PRISM :: Browsing by Author "Edwards, William Brent"

Browsing by Author "Edwards, William Brent"

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Open Access
A Comparison of Biomechanical Outcomes in Single Leg Squat and Vertical Drop Jump in Youth and Young Adults with and without a Previous Youth Sport-Related Knee Joint Injury
(2018-04-30) Lorenzen, Kristin Nicole; Emery, Carolyn; Ronsky, Janet L.; Whittaker, Jackie L.; Edwards, William Brent; Bertram, John E.
Objective: To examine the kinematic and kinetic differences during functional movements between youth and young adults with a history of intra-articular knee injury and age, sex, and sport matched controls. Methods: In total, 186 youth/young adults (age 15-26; 100 female, 86 male; 93 matched pairs) attended a testing session in which kinematic and kinetic data were collected using a motion capture camera system and two force platforms. Joint angles and moments for the ankle, knee, hip, and trunk were calculated and between-group differences were analyzed. Results: No group differences were observed for either males or females in the primary outcomes (knee abduction/adduction angle, knee abduction/adduction moment) in either the vertical drop jump or single leg squat. Group differences were observed for the females during the vertical drop jump in the hip abduction moment on the index limb and the knee valgus angle, knee abduction moment, and hip external rotation angle on the non-index limb; during the single leg squat in the hip adduction angle on the index limb and the knee flexion angle on the non-index limb. Conclusions: Previously injured female participants demonstrate some kinematic and kinetic differences in functional movements 3-10 years following an intra-articular knee joint injury.
Open Access
The assessment of fragility fracture risk using HR-pQCT as a novel tool for diagnosis of osteoporosis
(2021-08) Whittier, Danielle Elizabeth Wein; Boyd, Steven Kyle; Schneider, Prism Steorra; Manske, Sarah Lynn; Edwards, William Brent; Forkert, Nils Daniel; Hallgrimsson, Benedikt; Jepsen, Karl
Osteoporosis is a systemic skeletal disease, characterized by reduced bone density and deterioration of bone microarchitecture, leading to increased fracture risk. However, current diagnosis using dual-energy X-ray absorptiometry (DXA) only accounts for density and consequently fails to capture most individuals who fracture. High-resolution peripheral quantitative computed tomography (HR-pQCT) is a medical imaging modality capable of characterizing three-dimensional bone microarchitecture at peripheral skeletal sites, and has demonstrated that bone microarchitecture can improve prediction of fracture risk. However, to date the improvement is modest, as interpretation of the interaction between fracture and the numerous parameters provided by HR-pQCT is complex. The objective of this dissertation was to elucidate the key microarchitectural characteristics that underpin bone fragility, and use these insights to improve assessment of fracture risk with HR-pQCT. First, reference data in the form of centile curves was established for HR-pQCT parameters using a population-based cohort (n=1,236, age 18–90 years), and a new intuitive parameter called void space was developed to capture localized regions of bone loss in HR-pQCT images. In a separate prospective multi-center cohort (n=5,873, age 40–90 years), unsupervised machine learning was implemented to identify common groupings (i.e., phenotypes) of bone microarchitecture in older adults. Three phenotypes were identified and characterized as low density, structurally impaired, and healthy bone, where the low density phenotype had the strongest association with incident osteoporotic fractures (hazard ratio = 3.28). Using the same cohort, a fracture risk assessment tool, called µFRAC, was developed using supervised machine learning methods to provide a 5-year risk of major osteoporotic fracture based on HR-pQCT parameters, and was demonstrated to significantly outperform DXA in predicting fracture risk. Finally, a new retrospective cohort of patients with fragility fractures at the hip (n=108, age 56–96 years) was used to characterize bone fragility. Hip fracture patients were significantly associated with the low density phenotype and had bone void spaces that were 2–3 times larger than controls. Together, these findings provide insight into the characteristics of bone that lead to osteoporotic fractures and introduces tools that enable insightful interpretation of HR-pQCT data for clinical use.
