Step Time Research Articles

Gait Variability is Related to Pain Interference in Children with Hypermobility Spectrum Disorder and Hypermobile Ehlers-Danlos Syndrome

<h3>Research Objectives</h3> To examine the relationship between variability of gait spatiotemporal parameters and pain interference in children with hypermobile spectrum disorder/hypermobile Ehlers-Danlos syndrome (HSD/hEDS). <h3>Design</h3> Cross-sectional, prospective study. <h3>Setting</h3> Movement Analysis for Biomedical Innovation and Technology (Mobility) Lab at the University of Wisconsin-Milwaukee, Milwaukee, WI. <h3>Participants</h3> Thirteen children with HSD/hEDS; 3 males, 10 females; 14.2 ± 2.9 years of age, body mass index: 22.0 ± 6.4 kg/m2. <h3>Interventions</h3> Not applicable. <h3>Main Outcome Measures</h3> Coefficient of variation (CV) was used to represent the variability of gait (CV = standard deviation (SD)/mean*100). The CV of step time, step length, gait speed, and cadence from five gait cycles were calculated. CV value greater than 3 SD from the mean was excluded from the analysis. The Brief Pain Inventory interference items related to daily activities (i.e., general activity, mobility, and going to school) were analyzed using a 0-10 scale where 0 is no interference and 10 is complete interference. Associations between gait variability and pain interference scores were analyzed using Pearson's correlation (r). <h3>Results</h3> The participants had CV of step time (n=12, 5.2 ± 9.5 CV%), step length (n=13, 5.5 ± 4.2 CV%), gait speed (n=13, 4.8 ± 2.5 CV%), and cadence (n=12, 5.7 ± 10.2 CV%). Brief Pain Inventory scores comprised general activity (2.5 ± 1.9), mobility (3.4 ± 2.0), and school (2.1 ± 2.8). Greater step length variability was moderately to strongly associated with greater pain interference with general activity (r=0.65, p=0.016), mobility (r=0.61, p=0.026), and going to school (r=0.78, p=0.003). <h3>Conclusions</h3> Increased gait variability was significantly correlated to pain interference during functional activities in children with HSD/hEDS. The variability may be due to altered muscle activation, disrupted proprioceptive feedback, and the instinct to protect from injury and provocative pain. Alterations in gait parameters and increased pain interference may reduce the quality of life. Future studies are needed to examine the mechanisms contributing to gait variability to guide patient-specific interventions for children with HSD/hEDS. <h3>Author(s) Disclosures</h3> The authors have no conflicts of interest to disclose.

A model predictive control regulation model for radiant air conditioning system based on delay time

Radiant air conditioning (RAC) systems are widely used because of the advantage of higher thermal comfort compared to convection systems. However, RAC systems exhibit considerable hysteresis and significant time delays in heat transmission from the terminal to the interior environment. Traditional feedback control methods do not adequately account for the system's delay impact while implementing dynamic control, resulting in a mismatch between supply and demand loads in time series, an inefficient impact of interior temperature control, and energy waste. According to this study, the time-delay characteristics of the RAC system are quantified by the startup-process delay time (SPDT) and operating-phase integrated delay time (IDT). The system startup time is set by the SPDT. Based on the IDT, the prediction interval of the model predictive control (MPC) and the step time of rolling optimization are determined. On this basis, a short-term forecasting model of air conditioning operating load and the regulation model of the system using MPC are established and verified by comparing with the conventional rule-based control of constant water temperature (CRBC) and proportionally-integral-differential (PID) control. The results for the RAC system with a large time delay indicate that the stability of indoor temperature under MPC controlling is 18.8% higher than the PID control and 63.5% higher than the CRBC method. Also, the indoor temperature controlled by the MPC is closest to the set value and shows the minimum fluctuation. Furthermore, the overall energy consumption of the system is estimated for reducing by 14.89% in comparison with the CRBC and by 8.51% in comparison with the PID.

