Browsing by Author "Kuntze, Gregor"
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- ItemOpen AccessBiomechanical 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, HollyAnkle 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.
- ItemEmbargoBiomechanical Evaluation of the Levitation Knee Brace(2023-09-13) Baxter, Ryan Charles John; Ronsky, Janet; Kuo, Arthur; Brandon, Scott; Kuntze, Gregor; Rogers-Bradley, Emily; Charbonneau, MarieOsteoarthritis (OA) is a debilitating musculoskeletal disease affecting approximately one-third of the adult Canadian population. The most common location of OA occurring is at the knee. OA can affect all three compartments of the knee joint. Knee braces are commonly prescribed for knee OA to reduce pain and improve user function. The LevitationTM “Tri-Compartment Unloader” knee brace (Spring Loaded Technology) was designed to reduce forces in all three compartments of the knee by lowering quadriceps muscle activity, a predictor of knee joint contact force. The effect of the Levitation brace on tri-compartment joint contact forces has yet to be fully investigated. The research objective of this study was to preliminarily investigate the effect of the Levitation brace in a healthy subject on 3-dimensional (3-D) joint kinematics and kinetics, and muscle activity, using biomechanical and musculoskeletal (MSK) computer modeling assessments during a step-back lunge movement. An experimental pilot study was performed to assess the effect of the Levitation brace on joint kinematics and kinetics using a novel combined motion analysis and High Speed Biplanar Radiography approach. A musculoskeletal modelling approach was developed to analyze the effect of the Levitation brace on tri-compartment contact forces, resultant joint moments, and simulated muscle activations. The experimental study results indicate that the Levitation brace did not impact knee joint angles between bracing conditions. The brace reduced knee abduction/adduction and internal/external rotation moments when compared to the unbraced condition. The brace’s impact on flexion/extension moments was unclear. The MSK modelling results predict that the Levitation brace reduced peak contact forces in each of the knee compartments when compared to the unbraced condition. The brace increased quadriceps muscle activation and peak knee extension moments compared to the unbraced condition, contrary to what was expected. Together, the experimental and musculoskeletal modelling results provide a 3-D evaluation of the effect of the Levitation brace on tri-compartment knee joint dynamics which can be used to provide further understanding of the brace design efficacy for OA treatment, and can be applied to improve brace product design and provide insights for future product developments.
- ItemOpen AccessBone health and physical activity in adolescents with juvenile idiopathic arthritis: a cross-sectional case-control study(2024-04-19) Vasil, Egi; M. Nesbitt, Colleen; Toomey, Clodagh; Kuntze, Gregor; Esau, Shane; A. Emery, Carolyn; Gabel, LeighAbstract Background Adolescents with juvenile idiopathic arthritis (JIA) tend to engage in less physical activity than their typically developing peers. Physical activity is essential for bone development and reduced physical activity may detrimentally effect bone health. Thus, we examined differences in total body bone mineral content (BMC) and areal bone mineral density (aBMD) between adolescents with JIA and adolescent controls without JIA. We also examined associations between moderate-to-vigorous physical activity (MVPA), lean mass, and bone outcomes. Methods Participants included 21 adolescents with JIA (14 females, 7 males) and 21 sex- and age-matched controls aged 10–20 years. Assessments included: height; weight; triple-single-leg-hop distance (TSLH); MVPA by accelerometry; and total body BMC, aBMD, and lean mass measured using dual X-ray absorptiometry. Height-adjusted z-scores were calculated for BMC and aBMD and used for all analyses. Multiple linear mixed effects models examined group differences in BMC and aBMD, adjusting for sex, maturity, MVPA, TSLH, and lean mass. Participants clusters, based on sex and age (within 18 months), were considered random effects. Results Adolescents with JIA had lower total body aBMD z-scores [β (95% CI); -0.58 (-1.10 to -0.07), p = 0.03] and BMC z-scores [-0.47 (-0.91 to -0.03), p = 0.04] compared with controls. Mean daily MVPA was 22.0 min/day lower in adolescents with JIA than controls; however, MVPA was not associated with aBMD [-0.01 (-0.01 to 0.01), p = 0.32] or BMC [0.00 (-0.01 to 0.00), p = 0.39]. Lean mass was positively associated with aBMD [0.05 (0.01 to 0.09) g/cm2, p = 0.03] and BMC [0.06 (0.03 to 0.10) g, p < 0.001]. Conclusion Adolescents with JIA had lower total body aBMD and BMC compared with sex- and age-matched controls without JIA. Group differences in bone outcomes were not associated with the lower MVPA participation of adolescents with JIA. Despite this, physical activity should still be encouraged as it promotes physical well-being.