Open Access
Biomechanical differences between young adults with and without a history of youth sport-related ankle injury
(2022-10) Russell, Monica; Edwards, William Brent; Emery, Carolyn; Manocha, Ranita; Kuntze, Gregor; Kobsar, Dylan; Sparks, Holly
Ankle sprain injuries are common in youth sport and often have residual symptoms that linger years after the initial injury. These symptoms could include impaired balance and altered lower extremity joint kinematics and kinetics. Ankle sprain injury is strongly associated with the development of post-traumatic ankle osteoarthritis, with potential pathomechanisms linked to altered ankle joint loading. Thus, the primary objective of this research was to quantify differences in balance and lower extremity joint kinematics and kinetics between individuals who have sustained an ankle injury during youth sport 3 to 15 years prior to study participation compared to those with no history of lower extremity injury. The secondary objective of this study was to assess the impact of limb asymmetry and age on balance and lower extremity joint kinematics in individuals with and without ankle injury history during their youth. Balance did not differ between females with and without ankle sprain history. During walking, females with ankle sprain history demonstrated larger peak knee external rotation angle, larger peak knee extension angle, and larger peak hip flexion than uninjured controls. During a single-leg squat task, previously injured females displayed smaller peak ankle plantarflexion angle, peak knee extension angle, and peak hip external rotation angle than uninjured controls. Differences in ground reaction forces were observed during the walking and single-leg squat task between injured and uninjured females. During walking, older females displayed smaller peak ankle inversion, plantarflexion, hip abduction, and hip extension angles than younger females. During the SLS task, older females demonstrated a larger peak eversion angle and peak plantarflexion angle, and smaller peak knee external rotation and extension angles. . Small numbers of male participants limited analytic possibilities, however descriptively they may have a longer centre of pressure (COP) pathlength during the single-leg balance task compared to females. Male participants also seem to demonstrate different peaks in lower extremity joint kinematics compared to female participants. These results indicate long-term biomechanical effects of ankle sprain injuries, or pre-existing differences in biomechanics that may predispose certain individuals to ankle sprain injuries.
Open Access
Bone and 3D Joint Space Width Analysis in Knee Osteoarthritis using Weight Bearing CT
(2024-01-26) Waungana, Tadiwa Hanson; Manske, Sarah; Edwards, William Brent; Boyd, Steven
Osteoarthritis (OA) is the most common type of joint disorder in the world and a major cause of disability in the adult population. Globally, it is one of the fastest-growing health conditions and OA prevalence is expected to continue rising due to an aging global population. The knee is the most affected joint in OA, accounting for approximately 80% of the global OA burden, making it an important joint to consider in the context of OA. Knee OA is characterized by bone and joint structural changes, such as changes in the apparent bone mineral density, thickening of the subchondral bone plate and joint space narrowing. Detection of these changes has traditionally been considered the reserve of X-ray radiography, which is challenged by inherent anatomical overlap of a 2D imaging modality. Weight bearing computed tomography (WBCT) has recently been utilized to image and investigate OA-related structural changes in the knee, as it provides a 3D visualization of the joint whilst in a functionally relevant loaded stance. In this thesis, the utility of WBCT in measuring bone mineral density (BMD) was investigated. Next, methods to measure joint space width (JSW) subchondral bone plate thickness (SBP.Th) were implemented and tested on end-stage knee OA cohort with age- and sex- matched healthy controls. The first study showed that BMD measurement accuracy is influenced by the apparent BMD at the measurement site, with greater accuracy in trabecular bone regions. The second study demonstrated that the JSW and SBP.Th measurement methods implemented in this thesis were comparable to existing methods and able to distinguish between healthy and OA knees. A narrower JSW and thicker lateral SBP.Th in the load-bearing region of the femur was found in OA knees compared to control knees. These results show that WBCT and the implemented analysis methods may be used to measure OA-related bone and joint changes in vivo at the knee.