선별적 집중 전신전기자극 훈련이 요추 불안정 대상자들의 요추 안정성 및 보행기능에 미치는 효과 : 무작위 맹검 대조군 연구

The purpose of this study was to identify the effects of selective intensive Whole-body electromyostimulation(WB-EMS) training on the lumbar stability, and gait function of subjects with lumbar instability. There were recruited 34 subjects with lumbar instability for this study. They were selected to have tested positive through the prone instability test and passive lumbar extension test. They were randomly divided into experimental group (n=17) with WB-EMS and control group (n=17) without WB-EMS, respectively. Both groups received a total of 45 minutes of intervention programs, respectively. Measurements were used before and after the intervention. The lumbar instability was measured by the single limb stance test and plank test. The gait function was used the gait analysis. The following statistical analysis was performed: an independent t-test for the general characteristics of the subjects, 2×2 analysis of variance with repeated measures for the lumbar instability and gait function. The group×time interaction effect showed significant improvement in the right single limb stance (F=5.445, p=.026), left single limb stance (F=4.245, p=.048) and plank test (F=4.341, p=.045) in lumbar stability test, And also, velocity (F=4.360, p=.045), cadence( F=4.681, p=.038), step time (F=5.261, p=.029) and step length (F=20.149, p=.000) of gait analysis. This study suggest that WB-EMS may be effective exercise for the lumbar stability and gait function in subjects with lumbar instability.

A step-by-step approach to a frozen pelvis

To demonstrate a step-by-step approach for restoration of pelvic anatomy in frozen pelvis using a systematic approach to make the steps reproducible, safe, and time efficient. Video presentation. Academic medical center. A 30-year-old nulliparous woman with lifelong dysmenorrhea and 4 years of infertility who presented for the surgical management of stage IV endometriosis. An abdominopelvic survey was first in a systematic fashion to assess the extent of adhesive disease and evalaute for normal anatomy. Dissection was then started on the patient's left side to mobilize the sigmoid colon at the pelvic brim. Subsequently, the ureters were identified and bilateral ureterolysis was performed as the retroperitoneal spaces were explored. Once the ureters were safely dissected, the adnexa were mobilized bilaterally. Attention was then turned to the dissection of the medial pararectal spaces (Okabayashi's space) before the dissection of the rectovaginal space. With the restoration of anatomy, the remaining planned surgery was completed. Restoration of pelvic anatomy, excision of endometriosis, and resolution of symptoms. The patient had an uncomplicated procedure with complete excision of endometriosis and an estimated blood loss of 45 mL. She was discharged on the same day and had an uneventful postoperative period. At her follow-up appointment, she had resolution of symptoms and was initiated on medical hormone suppression therapy until ready for invitro fertilization. A frozen pelvis is a condition in which the pelvic organs are distorted and tethered to each other as a result of adhesive processes. This can obscure normal anatomical landmarks and surgical planes making dissection extremely difficult, thus increasing the risk of interoperative and postoperative complications. Although an uncommon surgical condition, it is not rare to come across in clinical practices, thus creating a challenge to reproductive surgeons as it is commonly seen with endometriosis-associated infertility. It is important for surgeons to be able to recognize the relevant anatomy and have the knowledge to open proper pelvic avascular spaces in the pelvis to mitigate these risks. Following this video's step-by-step approach can help restore pelvic anatomy for planned surgical procedures.

Smartphone-based gait and balance accelerometry is sensitive to age and correlates with clinical and kinematic data

BackgroundThe Gait&Balance (G&B) App has produced valid and reliable measures of gait and balance in young healthy adults but has not been tested in older adults. Research questionIn healthy middle-to-older aged adults, are G&B App measurements sensitive to age, valid against clinical and kinematic measures, and reliable? MethodHealthy participants (n = 34, 14 male, 42–94 years) completed the G&B App protocol three times within a single session. 3D kinematics were collected concurrently. Clinical balance measures were collected (Modified Clinical Test of Sensory Interaction in Balance (mCTSIB), Mini Balance Evaluation Systems Test (MBT), and Functional Gait Assessment (FGA)). Sensitivity to age was assessed with Pearson’s correlations. Validity tests included Pearson’s correlations and Bland-Altman limits of agreement. Reliability tests included intra-class correlation coefficients and standard error of the measure. ResultsDuring quiet stance on a compliant surface, the G&B App was sensitive to age-related differences not detectable with the mCTSIB. During walking tasks, there was adequate convergent validity between the MBT and G&B App measures of step length, and between the FGA and G&B App measures of walking speed, step length, and periodicity. The G&B App had moderate-to-excellent validity against 3D kinematics for postural stability during quiet stance (r 0.98 [0.98, 0.99]), step time (r 0.97 [0.96, 0.98]), walking speed (r 0.79 [0.7, 0.86]), and step length (r 0.73 [0.61, 0.81]). Test-retest reliability was moderate-to-excellent for G&B App measures of postural stability, walking speed, periodicity, step length, and step time. G&B App measures of step length asymmetry, step length variability, step time asymmetry, and step time variability had poor validity and reliability. SignificanceThe G&B App was sensitive to age-related differences in balance not detectable with clinical measurement. It provides valid and reliable measures of postural stability, step length, step time, and periodicity, which are not currently available in standard practice.