- ItemOpen AccessExamining Physical Activity, Adiposity, and Function in Youth with and without Spastic Cerebral Palsy(2018-06-27) Janzen, Leticia Mae; Emery, Carolyn; Condliffe, Elizabeth; Kuntze, Gregor; Brunton, Laura; Toomey, Clodagh M.Objectives: To examine physical activity (PA), body composition, balance, and strength in youth (ages 10-18) with cerebral palsy (CP), compared to age- and sex-matched typically developing (TD) peers. Methods: Thirty youth with CP [gross motor function classification system (GMFCS) levels I-III; 20 males], were matched to TD youth. PA (minutes in sedentary, light, and moderate-vigorous) was measured using ActiGraph accelerometers. Body composition (fat and lean mass indices) was assessed by dual-energy x-ray absorptiometry. Center of pressure (total path length and 95% ellipse area) on two force plates represented balance. Lower-extremity strength was measured using hand-held dynamometry. Results: Youth with CP, GMFCS levels II or III, achieved less moderate-vigorous PA, were more sedentary, weaker with all lower-extremity muscle groups, had lower lean mass indices, and had larger 95% ellipse areas than TD youth. Conclusions: GMFCS level appeared to impact the severity of activity limitations and of body structure and functional impairments.
- ItemOpen AccessKinematics of the head and associated vertebral artery length changes during high-velocity, low-amplitude cervical spine manipulation(2022-06-01) Gorrell, Lindsay M.; Kuntze, Gregor; Ronsky, Janet L.; Carter, Ryan; Symons, Bruce; Triano, John J.; Herzog, WalterAbstract Background Cervical spine manipulation (CSM) is a frequently used treatment for neck pain. Despite its demonstrated efficacy, concerns regarding the potential of stretch damage to vertebral arteries (VA) during CSM remain. The purpose of this study was to quantify the angular displacements of the head relative to the sternum and the associated VA length changes during the thrust phase of CSM. Methods Rotation and lateral flexion CSM procedures were delivered bilaterally from C1 to C7 to three male cadaveric donors (Jan 2016–Dec 2019). For each CSM the force–time profile was recorded using a thin, flexible pressure pad (100–200 Hz), to determine the timing of the thrust. Three dimensional displacements of the head relative to the sternum were recorded using an eight-camera motion analysis system (120–240 Hz) and angular displacements of the head relative to the sternum were computed in Matlab. Positive kinematic values indicate flexion, left lateral flexion, and left rotation. Ipsilateral refers to the same side as the clinician's contact and contralateral, the opposite. Length changes of the VA were recorded using eight piezoelectric ultrasound crystals (260–557 Hz), inserted along the entire vessel. VA length changes were calculated as D = (L1 − L0)/L0, where L0 = length of the whole VA (sum of segmental lengths) or the V3 segment at CSM thrust onset; L1 = whole VA or V3 length at peak force during the CSM thrust. Results Irrespective of the type of CSM, the side or level of CSM application, angular displacements of the head and associated VA length changes during the thrust phase of CSM were small. VA length changes during the thrust phase were largest with ipsilateral rotation CSM (producing contralateral head rotation): [mean ± SD (range)] whole artery [1.3 ± 1.0 (− 0.4 to 3.3%)]; and V3 segment [2.6 ± 3.6 (− 0.4 to 11.6%)]. Conclusions Mean head angular displacements and VA length changes were small during CSM thrusts. Of the four different CSM measured, mean VA length changes were largest during rotation procedures. This suggests that if clinicians wish to limit VA length changes during the thrust phase of CSM, consideration should be given to the type of CSM used.