Open Access
Changes in Patellofemoral Joint Mechanics in the Presence of Quadriceps Muscle Imbalance
(2020-08-24) Han, Seong-won; Herzog, Walter; Edwards, William Brent; Wiley, James Preston
The purpose of this thesis was to quantify the mechanical effects of quadriceps muscle weakness and imbalance on patellofemoral joint kinematics and kinetics, and to determine the independent action of individual quadriceps muscles on the patellofemoral joint. The rabbit knee joint was used for approaching this purpose and a novel experimental technique was developed allowing for controlled activation of the individual muscles of the quadriceps group, thereby permitting simulation of any experimental joint loading scenario of interest. The primary outcome measures were the 3-dimensional patellar kinematics, and the patellofemoral joint contact pressure distribution as a function of quadriceps force, muscle weakness, and muscle imbalance. The key findings were: (i) that pressure distribution in the patellofemoral joint changed when simulating muscle imbalance and vastus medialis (VM) weakness; (ii) that patellar tracking depended greatly on knee extensor force/torque; and (iii) that the VM shifts, rotates, and tilts the patella medially throughout the range of motion. We conclude from these results that VM weakness changes the mechanics in the rabbit patellofemoral joint, and that, due to the anatomical similarity of the rabbit patellofemoral joint with other animals’ joints, including those of humans, the results may have important clinical implications. Furthermore, even though muscle imbalance induced by VM weakness altered patellar tracking, these new paths of the patella did not go beyond the range of tracking paths observed when knee extensor torques were changed from zero (passive) to maximal, thus, they may be considered within the normal range.
Open Access
Concurrent Assessment of Knee Cartilage Morphology and Bone Microarchitecture using Contrast-Enhanced HR-pQCT Imaging
(2018-05-22) Michalak, Geoffrey Jan; Boyd, Steven Kyle; Edwards, William Brent; Walker, Richard E. A.
Osteoarthritis (OA) is a prevalent articular disease characterized by degradation of articular cartilage and bone. Presently, no single imaging modality concurrently captures these changes. This study sought to develop and validate a novel joint imaging technique, contrast enhanced high resolution peripheral quantitative computed tomography (CEHR-pQCT), to concurrently assess bone microarchitecture and cartilage morphology. Cadaveric knees were harvested (n=10) and scanned using magnetic resonance imaging (MRI), HR-pQCT without contrast, and HR- pQCT following intra-articular injection of non-ionic contrast media. Joints were disarticulated, and the articular cartilage thickness measured by needle probe. Measures of cartilage morphology were found to be significantly different between MRI, needle probing and CEHR- pQCT. Bone microarchitecture was found to be significantly different in CEHR-pQCT, where cortical bone mineral density (BMD) was depressed, and trabecular BMD increased. This study contributes toward the advancement of whole joint imaging techniques, laying the foundation to perform in vivo scanning of knee cartilage and bone.
Open Access
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.
Open Access
Developing 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 Arthur
Kinesiology 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.
Open Access
Effect 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 Brent
Vitamin 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.
