boyd, Steven Kyle; Edwards, William Brent; Zimmermann, Elizabeth AnnOsteoarthritis (OA) is the most common type of arthritis and a significant cause of disability worldwide. With an aging population in Canada, the prevalence and burden of OA is expected to increase. Knee OA is the most common form of OA, comprising upwards of 30% of cases. Early-stage OA can be difficult to diagnose, as often times pain and radiographical evidence do not align; however, abnormal subchondral bone remodelling has been considered to have an important role in OA pathogenesis, and some propose that it could offer a target for OA treatment. Clinically, measures of bone remodelling have been performed on iliac crest bone biopsies that are invasive and do not capture local changes. Recently, high resolution peripheral quantitative computed tomography (HR-pQCT) has been utilized in several different ways to analyse bone dynamics, or how the bone changes over time. These measurements are sensitive to several factors such as noise and motion but have yet to be validated in humans. The purpose of this study was to determine whether HR-pQCT can be used to measure longitudinal bone remodelling at the knee in humans with knee OA. Longitudinal bone remodelling results were compared to same-day rescan images to conduct a repeatability analysis. There were no significant differences between longitudinal and rescan results for bone formation (p = 0.47), bone resorption (p = 0.12), or net bone remodelling (p = 0.748). Additionally, the least detectable changes measured were 10.88% for bone formation, 10.53% for bone resorption, and 4.05% for net bone remodelling. These results indicate that with the current imaging procedures, there is too much error in the scans and processing pipeline to measure bone remodelling longitudinally in-vivo in the knee.
- ItemOpen AccessLocomotor biomechanics and behaviour in the ocellate river stingray(2020-04-22) Seamone, Scott G.; Syme, Douglas A.; Bertram, John Edward Arthur; Post, John R.; Standen, Emily M.; MacInnis, Martin J.Stingrays are fishes that are dorsoventrally flattened in the same plane as the substrate, similar to a hydrofoil, with long thin tails that have an absent or reduced caudal fin, and anterior to the pelvic girdle the longitudinal body axis is relatively rigid. These characteristics would appear to constrain or preclude many of the locomotor behaviours that are employed by fishes that typically swim via undulations of the longitudinal body axis and caudal fin, and which tend to dominate descriptions of fish swimming in the literature. In contrast, stingrays exhibit a variety of locomotor behaviours powered via enlarged and flexible pectoral fins that wrap around the body and head (i.e. the pectoral disc), yet an in-depth understanding of the biomechanical mechanisms that permit these behaviours has not been formed. Potamotrygon motoro, the ocellate river stingray, lives along the substrate in a benthic environment, and possesses an extremely rounded pectoral disc, from the dorsal view. It is used in these studies to represent the flattened shaped, low profile, and relatively rounded disc common to benthic stingrays, to better understand how these animals achieve different locomotor behaviours. The studies described in this thesis offer insight into how the shape of P. motoro is employed to accomplish behaviours exhibited by many benthic stingrays such as fast-start maneuverability, station holding and burying. Chapter 1 reviews our current and somewhat limited understanding of how shape impacts swimming behaviour in fishes that are flattened in the same plane as the substrate, described here as foil fishes, and explores relationships of shape and ecology observed in stingrays. Chapter 2 describes studies where video analysis was used to reveal that flexibility in the movements of the pectoral fins around the flattened and nearly symmetrical disc shape permits fast-start escape in all directions across the benthic plane with similar performance, regardless of initial orientation of the fish, which appears to challenge the conventional description of maneuverability typically used to evaluate fishes. Chapter 3 describes studies where recordings of changes of pressure beneath the pectoral disc, and video observations of movements of dye, are used to argue that stingrays can exercise movements of the body and fins to flush water from beneath the ventral surface to create and maintain a seal between the pectoral disc and benthos, to achieve suction pressures via a vacuum and possibly Stefan adhesion, that can resist an upwards displacing force to hold station along the benthos. Chapter 4 describes studies that used video analysis and particle image velocimetry to explain how rapid and vigorous movements of the body and fins in stingrays fluidize and suspend vortices of sediment below the ventral surface of the fins, which are then directed up and over onto the dorsal surface to cover the fish with sediment and effect burying, and that the fish appear to direct and control these vortices to modulate the extent and pattern of burying. Chapter 5 describes studies that used time-lapse photography and video analysis to reveal that in the presence of sediments that differ in grain size, stingrays mostly choose to inhabit and bury in finer grained sediments when threatened, and this appears to reflect these fishes being more effective at burying in finer sediments, such that the rate of coverage of the dorsal surface is faster for a given finbeat speed. Chapter 6 provides a summary of what has been revealed by these studies, conclusions and future directions. These studies advance our understanding of how a flattened and rounded disc shape in P. motoro might find success in a benthic environment, and might inspire engineers interested in fish for the design of underwater robotics.
