Background and objectives: Coronary artery disease (CAD) is the leading cause of death among women both nationally and internationally. Despite increased knowledge regarding CAD in women, early diagnosis remains a difficult clinical task. A correlation between peripheral arterial disease (PAD) and CAD has been noted in previous research; however, these studies were either retrospective or did not focus on women. This research investigates the correlation of ankle brachial index (ABI), measurements used to diagnose PAD, and presence of CAD in women, in an effort to determine the predictive value of ABI specifically in women. Subjects and methods: A prospective correlation design was used to study women (n = 30) who were undergoing a diagnostic cardiac catheterization. Ankle brachial index readings were obtained prior to the catheterization procedure. Catheterization findings were grouped according to absence of CAD or presence of 1-vessel or multivessel CAD and coupled with each woman's ABI and recorded cardiovascular risk factors. Results: Peripheral arterial disease (based on ABI of <0.90 mm Hg) was found in 13.3% of the women. A significant correlation was found between ABI of less than 0.90 mm Hg and increasing age (t = -2.30, P =.029). Coronary artery disease was found in 82.1% of the women; more than half (57.1%) had multivessel disease. Absence of CAD was noted in 17.9%. Women with CAD were older than women without CAD (F = 3.86, P =.035). No significant differences were found between presence or absence of PAD based on ABI and diagnosis of no coronary disease or 1-vessel or multivessel coronary disease. Conclusions: This study failed to show the expected correlation between ABI of less than 0.90 mm Hg and CAD, but did show a significant correlation of age with presence of both PAD and CAD. Further research that focuses specifically on women is needed and should include a larger sample, additional unique cardiovascular risk factors, and innovative diagnostic tests to determine presence of CAD in women early in the disease process.

Ankle foot orthoses (AFOs) are used to improve walking in some lower extremity conditions but AFOs restrict ankle motion resulting in a trade-off in ankle and hip mechanics. While the use of AFOs have been well documented, there still remain gaps in the literature. The first study compared the differences in sagittal plane ankle and hip kinematics and kinetics across three conditions at two speeds in healthy individuals while the second study compared frontal plane kinetics at the hip and knee and vertical ground reaction forces between two conditions at two speeds in healthy individuals. This was studied by collecting and analyzing three-dimensional joint kinematics and ground reaction forces from twelve healthy adults. Participants walked in three conditions (shod; i.e. athletic shoes only and two reduced push-off conditions using solid ankle foot orthoses (SAFOs); i.e. unilateral brace and bilateral brace conditions) and at two speeds (1.25m/s and 1.5m/s). In the first study, generalized linear models with general estimating equations were used to compare ankle and hip angles, moments and power for the braced and unbraced sides separately in all three conditions. In the second study, frontal plane kinetics and vertical ground reaction forces in the unbraced limb in the unilateral brace condition were compared to the same side during shod walking using paired sample t-tests. From our first study we found that the reduced push-off from the use of SAFOs results in decreased peak plantarflexion angles and power generation at the ankle and increased peak flexion angles, and first and second peak power generation at the hip in the braced limbs in both unilateral (p≤0.05) and bilateral (p≤0.05) brace conditions at both speeds. On the unbraced side in the unilateral brace condition, there were decreased peak power generation at the ankle at 1.25m/s and increased peak extension moments, first and second peak power generation at the hip compared to the shod condition (p<0.05) at both speeds. In the comparison between the unilateral and bilateral brace conditions, the changes in ankle and hip mechanics were similar to the changes between the shod condition and the bilateral brace condition on the unbraced side; in addition, participants also had higher peak extension moments in the unilateral brace condition compared to the bilateral brace condition (p<0.05). On the braced side, participants had lower peak plantarflexion moments at the ankle and lower peak flexion angles at the hip when walking with bilateral SAFOs, compared to walking with unilateral SAFOs (p<0.05). In the second study, we found that peak internal knee and hip abduction moments were 3% and 4% higher, respectively, in the unbraced limb in the unilateral brace condition at 1.25m/s (p≤0.041) compared to the same side in the shod condition. Peak vertical ground reaction force was 3% higher in the unbraced limb in the unilateral brace condition at both speeds (p=0.002). Findings indicate that walking with unilateral ankle foot orthoses presents an increased risk of developing secondary conditions.

Yes / The mechanical output at the ankle provides key contribution to everyday activities, particularly step/stair ascent and descent. Age-related decline in ankle functioning can lead to an increased risk of falls on steps and stairs. The rising up-on-the-toes (UTT) 30-second test (UTT-30) is used in the clinical assessment of ankle muscle strength/function and endurance; the main outcome being how many repetitive UTT movements are completed. This preliminary study describes how inertial measurement units (IMUs) can be used to assess the UTT-30. Twenty adults (26.2 ± 7.7 years) performed a UTT-30 at a comfortable speed, with IMUs attached to the dorsal aspect of each foot. Use of IMUs’ angular velocity signal to detect the peak plantarflexion angular velocity (p-fAngVelpeak) associated with each repeated UTT movement indicated the number of UTT movements attempted by each participant. Any UTT movements that were performed with a p-fAngVelpeak 2SD below the mean were deemed to have not been completed over a sufficiently ‘full’ range. Findings highlight that use of IMUs can provide valid assessment of the UTT 30-second test. Their use detected the same number of attempted UTT movements as that observed by a researcher (average difference, -0.1 CI, -0.2 – 0.1), and on average 97.6 ± 3.1% of these movements were deemed to have been completed ‘fully’. We discuss the limitations of our approach for identifying the movements not completed fully, and how assessing the consistency in the magnitude of the repeated p-fAngVelpeak could be undertaken and what this would indicate about UTT-30 performance.