Open Access
Effects of Fatigue on Neuromuscular Function and Mechanical Properties in Young and Elderly Populations
(2019-08-20) Lopes Krüger, Renata; Millet, Guillaume Y.; Samozino, Pierre; Edwards, William Brent; Murias, Juan M.; Bilodeau, Martin; Kent-Braun, Jane A.; Aboodarda, Saied Jalal
Neuromuscular (NM) fatigue is defined as an exercise-related decrease in maximal power or isometric force. However, in the past 20 years, most studies have assessed isometric force only. The evaluation of dynamic measures provides important additional information to the fatigue-induced changes in NM function, especially when exploring age-related changes in fatigability. The few studies that explored dynamic measures of NM fatigue have assessed power output during single-joint movements. Therefore, measures of force production capacity (maximal power, velocity and torque) during multi-joint lower limb movements are unknown. The purpose of this thesis was to examine the effects of different intensities/durations of cycling exercises on torque-velocity properties and NM function in aging and young populations. The specific objectives were: (i) to assess kinetics of central and peripheral fatigue and recovery immediately after different cycling exercises in young individuals; (ii) to compare dynamic vs. isometric measures of NM fatigue following cycling and during recovery in young individuals; and (iii) to explore age-related differences in dynamic and isometric measures (including central and peripheral components of fatigue) of NM fatigue induced by cycling. Thanks to an innovative ergometer, NM fatigue was assessed with a minimal delay (10 s) through dynamic measures of force production capacity during 7-s cycling sprints and maximal isometric force. Our findings showed that: (i) NM fatigue is indeed determined by the exercise intensity/duration and previous studies that investigated NM fatigue with a delay (~ 3 min) might have misinterpreted fatigue amplitude and etiology as well as the course of recovery; (ii) isometric and dynamic measures behave differently after fatigue and so they are not interchangeable as they do not share the same physiological mechanisms; and (iii) younger individuals are as fatigable (for the Wingate and moderate-intensity exercise) or more fatigable (for severe-intensity exercise) than older subjects when considering isometric and dynamic measurements of NM fatigue and peripheral fatigue is greater in younger individuals after the severe- and moderate-intensity exercises, but not following the Wingate. This thesis provides the first comprehensive evaluation of age-related NM fatigue due to dynamic exercises with large muscle mass, i.e. exercises often performed in daily-life and rehabilitation activities.
Open Access
Effects of footwear and stride length on metatarsal strains and failure in running
(2017-11) Firminger, Colin R.; Fung, Anita; Loundagin, Lindsay L.; Edwards, William Brent
The metatarsal bones of the foot are particularly susceptible to stress fracture owing to the high strains they experience during the stance phase of running. Shoe cushioning and stride length reduction represent two potential interventions to decrease metatarsal strain and thus stress fracture risk.
Open Access
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.
Open Access
Effects of Minimalist Footwear and Stride Length Reduction on Metatarsal Strains and the Probability of Stress Fracture in Running
(2016) Firminger, Colin Robert; Edwards, William Brent; Boyd, Steven; Rolian, Campbell
Stress fractures are common running injuries associated with the mechanical fatigue of bone. The metatarsal bones in the foot frequently develop stress fractures due to the repetitive loading they experience while running. Similar to basic engineering materials, the number of loading cycles to bone failure (i.e., stress fracture) increases exponentially with the applied magnitude of loading. Therefore, the objective of this thesis was to examine the relative effects of two potential stress-reducing mechanisms – shoe type and stride length adjustment – on metatarsal strains and the probability of failure in running. Running in a minimalist shoe increased metatarsal strains and the probability of failure, while running with a 10% stride length reduction was not effective at reducing metatarsal strains or the probability of failure. These findings offer an explanation for why metatarsal stress fractures are frequently observed in minimalist shoe users, and suggest that running in traditional footwear lowers metatarsal strains.