- ItemOpen AccessMechanics and Energetics of Force Production in Muscle(2023-09-22) van der Zee, Tim Jonathan; Kuo, Arthur D.; Bertram, John Edward Arthur; Herzog, Walter; Fletcher, Jared R.; MacIntosh, Brian Robert; Campbell, Kenneth S.The mechanics and energetics of skeletal muscle force production are important for many movements, including locomotion. But they have been characterized primarily for steady conditions such as constant shortening velocity and fixed muscle length, rather than dynamic or cyclic conditions that resemble daily movements. Although musculoskeletal models are intended to predict how muscles behave during movement, there have been few quantitative experiments to inform such models. In this thesis, I experimentally examine muscle mechanics and energetics for cyclic conditions, and then apply those data to develop a new computational model of muscle. The model reproduces activation and force development dynamics observed experimentally, is more mechanistic than current Hill-type models, and better matches energy expenditure for cyclic conditions. A simple summary of these effects is that muscle behaves like a low-pass filter with respect to excitatory input. A filter predicts a sharp increase in energetic cost with faster cyclic conditions, in agreement with empirical data (Chapter 2). To facilitate quantification of muscle mechanics in vivo, I developed an algorithm to track muscle fascicles in ultrasound images, named ‘TimTrack’ (Chapter 3). Much of the energetic cost of cyclic force production was not explained by traditional measures of work or force, but by rate of force development (termed ‘force-rate’). To expand on the low-pass filter, I proposed a model that combines muscle dynamics with steady relations and series elasticity. Unlike existing models, the proposed model predicts muscle force development across a broad range of conditions in a self-consistent manner (Chapter 4). An essential aspect is a set of dynamics intermediate to calcium activation and muscle cross-bridges, here termed force facilitation. These dynamics help explain the energetic cost of both steady and cyclic muscle contractions, in qualitative agreement with the simple low-pass filter (Chapter 5). Model simulations suggest that most of the force-rate cost is due to increased calcium transport at higher muscle excitation levels. The experiments and computational modeling presented here demonstrate energetic costs not previously identified or modeled and have potential to improve understanding of how muscles contribute to daily movements.
- ItemOpen AccessMinimally actuated walking: Identifying core challenges to economical legged locomotion reveals novel solutions(Frontiers Media, 2018-05-22) Schroeder, Ryan T.; Bertram, John Edward ArthurTerrestrial organisms adept at locomotion employ strut-like legs for economical and robust movement across the substrate. Although it is relatively easy to observe and analyze details of the solutions these organic systems have arrived at, it is not as easy to identify the problems these movement strategies have solved. As such, it is useful to investigate fundamental challenges that effective legged locomotion overcomes in order to understand why the mechanisms employed by biological systems provide viable solutions to these challenges. Such insight can inform the design and development of legged robots that may eventually match or exceed animal performance. In the context of human walking, we apply control optimization as a design strategy for simple bipedal walking machines with minimal actuation. This approach is used to discuss key facilitators of energetically efficient locomotion in simple bipedal walkers. Furthermore, we extrapolate the approach to a novel application—a theoretical exoskeleton attached to the trunk of a human walker—to demonstrate how coordinated efforts between bipedal actuation and a machine oscillator can potentially alleviate a meaningful portion of energetic exertion associated with leg function during human walking.