Age-related changes in gait domains: Results from the LonGenity study

BackgroundImpairment in gait domains such as pace, rhythm, and variability are associated with falls, cognitive decline, and dementia. However, the longitudinal changes in these gait domains are poorly understood. The aim of this study was to examine age-related changes in gait domains overall and in those with cognitive impairment and mobility disability. MethodsParticipants were from the LonGenity study (n = 797; M Age=75.1 SD 6.5 years; 58.2% female) and were followed up to 12 years (Median=3.3; IQR: 1.1; 6.3). Gait speed and absolute values of step length, step time, cadence and, variability (standard deviation) of step length and step time during usual pace walking were assessed. Principal components analysis was used to obtain weighted combinations of three gait domains: pace (velocity, step length), variability (step length variability, step time variability) and rhythm (step time). Linear mixed effect models were used to examine age-related changes in gait domains overall, and in those with cognitive impairment and mobility disability at baseline. ResultsPace declined, and rhythm increased (worsened) in an accelerating non-linear fashion. Variability gradually increased with age. Those with cognitive impairment had faster rates of change in pace and rhythm. Those with mobility disability had faster increases in rhythm. ConclusionsAge-related changes in gait domains are not uniform. Individuals with cognitive and mobility impairments are particularly vulnerable to accelerated change in pace and or rhythm.

Gait variability predicts cognitive impairment in older adults with subclinical cerebral small vessel disease.

Advanced methods of gait research, including approaches to quantify variability, and orderliness/regularity/predictability, are increasingly used to identify patients at risk for the development of cognitive impairment. Cerebral small vessel disease (CSVD) is highly prevalent in older adults and is known to contribute to the development of vascular cognitive impairment and dementia (VCID). Studies in preclinical models demonstrate that subclinical alterations precede CSVD-related cognitive impairment in gait coordination. In humans, CSVD also associates with gait abnormalities. The present study was designed to test the hypothesis that increased gait variability and gait asymmetry predict a decline in cognitive performance in older adults with CSVD. To test this hypothesis, we compared cognitive performance and gait function in patients with CSVD (age: 69.8 ± 5.3 years; n = 11) and age- and sex-matched control participants (age: 70.7 ± 5.8 years; n = 11). Based on imaging findings, patients with CSVD were identified [presence of white matter hyperintensities plus silent brain infarcts and/or microhemorrhages on magnetic resonance imaging (MRI) assessment]. Cognitive performance was assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB). Gait parameters were measured during the single and dual tasks, during which participants, in addition to the motor task, completed a series of mental arithmetic calculations. Spatial and temporal parameters of gait variability, symmetry, and permutation entropy were determined using a pressure-sensitive gait mat during single and dual cognitive task conditions. Patients with CSVD exhibited lower performance in a visual learning test (p = 0.030) and in a sustained attention test (p = 0.007). CSVD also affected step time variability (p = 0.009) and step length variability (p = 0.017). Step lengths of CSVD participants were more asymmetric (p = 0.043) than that of controls, while the two groups were statistically similar regarding step time symmetry and entropy of step time and length. Gait variability was inversely associated with sustained attention, especially among CSVD patients, and this relationship was significantly different between the two groups. The association of sustained attention with gait symmetry was also significantly different between the two groups. Our findings provide additional evidence in support of the concept that increased gait variability and asymmetry may predict cognitive impairment in older adults with CSVD.