- ItemOpen AccessPhotogrammetric Modelling for 3D Reconstruction from a Dual Fluoroscopic Imaging System(2019-01-03) Al Durgham, Kaleel Mansour; Lichti, Derek D.; Kuntze, Gregor; Wang, Ruisheng; Shortis, Mark R.; Boyd, Steven Kyle; Ronsky, Janet L.Biplanar videoradiography (BPVR), or clinically referred to as dual fluoroscopy (DF), imaging systems are increasingly being used to study the in-vivo skeletal biomechanics of human and animal locomotion. DF imaging provides a novel solution to quantify the six-degree-of-freedom (6DOF) skeletal kinematics of humans and animals with high accuracy and temporal resolution. Using low-dose X-ray radiation, DF systems provide accurate bone rotation and translation measurements. In this research domain, a DF system comprises two X-ray sources, two image intensifiers and two high-speed video cameras. The combination of these elements allows for the stereoscopic imaging of the bones of a joint at high temporal resolution (e.g., 120-250 Hz), from which bone kinematics can be estimated. The utilization of X-ray-based imaging results in challenges that are uncommon in optical photogrammetry. Unlike optical images, the inherent lack of colour information in DF images complicates fundamental tasks such as the derivation of image observations for the system calibration. Furthermore, the incorporation of an image-intensifier to produce DF images results in high distortion artifacts that are uncommon in optical photogrammetry. The use of image intensifiers also results in non-uniform intensity response in the DF images. Unlike optical images with well-established camera models, the systematic distortion behaviour in DF images is empirically modelled. The novelty in this research work is in providing a complete, scientific, straightforward and accurate photogrammetric framework for deriving 3D measurements from a DF imaging system. This research work provides means for automating the DF calibration procedure and introduces solutions for improving the methodology of 3D reconstruction from DF imaging. A thorough photogrammetric analysis over the system aspects points out the weaknesses in the iii traditional 3D reconstruction procedures and suggests accurate alternatives. The dissertation presents five scientific contributions: (1) a semi-automated methodology to derive the image observations from time series DF calibration images, (2) validation of an empirical DF sensor model (bundle adjustment-based) for the calibration of the DF system and introducing it as a superior replacement for the traditional direct linear transformation-based (DLT) calibration approaches, (3) a rigorous accuracy assessment methodology for the evaluation of the DF system reconstruction capabilities, (4) a novel methodology for the temporal stability analysis of an imaging system calibration parameters, and (5) a virtual-3D-model means to facilitate establishing the alignment between stereoscopic DF image pair and an MRI/CT model (2D-to3D registration).
- ItemOpen AccessPhysical Activity, Adiposity, and Functional Measures in Youth with Juvenile Idiopathic Arthritis Compared to Healthy Controls(2018-01-08) Nesbitt, Colleen; Emery, Carolyn; Ronsky, Janet; Kuntze, Gregor; Toomey, Clodagh; Benseler, SusanneObjective: To examine habitual physical activity, aerobic capacity, adiposity, and dynamic balance skills in children with JIA, inclusive of knee involvement, compared to age and sex matched healthy controls. Design: Cohort study with a matched-pair design Participants: Twenty-five youth with JIA, ages 10-20, (16 female, 9 male) were matched by age and sex to 25 healthy control participants. Methods: Physical activity data was collected using an ActiGraph accelerometer for 7 days. Aerobic capacity (relative VO2peak) was assessed by a maximal bike test. Adiposity (fat mass index) was evaluated by dual energy X-ray absorptiometry (DXA). Three dynamic balance tests examined balance performance. Results: No significant difference between groups was found in any of the outcomes after adjusting for multiple comparisons. Conclusions: Youth with JIA have similar physical activity, aerobic fitness, adiposity, and functional balance ability as their healthy peers. Differences found in physical activity between male groups could have clinical significance.