Open Access
Enhanced Longitudinal Analysis of Bone Strength Estimated by 3D Bone Imaging and the Finite Element Method
(2020-10-06) Plett, Ryan Michael; Boyd, Steven Kyle; Duncan, Neil A.; Manske, Sarah Lynn; Kim, Keekyoung; Edwards, William Brent
Three-dimensional (3D) imaging with high-resolution peripheral quantitative computed tomography (HR-pQCT) and micro-finite element (FE) analysis provides important insight into bone health. Longitudinal analyses of bone morphology maximize precision by using 2D slice-matching registration (SM) or 3D rigid-body registration (3DR) to account for repositioning error between scans, however, the compatibility of these techniques with FE for longitudinal bone strength estimates is limited. This work developed and validated a FE approach for longitudinal HR-pQCT studies using 3DR to maximize reproducibility by fully accounting for misalignment between images. Using a standard imaging protocol, ex vivo (N=10) and in vivo (N=40) distal radius HR-pQCT images were acquired to estimate the efficacy of 3DR to reduce longitudinal variability due to repositioning error and assess the sensitivity of this method to detect true changes in bone strength. In our proposed approach, the full common bone volume defined by 3DR for serial scans was used for FE. Standard FE parameters were estimated by no registration (NR), SM, and 3DR. Ex vivo reproducibility was estimated by the least significant change (LSC) in each parameter with a ground truth of zero change in longitudinal estimates. In vivo reproducibility was estimated by the standard deviation of the rate of change (σ) with an ideal value that was minimized to define true changes in longitudinal estimates. Group-wise comparisons of ex vivo and in vivo reproducibility found that FE reproducibility was improved by both SM (CVRMS<0.80%) and 3DR (CVRMS<0.62%) compared to NR (CVRMS~2%), and 3DR was advantageous as repositioning error increased. Although 3D registration did not negate motion artifacts, it played an important role in detecting and reducing variability in FE estimates for longitudinal study designs. Therefore, 3D registration is ideally suited for estimating in vivo effects of interventions in longitudinal studies of bone strength.
Open Access
Enhancing the Efficiency of Subject-Specific Knee Joint Biomechanical Simulations With Applications to Osteoarthritis
(2024-08-14) Kakavand, Reza; Komeili, Amin; Edwards, William Brent; Abbasi, Zahra; Souza, Roberto M.
There are three challenges in conventional subject-specific modelling techniques. First, having an accurate material model is essential for studying biomechanical response of musculoskeletal systems. For instance, the stresses and strains in knee joint articular cartilage are influenced by site-specific variations in collagen fibril orientations that vary with aging, which is ignored in finite element (FE) analyses using a generic knee geometry. The other challenge is related to the manual geometry reconstruction from biomedical images, which is a time-consuming process and not practical for clinical applications. Finally, estimating joint forces and moments with conventional methods requires marker-based motion capture facilities to study the kinematics of human body motion and convoluted human body modeling to determine the kinetics of motions. Although marker-based motion capture offers the precise measurement of marker positions on the body and enables the calculation of kinematics and kinetics in a controlled setting, its data collection is labor-intensive and requires staff with expensive equipment and specialized technical experience. Subject-specific FE modeling provides a viable approach for the study of cartilage mechanics in normal and pathomorphological knee, thus providing insight into the mechanics of knee articular cartilage. Therefore, in this project we aimed to facilitate the development of subject-specific FE models of the knee. We developed and validated: 1) a 3D remodeling algorithm of collagen fibrils within knee joint cartilage under simulated gait, 2) a semi-automatic segmentation routine of knee joint geometry from magnetic resonance images (MRIs), and 3) a markerless motion capture to perform kinematics and kinetics analyses. To develop the cartilage fibril remodeling algorithm, a fibril-reinforced, biphasic cartilage model was integrated with 3D human knee joint geometry. For the MRI segmentation, we used 3D Swin UNETR, a statistical shape model (SSM) and automated filtering techniques to extract the distal femur, proximal tibia, femoral and tibial cartilages. To facilitate the estimation of joint forces and moments, OpenCap, a markerless motion capture software, was used during a cycling task. This technique is intended to expedite kinematics and kinetics analysis. The ultimate goal of this project is to develop an efficient pipeline for subject-specific FE modeling.