Improving real-time energy decision-making model with an actor-critic agent in modern microgrids with energy storage devices

The hereby study combines a reinforcement learning machine and a myopic optimization model to improve the real-time energy decisions in microgrids with renewable sources and energy storage devices. The reinforcement learning-based agent is built as an actor-critic agent making the aggregated near-optimal charging/discharging energy decisions of the microgrid energy storage devices from a discrete action space relying on a reward related to the microgrid online optimal objective function value. The next step time energy levels of storage devices are then computed and provided to the myopic optimization-based decision-making model as parameters which optimally find the incurred power flow within the microgrid minimizing the real-time microgrid energy cost. The real-time measurement of stochastic parameters of the microgrid coupled with the current energy levels of electrical and heat storage are input to the artificially intelligent machine as observations states. The actor-critic agent approximators are modeled as deep neural networks optimized using the Adam gradient descent algorithm with a gradient threshold. Although the proposed model with a 2-kWh increment of the charging/discharging energy training is time-consuming, it has been able at 100% to optimally make microgrid energy decisions and improve online energy decisions by 90.98% compared to the myopic model alone.

Reducing cost of transport in asymmetrical gaits: lessons from unilateral skipping.

Unilateral skipping is an asymmetrical gait only exceptionally used by humans, due to high energetic demands. In skipping, the cost of transport decreases as speed increases, and the spring-mass model coexists with the vaulting pendular one. However, the mechanisms of energy transfers and recovery between the vaulting and the bouncing steps are still unclear in this gait. The objective of this work is to study how spatiotemporal and spring-mass asymmetries impact on metabolic cost, lowering it despite speed augmentation. Kinematics and metabolic rates of healthy subjects were measured during running and skipping on a treadmill at controlled speeds. Metabolic power in skipping and running increased with similar slope but different intercepts. This fact determined the different behaviour of the cost of transport: constant in running, decreasing in skipping. In skipping the step time asymmetry remained constant, while the step length asymmetry decreased with speed, almost disappearing at 2.5m/s-1. Leg stiffness in trailing limb increased with higher slope than in leading limb and running; however, the relative leg stiffness asymmetry remained constant. Slow skipping presents short bouncing steps, even shorter than the vaulting, impacting the stride mechanics and the metabolic cost. Faster speeds were achieved by taking longer bouncing steps and a stiffer trailing limb, allowing to improve the effectiveness of the spring-mass mechanism. The step asymmetries' trends with respect to speed in skipping open the possibility to use this gait as an experimental paradigm to study mechanisms of metabolic cost reduction in locomotion.

A self‐stabilised walking gait for humanoid robots based on the essential model with internal states

AbstractWalking stability is one of the key issues for humanoid robots. A self‐stabilised walking gait for a full dynamic model of humanoid robots is proposed. For simplified models, that is, the linear inverted pendulum model and variable‐length inverted pendulum model, self‐stabilisation of walking gait can be obtained if virtual constraints are properly defined. This result is extended to the full dynamic model of humanoid robots by using an essential dynamic model, which is developed based on the zero dynamics concept. With the proposed method, a robust stable walking for a humanoid robot is achieved by adjusting the step timing and landing position of the swing foot automatically, following its intrinsic dynamic characteristics. This exempts the robot from the time‐consuming high‐level control approaches, especially when a full dynamic model is applied. How different walking patterns/features (i.e., the swing foot motion, the vertical centre of mass motion, the switching manifold configuration, etc.) affect the stability of the walking gait is analysed. Simulations are conducted on robots Romeo and TALOS to support the results.

Single subject analysis of individual responses to prosthetic modifications based on passive dynamic walking model

BackgroundGroup statistical analysis may mask individual differences in response to interaction with rehabilitative devices such as prostheses. This study sets out to evaluate the effect of asymmetric prosthesis using a single subject methodology on individuals with unilateral transfemoral amputation. MethodsAcceleration data of 17 participants with unilateral transfemoral amputation were collected using a triaxial accelerometer attached at the L3 level of the spine during level ground walking under four prosthesis conditions: 1) no added mass; 2) the knee joint relocated downwards by 18% of the total shank length, shank mass decreased by 68%, thigh mass increased by 7%; 3) the knee joint relocated downwards by 37% of the total shank length, shank mass decreased by 68%, thigh mass increased by 7%, and 4) thigh mass increased 17%, shank mass decreased by 38%. Step length, step time, step length variability, step time variability and Floquet multiplier were statistically assessed. FindingsThe single subject analysis highlighted that under prosthetic modifications, intact limb step length was increased and prosthetic step length was deceased in most participants (n > 9). No significant changes were observed in Floquet multiplier (n > 14), step length (n > 6) and step time variability (n > 9) across all conditions. InterpretationSingle subject analysis showed that in response to the immediate effect of asymmetric prosthesis, increase in the intact limb step length and decrease in the prosthetic limb step length emerged as a dominant strategy for most participants. Regarding Floquet multiplier, step length, and step time variability, our prosthetic modifications did not produce the anticipated effects.