The foot/ankle complex (particularly the hindfoot) is frequently injured in a wide array of debilitating events, such as car crashes. Numerical models have been used to assess injury risk, but most are minimally validated and do not account for variations in ankle posture that frequently occur during these events. The purpose of this study was to develop an accurate finite element (FE) model of the foot and ankle that accounts for these positional changes. The bone positions and load path in the foot and ankle were quantified throughout its natural range of motion. CT scans were taken of a male cadaveric leg in five postures in which fractures are commonly reported, while strains were recorded by strain gauges attached to the hindfoot bones in response to quasi-static, sub-failure loading. Substantial variations in bone displacements, rotations and strains were observed for all postures tested, highlighting the need for an FE model that accounts for these positional changes. The CT scans were used as the basis of an FE model of the foot and ankle that was developed using TrueGrid® and LS-Dyna® software. The model met rigorous mesh quality criteria, and its properties were optimized to best represent the experimental plantar tissue compression and surface strains. The model was evaluated by comparing its bone position and strain responses to the experimental results in each posture. The fracture thresholds and locations in each posture were estimated and were similar to those reported in the literature. The least vulnerable posture was neutral, and the talus and calcaneus exhibited the lowest fracture thresholds in all postures. This work will be useful in developing improved injury limits for the ankle and postural guidelines to minimize injury. The model can be used to evaluate new protective systems to reduce the occurrence of lower leg injuries. / Thesis / Master of Applied Science (MASc) / Ankle fractures are common occurrences that can lead to severe disability. Safety evaluations of the lower leg are often performed using computer models in a neutral ankle posture, which may underestimate the fracture tolerance in altered postures. The purpose of this study was to develop a computer model of the ankle that accounts for these changes. A cadaveric leg was used to determine how the locations of and strains in the bones of the foot and ankle varied as ankle posture was adjusted. A computer model of the lower leg and ankle was developed, and its accuracy was evaluated by comparison with the experimental results. The least vulnerable posture was neutral, and the hindfoot bones were the most likely to experience fracture in all postures. This model can be used in the future to evaluate new protective systems and develop comprehensive injury criteria for these altered postures.

Patients with a history of lateral ankle sprain (LAS) may experience different levels of mechanical and/or sensorimotor deficits following their injuries. Although various factors, such as structural damage, sensorimotor adaptation, perceived instability, swelling and/or pain, can develop and perpetuate the condition of chronic ankle instability (CAI), most previous CAI research on biomechanics has considered all patients with CAI as a homogeneous group. Recent research has clustered patients with CAI into six distinct movement patterns during a maximal jump-landing/cutting task. This approach could motivate clinicians to develop appropriate rehabilitation programs for each patient with CAI depending on their movement patterns. However, evaluating patients with CAI for the quality of movement and sensorimotor deficits using a 3D motion capture system and a force plate is not easily accessible in clinical settings. PURPOSE: (i) to identify subgroups within the CAI population based on their movement patterns using inertial measurement unit (IMU) devices and (ii) to characterize each subgroup's functional movement patterns during maximal jump-landing/cutting relative to the uninjured controls. METHODS: A total of 100 patients with CAI (height = 1.76 ± 0.1 m, mass = 74.0 ± 14.9 kg) were assessed according to the Foot and Ankle Ability Measure (FAAM) (ADL: 84.3 ± 7.6%, Sport: 63.6 ± 8.6%) and the Ankle Instability Instrument (AII) (6.7 ± 1.2) and were fit into clusters based on their movement strategy during the maximal jump-landing/cutting task. A total of 21 uninjured controls (height = 1.74 ± 0.1 m, mass = 70.7 ± 13.4 kg) were compared with each cluster. Seven IMU sensors were placed on the base of the lumbar spine, lower and upper legs, and feet and participants performed 5 trials of the maximal jump-landing/cutting test. Joint kinematics in the lower extremity were collected during the task using IMU sensors. Data were reduced to functional curves; kinematic data from the sagittal and frontal planes were reduced to a single representative curve for each plane. Then, representative curves were clustered using a Bayesian clustering technique. Functional analyses of variance were used to identify between-group differences for outcome measures and describe specific movement characteristics of each subgroup. Pairwise comparison functions as well as 95% confidence interval (CI) bands were plotted to determine specific differences. If 95% CI bands did not cross the zero line, we considered the difference significant. RESULTS: Four distinct clusters were identified from the sagittal- and frontal-plane kinematic data. Specific movement patterns in each cluster compared to either uninjured controls or rest of patients with CAI were also identified. CONCLUSION: The IMUs were able to distinguish 4 clusters within the CAI population based on distinct movement patterns during a maximal jump-landing/cutting task. Thus, IMUs can be effective measuring devices to distinguish and characterize multiple distinct movement patterns without relying on a traditional 3D motion capture system. Clinicians should consider utilizing IMU devices to measure and evaluate specific movement patterns in the CAI population during multiplanar demanding tests before developing appropriate treatment interventions in clinical settings.

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