Open Access
Evidence-informed methods for predicting rehabilitation outcomes for individuals with patellofemoral pain
(2018-04-25) Watari, Ricky; Ferber, Reed; Edwards, William Brent; Hettinga, Blayne Alexander
Patellofemoral pain is a very common musculoskeletal complaint and exercise interventions are the treatment of choice for this condition. However, 15% to 40% of patients present a poor response to rehabilitation and identifying objective measures that can help screen patients who are more likely to present successful results after rehabilitation is important for the optimization of treatment strategies. Therefore, the overarching purpose of this thesis is to develop evidence-based methods for predicting the outcome of exercise treatment in young recreational runners with patellofemoral pain. We found that a classification model using data from conventional motion capture system was able to distinguish between treatment responders and non-responders with 78% of accuracy. To make this classification model more accessible in a clinical setting, we tested whether pelvic acceleration patterns during running could be clustered into homogeneous sub-groups of individuals with patellofemoral pain. We identified two clusters for females and one cluster for males, indicating the clinical utility of this approach for the identification of patient sub-groups. The next study developed a classification model based on pelvic acceleration data to classify patients according to treatment response, achieving an 85% classification accuracy and showing a more clinically accessible approach. Finally, we tested the equivalency of marker-based and inertial measurement unit-based segment acceleration data when applied to a random classification problem in order to understand if the latter classification model could be applied using wearable devices. Overall, the findings indicated a 35% likelihood of decrease in performance of classifiers when the input data were crossed over from different sources. Therefore, a new classification model would have to be developed using data from wearable sensors to facilitate the implementation of this method in a clinical setting. We conclude that the outcome of exercise intervention protocols for the treatment of patellofemoral pain can be predicted using baseline gait analysis data with systems that can be applied in a laboratory setting and has the potential of being translated to a clinical setting as well.
Open Access
Exercising horses on water treadmills: Understanding the workload, mechanics, and conditioning effects of water treadmill exercise.
(2019-10-22) McCrae, Persephone; Léguillette, Renaud; Millet, Guillaume Y.; Edwards, William Brent; Rolian, Campbell
Despite the growing popularity of equine water treadmills (WTs), there is very little scientific evidence to support their use in the conditioning or rehabilitation of sport horses. As a result, the success of WT use is in large part dependent on the ability of the operator to assess and create an appropriate plan. Therefore, the projects described in this thesis were established to assess the workload, conditioning effects, and limb kinetics and kinematics associated with equine WT exercise. The results gathered from these studies will allow more evidence-based use of equine WTs for training and rehabilitation. It was essential to first understand the effort required during WT exercise. We found that water height had a greater impact on workload than the speed of the treadmill belt. The greatest workload occurred with water at the height of the stifle, however this was still considered to be a relatively low-intensity exercise. Using our understanding of workload from the first study, the second study aimed to assess the conditioning effects of a WT exercise program. We assessed the fitness of horses before and after 18-days of WT training, including a dry control (exercised without water), using a maximal intensity exercise track test. Peak oxygen consumption, as tested on the racetrack, increased significantly in the experimental horses, indicating that despite the low workload on the WT, exercising horses in high water heights improves fitness. As the primary rationale for using WTs is to reduce concussive forces experienced by the limb, the third study evaluated the effect of water height and speed on segmental acceleration and impact attenuation during WT exercise. The unique properties of water, especially when water was used at a high level, resulted in reduced segmental accelerations and increased attenuation. These findings suggest that WT exercise may be beneficial in the rehabilitation of lower limb injuries in horses. Lastly, we examined 2-dimensional forelimb kinematics of horses on land and under various WT conditions before and after 8-days of WT conditioning. We found that water height alters limb kinematics and may be meaningful for physical rehabilitation. However, prolonged exposure to WT training does not have a lasting effect overground kinematics. Altogether, these studies have elucidated objective information that will serve as the foundation for the effective and safe use of WTs in the training and rehabilitation of performance horses.