Effects of age, sex, frailty and falls on cognitive and motor performance during dual-task walking in older adults

BackgroundDual-task (DT) walking is of great interest in clinical evaluation to evaluate the risk of falling or cognitive declines in older adults. However, it appears necessary to investigate deeply the confounding factors to better understand their impact on dual-task performance. ObjectiveTo evaluate the effect of age, sex, falls and frailty on cognitive and motor parameters in dual-task walking. Subjects66 older participants (mean age = 75.5 ± 6.3; mean height = 165.8 ± 8.4 cm; mean weight = 68.4 ± 14 kgs) were split into groups based on their age, sex, fall and frailty status. MethodsParticipants performed single-task walking, single-task cognitive (serial subtraction of 3), and dual-task walking (subtraction + walking) for 1 min at their fast pace. Gait speed, step length, step length variability, stance and swing phase time, single and double support, cadence, step time variability and gait speed variability were recorded in single- and dual-task walking and used to calculate the dual-task effect (DTE) as ((DT − ST) / ST) ∗ 100). The cognitive score (DTEcog) was calculated as the number of correct responses minus errors. Generalized linear mixed models (GLMM) were used to compare the effects of falls, frailty, age and sex on gait and cognitive variables. ResultsThe interaction frailty*sex and frailty*age were the major effect on the DTEs. Specifically, the DTE was higher in women than men and in the frail group compared to non-frail. ConclusionsThe present findings provide a better understanding on the confounding factors explaining the behavior in DT that could be used to develop more effective dual-task clinical programs for community-living older adults.

Footstep adjustment for biped push recovery on slippery surfaces

Despite extensive studies on motion stabilization of bipeds, they still suffer from the lack of disturbance coping capability on slippery surfaces. In this paper, a novel controller for stabilizing a bipedal motion in its sagittal plane is developed with regard to the surface friction limitations. By taking into account the physical limitation of the surface in the stabilization trend, a more advanced level of reliability is achieved that provides higher functionalities such as push recovery on low-friction surfaces and prevents the stabilizer from overreacting. The discrete event-based strategy consists of modifying the step length and time period at the beginning of each footstep in order to reestablish stability necessary conditions while taking into account the surface friction limitation as a constraint to prevent slippage. Adjusting footsteps to prevent slippage in confronting external disturbances is perceived as a novel strategy for keeping stability, quite similar to human reaction. The developed methodology consists of rough closed-form solutions utilizing elementary math operations for obtaining the control inputs, allowing to reach a balance between convergence and computational cost, which is quite suitable for real-time operations even with modest computational hardware. Several numerical simulations, including push recovery and switching between different gates on low-friction surfaces, are performed to demonstrate the effectiveness of the proposed controller. In correlation with human-gait experience, the results also reveal some physical aspects favoring stability and the fact of switching between gaits to reduce the risk of falling in confronting different conditions.

PHSOR11 Presentation Time: 1:20 PM: Verify the Transit Time Correction Accuracy of the Bravos Afterloader System Using a Novel Scintillation-Based Brachytherapy Quality Assurance Device