- ItemOpen AccessModels of Energetically Optimal Locomotion in Cursorial Mammals(2020-02-14) Polet, Delyle Thomas; Theodor, Jessica M.; Bertram, John Edward Arthur; Pieper, Jeffery Kurt; Syme, Douglas A.; Kuo, Arthur D.; Carrier, David R.It is widely held that cursorial mammals use gaits that minimize the energetic cost of locomotion, but it is hard to compare alternative strategies in real organisms. In this thesis, I show how simple models can inform and predict the gaits used by cursorial mammals from an energetics perspective. A simple work optimization model predicts how human subjects reduce their takeoff velocity and "bounciness" while running in reduced gravity. This work-based perspective is extended to quadrupeds using trajectory optimization, where it is shown that an additional term– the so-called force-rate penalty– is necessary to explain some features of canid locomotion. The shape of ground reaction forces, leg sequence at slow to moderate speeds, changes in duty factor at moderate to fast speeds, and the walk-trot transition are all predicted by this planar model. Next I use this model to show how changing pitch moment of inertia affects energy-optimal gait choice, matching gait preferences between dogs, horses, giraffes and elephants. Finally, I compare various modelling approaches used for four-legged mammals, and show how center-of-mass considerations alone do not explain the typical, four-beat walking gait used by most cursorial quadrupeds– despite the success of the center-of-mass approach in humans, as demonstrated in this very thesis. These results show that energetic optimization can be remarkably predictive of gait choice in mammalian cursors, even with a small number of modelling components. Where the predictions are deficient, they point to missing levels of complexity that could be added in future models.
- ItemOpen AccessProperties of traditional bamboo carrying poles have implications for user interactions(Public Library of Science (PLoS), 2018-05-10) Schroeder, Ryan T.; Croft, James L.; Ngo, Giang D.; Bertram, John Edward ArthurCompliant bamboo poles have long been used for load carriage in Asian cultures. Although this custom differs from Western conventions of rigid body attachments (e.g. backpack), potential benefits include reduced peak shoulder forces as well as metabolic transport cost savings. Evidence that carrying a flexible pole benefits locomotion remains mixed, perhaps in part because the properties of pole design (e.g. bamboo material, structural geometry, etc.) have largely been neglected. These properties influence vibrational forces and consequently, the energy required by the user to manage the oscillations. We collected authentic bamboo poles from northern Vietnam and characterized their design parameters. Four poles were extensively studied in the lab (load-deflection testing, resonance testing, and computed tomography scans of three-dimensional geometry), and 10 others were tested at a rural Vietnamese farm site (basic measures of form and resonance). A mass-spring-damper model was used to characterize a relationship between resonant frequency (which affects the energetics of the pole-carrier system) and pole properties concerning stiffness, damping, etc. Model predictions of resonant frequencies agreed well with empirical data. Although measured properties suggest the poles are not optimally designed to reduce peak oscillation forces, resonant frequencies are within range of a typical human walking cadence, and this is likely to have a consequence on locomotion energetics.
- ItemOpen AccessA test of the effect of hindlimb elongation on jumping performance using Longshanks mice(2019-04-26) Bradley, Madison Meta; Cote, Susanne; Rolian, Campbell; Bertram, John Edward Arthur; Syme, Douglas A.This study is the first to study mammalian jumping performance at the population level by using a forward-engineered body plan. Jumping mammals, including jumping primates, have long hindlimbs relative to their forelimbs and relative to generalized quadrupedal species. The influence of hindlimb elongation on the dynamics of jumping has rarely been studied within a species, especially within mammals. The Longshanks mice, which were selectively bred for longer tibiae, allowed for a direct test of which aspects of jumping dynamics change when an animal has relatively longer hindlimbs. Longshanks mice voluntarily jumped higher than random-bred Control mice. Near behavioral maximum, Longshanks exerted lower maximal ground reaction forces than Control mice jumping to the same height. Using Longshanks, I was able to link hindlimb elongation with differences in hindlimb force generation that occur independent of muscular changes. These biomechanical data can help to understand the selective advantages that shaped the extreme elongation of hindlimbs in jumping primate species.
- ItemOpen AccessTowards the Real-time Monitoring of Achilles Tendon Strain(2018-07-18) Bruce, Olivia Leigh; Edwards, William Brent; Stefanyshyn, Darren J.; Wiley, James Preston; Bertram, John Edward ArthurAchilles tendinopathy is an overuse injury affecting jumping athletes, associated with the accumulation of microdamage due to repetitive tendon strain. Surface and footwear modifications may influence tendon strain magnitude. The purpose of this thesis was to examine the influence of surface and footwear modifications on Achilles tendon strain during vertical countermovement jump landings and to quantify the relationship between tendon strain and accelerometer measures. The parameters were quantified for three shoes (Boost™, 55C, and 70C) and three surfaces (ACS, BC3, and MVP) using motion capture, accelerometry, and dynamometry-ultrasound measures. Surface and footwear influenced Achilles tendon strain; strain was lower in the Boost™ shoe and MVP surface conditions. Differences in strain could be due to stiffness or other material properties of the shoes and surfaces. Only weak correlations were found between tendon strain and accelerometer measures, suggesting that data obtained from accelerometers may not reflect internal loading.