Open Access
Experimental Measurement and Applied Modelling of Patellar Tendon Strain
(2021-05-27) Firminger, Colin Robert; Edwards, William Brent; Stefanyshyn, Darren; Hart, David
Patellar tendinopathy is an overuse injury that occurs from repetitive loading of the patellar tendon in a scenario resembling mechanical fatigue. Tendon strain is correlated with the number of repetitive loading cycles that can be withstood prior to fatigue failure, and therefore represents a potential metric to infer patellar tendinopathy risk. To this end, I first quantified the mechanical fatigue behaviour of the patellar tendon in a cyclic loading scenario. I discovered that initial peak nominal strain, initial peak median strain, creep rate, and damage rate all displayed significant power law relationships with fatigue life. Based on the non-linear relationship between strain and fatigue life, I examined the effect of shoe outsole stiffness and surface construction on in vivo estimates of patellar tendon strain with the aim of exponentially increasing the number of jumps that could be performed prior to fatigue failure. Unfortunately, I discovered that neither intervention altered patellar tendon strain during jumping, potentially because the differences in shoe stiffness and surface construction were not large enough to require kinetic and/or kinematic changes at the knee. Finally, I assessed the effect of two strain estimation methodologies with varied levels of subject-specificity on fatigue-life estimates. I discovered that nominal strain models overestimated patellar tendon fatigue life compared to finite element models as they do not account for strain concentrations both within the tendon midsubstance and near the entheses, while fatigue-life estimates from both finite element and nominal strain models were sensitive to the use of generic material properties but not generic geometry. The results of these studies form a principled basis for the estimation of patellar tendon strain and additional time-dependent metrics to characterize patellar tendinopathy risk from a mechanical fatigue perspective, and further illustrate appropriate methodological approaches to do so.
Open Access
Experimental validation of finite element predicted bone strain in the human metatarsal
(2017-01) Fung, Anita; Loundagin, Lindsay L.; Edwards, William Brent
Metatarsal stress fracture is a common injury observed in athletes and military personnel. Mechanical fatigue is believed to play an important role in the etiology of stress fracture, which is highly dependent on the resulting bone strain from the applied load. The purpose of this study was to validate a subject-specific finite element (FE) modeling routine for bone strain prediction in the human metatarsal. Strain gauge measurements were performed on 33 metatarsals from seven human cadaveric feet subject to cantilever bending, and subject-specific FE models were generated from computed tomography images. Material properties for the FE models were assigned using a published density-modulus relationship as well as density-modulus relationships developed from optimization techniques. The optimized relationships were developed with a 'training set' of metatarsals (n=17) and cross-validated with a 'test set' (n=16). The published and optimized density elasticity equations provided FE-predicted strains that were highly correlated with experimental measurements for both the training (r2≥0.95) and test (r2≥0.94) sets; however, the optimized equations reduced the maximum error by 10% to 20% relative to the published equation, and resulted in an X=Y type of relationship between experimental measurements and FE predictions. Using a separate optimized density-modulus equation for trabecular and cortical bone did not improve strain predictions when compared to a single equation that spanned the entire bone density range. We believe that the FE models with optimized material property assignment have a level of accuracy necessary to investigate potential interventions to minimize metatarsal strain in an effort to prevent the occurrence of stress fracture.
Open Access
Experimental Validation of Finite Element Predicted Bone Strain in the Human Metatarsal
(2017) Fung, Anita; Edwards, William Brent; Boyd, Steven Kyle; Schmidt, Tannin; Li, Leping; Wiley, James Preston
The objective of this study was to verify and validate a finite element modeling routine for the human metatarsal, which is a common location for stress fractures. Experimental strain measurements on 33 human cadaveric metatarsals subject to cantilever bending were compared with strain predictions from finite element (FE) models generated from computed tomography images. For the material property assignment of the FE models, a published density-elasticity relationship was compared with density-elasticity equations developed using optimization techniques. The correlations between the measured and predicted and predicted strains were very high (r2≥0.94) for all of the density-elasticity equations. However, the utilization of an optimized density-elasticity equation improved the accuracy of the finite element models, reducing the maximum error between measured and predicted strains by 10% to 20%. The finite element modeling routine could be used for investigating potential interventions to minimize metatarsal strains and the occurrence of metatarsal stress fractures.