<h3>Purpose</h3> Compared to the older generations, the new Bravos high dose rate (HDR) afterloader offers the function to automatically correct dwell time to compensate the transit dose effect. To our best knowledge, there is no QA attempt to verify the accuracy of this correction. To address this issue, a new transit time measurement module has been developed and included in the OriQA HDR QA device, an autonomous phantom for HDR brachytherapy quality assurance. In this work, we employ the OriQA system to verify the transit time correction accuracy of the Bravos afterloader system. <h3>Method</h3> The OriQA device utilizes radioluminescence imaging technique to accurately measure HDR source strength, dwell time, and dwell position. It consists of a 20 cm needle applicator insert, a radioluminescence phosphor sheet placed directly atop the applicator, a digital camera, and software for signal processing and displaying results. Radiation-induced luminescence photons are emitted from the phosphor sheet and captured by the camera. The signal intensity and location are processed to yield relative source strength and dwell information. For the verification test, one of the Bravos channels was connected to the OriQA applicator using a one-meter transfer tube. After specific plan delivery, the raw data of OriQA measurement including source position and time was exported to Matlab for further analysis. The real dwell time at each dwell position and the transit time between dwells during cable extension and retraction were extracted. The transit time correction method provided by the vendor was applied to the measurement, yielding the delivered dwell time. The percentage difference between the delivered and planned dwell time was calculated and used as an indicator of the transit time correction accuracy. Several verification plans were created including seven with fixed dwell steps, one with variable dwell steps, and one with variable dwell time. Plans with fixed dwell steps were delivered three times. The rest were delivered once. Plan details are listed in table 1. For each plan, the mean and standard deviation of the difference between planned and delivered dwell time were calculated from all dwell positions and deliveries. <h3>Results</h3> The deviations between the planned and delivered dwell time are listed in table 1. For plans with less than 4 cm dwell step, the accuracy of transit time correction is, on average, less than 1.2% of the dwell time. For plans with 4 cm and 9 cm dwell step, the accuracy is 1.5% and 2.85%, on average, respectively. Dwell time variation does not affect the correction accuracy, as shown in plan 9. Standard deviations of plan 3, 4, and 9 are greater than 1% due to the relatively large difference at the proximal dwell. <h3>Conclusion</h3> This is the first study that successfully verifies the transit time correction accuracy of the Bravos system. Less than 2% accuracy is observed for clinically relevant dwell steps (0.3 cm to 4 cm). Variations in dwell step, dwell position, and dwell time do not worsen the accuracy.

The Effect of Resist and Assist Torque of Hip Joint Motor-based Gait Assistance Robot on Gait Function in the Elderly

OBJECTIVES The purpose of this study was to investigate the effects of assist and resistance torque on the spatiotemporal gait characteristics, and the symmetry and asymmetry of gait using a Gait Enhancing and Motivating System (GEMS) in the elderly.METHODS A cross-sectional and repeated measure design was used. A total of 18 participants (9 males, 9 females; age: 63.5 ± 5.02 years; mass: 64.26 ± 6.87 kg; height: 164.06 ± 7.15 cm) were recruited from a local community, and spatiotemporal gait data were collected with OptoGait system and GEMS. Spatiotemporal gait variables and differences between the dominant and non-dominant legs of these variables were assessed (step length, step time, stance phase, swing phase, single support, load response, pre swing phase, stride time, stride length, double support, cadence, and gait speed). The effects of three modes including normal, assist, and resist modes using GEMS were investigated twice for each participant on a 9-meter walkway. A one-way repeated measure analysis of variance followed by Bonferroni post-hoc tests was conducted.RESULTS The assist mode increased step time, swing phase, stride time and reduced stance phase, pre-swing phase, double support, cadence, and gait speed as compared to normal mode. The resist mode increased stance phase, load response, pre-swing phase, double support, cadence, and reduced step time, swing phase, and stride time. In dominant leg, assist mode showed increased step time and reduced pre-swing phase than normal mode, and greater step time than resist mode (&lt;i&gt;p&lt;/i&gt; &lt; 0.05). However, there was no effect of external torque on symmetry and asymmetry between both legs (&lt;i&gt;p&lt;/i&gt; &gt; 0.05).CONCLUSIONS The resistance and assist torque of GEMS alter spatiotemporal characteristics during the stance and swing phase of gait in the elderly. However, the resistance torque and assist torque of GEMS did not increase or decrease the gait asymmetry between the dominant and non-dominant legs.

Study of the differences in the gait parameters of healthy and diseased limbs in patients with knee osteoarthritis

Knee osteoarthritis is a prevalent condition that affects millions of people worldwide. It is a degenerative disease that occurs when the protective cartilage in the knee joint wears down over time, leading to pain, stiffness, and swelling in the knee. The actuality of knee osteoarthritis lies in its high prevalence, significant healthcare costs, and impact on quality of life. The article presents the results of the study of the difference in gait parameters of healthy and diseased limbs in patients with knee osteoarthritis. Twenty patients were examined. The diagnosis of knee osteoarthritis was established according to the criteria of the American College of Rheumatology. Gait parameters were studied using the GAITRite® system. The following parameters were studied: Temporal Definitions (Step Time, Gait Cycle Time, Single Support, Initial Double Support, Stance); Spatial Parameters and Definitions (Step Length, Stride Length, H-H Base of Support, Toe In / Toe Out). Among the investigated indicators, two demonstrated reliable differences between healthy and diseased limbs. It was found that Step Time for diseased limb was statistically significantly greater than for the opposite limb. At the same time, the foot support time of the healthy limb and, accordingly, the Initial Double Support indicator statistically significantly exceeded the similar indicators for the diseased limb. Summarizing the results of еру study, it can be stated that patients with knee osteoarthritis have a gait disorder in the form of asymmetric steps. Thus, the time of support on the foot decreases, and accordingly, the time of transferring the foot of the diseased limb increases. Changes in the diseased limb are also reflected in the opposite, healthy limb. An effort to increase the speed of movement during the examination causes an increase in movement on a relatively healthy limb in the form of an increase in the length of the step and a reduction in the time of transfer of the foot of the diseased limb. Keywords: knee joint; osteoarthritis; gait parameters; GAITRite.

Determine the kinematics and kinetics parameters associated with bilateral gait patterns among healthy, overweight, and obese adults.

Biomechanical analysis of gait is important to obtain information regarding the lower limb impairments and dysfunction during locomotion. This study aimed to determine the potential difference among healthy, overweight, and obese participants and their impact on gait parameters by observing the kinematic and kinetics parameters. A cross-sectional study conducted with forty (15 healthy, 12, overweight, 13 obese) male participants. All participants were non-smokers, and their physical activity level was 7000±2142 steps per day. Participants anthropometric characteristics were age:21.57±1.46 years; height:173. 63±6.43 cm, body mass;86.15±23.36 kg., body mass index (BMI) :28.57±7.68 kg/m2, body fat:29.93±9.44%. A bioelectrical impedance device was used to determine participants' body composition and health status. A portable pressure sensor mat (Walkway) from Tekscan was used to measure bilateral gait parameters kinematically and kinetically. One-way analysis of variance was used to determine the differences between groups. Significant differences were found between health, overweight, and obese participant for different bilateral gait's kinematic and kinetic parameters as cadence, gait velocity, step time, step length, step velocity, step width, stride time, stride length, stride velocity, maximum force, maximum peak pressure, active propulsion, and passive propulsion except impulse at .05 level of significance. The findings shows that kinematics and kinetics parameters of gait were affected by the status of their BMI. Current research suggests that increased body weight interferes with normal musculoskeletal function via a range of kinematic and kinetic deficits. More research is required to accurately understand the structural and functional restriction imposed by overweight and obese individuals.

Changes in Key Biomechanical Parameters According to the Expertise Level in Runners at Different Running Speeds

Running has become increasingly popular worldwide. Among runners, there exists a wide range of expertise levels. Investigating the differences between runners at two extreme levels, that is novices and experts, is crucial to understand the changes that occur as a result of multiple years of training. Vertical oscillation of center of mass (CoM), stride frequency normalized to the leg length, and duty factor, which describes the step time relative to the flight time, are key biomechanical parameters that have been shown to be closely related to the running economy and are used to characterize the running style. The variability characteristics of these parameters may reveal valuable information concerning the control of human locomotion. However, how the expertise level and running speed affect the variability of these key biomechanical parameters has not yet been investigated. The aim of this study was to analyze the effects of expertise level (novice vs. expert) and running speed (10 km/h vs. 15 km/h) on these parameters and their variability. It was hypothesized that expert runners would have lower vertical oscillation of CoM, normalized stride frequency, and duty factor and show less variability in these parameters. The parameters' variability was operationalized by the coefficient of variation. The mean values and variability of these key biomechanical parameters according to expertise level and running speed were compared with rmANOVAs. The results showed that the experts had a lower duty factor and less variable vertical oscillation of CoM and normalized stride frequency, independently of the running speed. At a higher running speed, the variability of vertical oscillation of CoM was higher, whereas that of normalized stride frequency and duty factor did not change significantly. To the best of our knowledge, this is the first study analyzing the effects of expertise level and running speed on the variability of key biomechanical parameters.

Multidisciplinary Model of Cervical Cancer Management in Botswana: Benchmarking the Care Cascade to Identify the Impact of Delays

<h3>Purpose/Objective(s)</h3> Timely access to and completion of radiation therapy (RT) are crucial for optimizing clinical outcomes of patients with locally advanced cervical cancer. The cascade of cancer care comprises the steps between initial presentation and treatment initiation. It is unknown which of these steps if any contribute to delay and downstream survival. Multi-disciplinary management has been shown to enhance the likelihood of successful care coordination and delivery across this cascade, but when implemented in limited resource settings it is unknown if multi-disciplinary management initiatives can adequately identify care delivery gaps. This study sought to examine care delivery metrics and outcomes from a newly established multi-disciplinary team clinic (MDT) in a limited resource setting. The analysis benchmarked the timing of steps between diagnosis and RT initiation in patients with locally advanced cervical cancer in Botswana to determine if delay impacted survival. <h3>Materials/Methods</h3> Between January 2016 and July 2018, 230 patients with biopsy-proven cervical cancer were enrolled in Gaborone, Botswana and followed until November 2019. The number of days between biopsy, pathology, MDT consult, RT consult, simulation, and treatment start were calculated based on dates of care delivery. The association of delay with survival was evaluated using the Kaplan-Meier estimates and multivariable Cox proportional hazards models. <h3>Results</h3> After diagnosis, 187 (81.3%) patients ultimately received treatment. Times between various steps of the care cascade are detailed in Table 1. Untreated patients had a median of one-month additional delay between biopsy and pathology result (57 vs. 25 days, p=0.003). Univariate analysis showed patients treated with curative intent (EQD2 >65 Gy) had worse overall survival when delay between simulation and RT start was > 12 days (p=0.048). Median survival was 2 vs. 4.6 years for patients with and without delay >12 days, respectively. This association trended toward but did not meet statistical significance on multivariate analysis after controlling for HIV status and stage (HR 2.35, 95% CI 0.95 – 5.85, P=0.07). HIV status was not associated with delay at any point. <h3>Conclusion</h3> Treatment delay exists in all steps of the care cascade for patients with cervical cancer in Botswana. Delay of >12 days between radiation simulation and initiation was found to negatively impact survival in patients treated with curative intent. This study also demonstrates the feasibility of utilizing the resources of an MDT care model to quantify care delivery benchmarks in a low-resource setting, resulting in identification of actionable targets to improve care delivery and outcomes.

Functional connectivity of proximal and distal lower limb muscles and impact on gait variability in stroke

BackgroundHigher gait variability after stroke increases risk of falls and compromises safe community ambulation. Corticomotor connectivity plays an important role in walking after stroke, however, its relation to gait variability remains unknown. Research questionDo corticomotor characteristics of the proximal and distal lower limb muscles predict gait variability in individuals with chronic stroke? MethodsRetrospective analysis of data from 30 individuals with chronic stroke was conducted. Corticomotor characteristics were measured in the paretic and non-paretic tibialis anterior (TA, distal muscle) and rectus femoris (RF, proximal muscle) using transcranial magnetic stimulation. We calculated corticomotor excitability ratio of paretic TA and RF (CMETA/RF), corticomotor excitability symmetry (CMEsym) between hemispheres for the TA and RF, and ipsilateral corticomotor excitability (ICE) of the paretic TA. Gait variability was quantified as the coefficient of variation of the paretic step length (spatial) and step time (temporal) during comfortable walking. Relations between corticomotor characteristics and gait variability were tested with multiple linear regression. ResultsCMETA/RF and CMEsym of RF were significant predictors of spatial gait variability. Greater corticomotor input to the paretic RF compared to the paretic TA and greater symmetry of RF were related to higher spatial gait variability. There were no significant predictors of temporal gait variability. SignificanceCorticomotor inputs to the proximal RF may be important for spatial gait variability, reflecting a compensatory role of RF in walking after stroke. Stroke survivors with relatively greater corticomotor input to the paretic RF may adopt compensatory strategy to enhance propulsion and achieve foot clearance, but it may also increase spatial gait variability, particularly when combined with impaired motor control of the paretic TA. These findings may provide novel rehabilitative targets to decrease gait variability and promote safe ambulation in individuals with stroke.