Toe Off Research Articles

Dependence of Total Ankle Tibial Baseplate Stability Upon Device Fixation Features

Category: Ankle Arthritis Introduction/Purpose: Patient outcomes and construct longevity after total ankle replacement (TAR) are both linked to initial implant stability. Limited early micromotion between the implant and bone encourages stability. Tibial component design fixation features play a critical role in determining the initial stability, with retention of medial and lateral bone sidewalls and interference press-fit used to supplement fixation. The goal of this study was to characterize micromotion between the tibia and baseplate using finite element analysis (FEA) to determine how baseplate design features influence stability. Methods: Three commercially available TAR tibial component baseplate designs were virtually inserted into a computer model of the distal tibia of an end-stage ankle arthritis patient (Fig. 1a). Implant insertion was simulated using FEA for each tibial component with two different fixation cases: (1) no sidewalls+line-to-line fit and (2) sidewalls retained+50µm interference press-fit. Tibia models were derived from patient CT scans, with element-by-element material properties assigned based upon CT Hounsfield units. The tibial components were assigned titanium alloy properties. Following simulated implantation, FEA was performed using kinematic and kinetic profiles representing the stance phase of gait. Loads/moments scaled to patient body weight were applied to the implant (Fig. 1b, 1c), while the proximal tibia was held fixed. Micromotions were defined as the displacement difference between bone-implant closest nodal pairs, computed from FEA output using custom-written code. Results: Amongst tibial component designs inserted without sidewalls and with line-to-line fit, relatively large micromotions were observed. Micromotion differences at heel strike between Peg Designs 1 and 2 may be attributable to sidewall height, while Peg Design 3 was less susceptible to the proximal forces and dorsiflexion moments dominant in early stance (Fig. 1d), potentially because of its angled anterior pegs. Micromotions in Peg Design 3 were largest near toe off, where the plantarflexion moment and decreased proximal force may have permitted motion along the pegs. Differences in micromotion between the different implant designs over the stance phase of gait were greatly reduced when interference press-fit was modeled (Fig. 1e). Conclusion: This study provides new insight on the relative initial stability afforded by different TAR fixation features across designs. In the absence of interference press-fit, all designs showed micromotions large enough to be concerning. However, when interference press-fit was modeled, all designs performed similarly in terms of initial stability during simulated gait. While a better understanding of the relationships between TAR implant features, patient bone density profiles, and initial stability is still needed, our findings suggest that implant interference press-fit plays an important and dominant role in device performance.

Performance Level Affects Full Body Kinematics and Spatiotemporal Parameters in Trail Running-A Field Study.

Trail running is an emerging discipline with few studies performed in ecological conditions. The aim of this work was to investigate if and how biomechanics differ between more proficient (MP) and less proficient (LP) trail runners. Twenty participants (10 F) were recruited for a 9.1 km trail running time trial wearing inertial sensors. The MP athletes group was composed of the fastest five men and the fastest five women. Group differences in spatiotemporal parameters and leg stiffness were tested with the Mann-Whitney U-test. Group differences in joint angles were tested with statistic parametric mapping. The finish time was 51.1 ± 6.3 min for the MP athletes and 60.0 ± 5.5 min for the LP athletes (p < 0.05). Uphill sections: The MP athletes expressed a tendency to higher speed that was not significant (p > 0.05), achieved by combining higher step frequency and higher step length. They showed a tendency to shorter contact time, lower duty factor and longer flight time that was not significant (p > 0.05) as well as significantly lower knee flexion during the stance phase (p < 0.05). Downhill sections: The MP athletes achieved significantly higher speed (p < 0.05) through higher step length only. They showed significantly higher knee and hip flexion during the swing phase as well as higher trunk rotation and shoulder flexion during the stance phase (p < 0.05). No differences were found with respect to leg stiffness in the uphill or downhill sections (p > 0.05). In the uphill sections, the results suggest lower energy absorption and more favorable net mechanical work at the knee joint for the MP athletes. In the downhill sections, the results suggest that the more efficient motion of the swing leg in the MP athletes could increase momentum in the forward direction and full body center of mass' velocity at toe off, thus optimizing the propulsion phase.

Overhead squat assessment reflects treadmill running kinematics

PurposeOverhead squat assessment (OHSA) is a pre-activity dynamic movement analysis tool used to define deviations from an ideal motion pattern which known as compensation. Compensatory movements may result from abnormality in myofascial activity, length-tension relationships, neuro-motor control strategies, osteokinematics and arthrokinematics. The aim of this study is to identify the association between selected biomechanical variables of the ankle, knee, hip, pelvis, torso during OHSA and 16 km/h treadmill running tasks.MethodsThirteen national long distance male runners (17.3 ± 0.5 age (years); 5.89 ± 1.95 experience (years), 57.9 ± 3.7 body mass (kg); 175.4 ± 5.7 height (cm)) participated in this 2controlled laboratory study. Three-dimensional kinematics were collected at 250 Hz using a 9-camera Qualisys motion analysis system (Qualisys AB, Goteborg, Sweden) while participants performed 16 km/h treadmill running and OHSA tasks.ResultsCorrelation coefficients demonstrated that OHSA pelvic anterior tilt angle was in a positive association with foot strike (FS), mid-stance (MS), and toe-off (TO) pelvic anterior tilt angles and MS tibial internal rotation on talus, MS ankle pronation, MS hip internal rotation. OHSA pelvic anterior tilt angle was in a negative association with TO hip extension. OHSA maximal hip adduction was positively correlated with MS and stance maximal knee adduction. FS, MS, stance maximal angular dorsiflexion values were positively correlated with OHSA dorsiflexion. Increased OHSA dorsiflexion angle was negatively associated with TO plantar flexion. OHSA pronation was positively associated with MS and stance pronation. MS hip internal rotation, MS hip adduction angles were increased, and MS ankle dorsiflexion was significantly decreased with the increase of trunk forward lean relative to tibia during OHSA.ConclusionsOHSA was associated with some important and dysfunction-related hip, knee and ankle kinematics. Running coaches, may use OHSA as an assessment tool before the corrective training plan to detect injury-related compensation patterns to reduce the risk of injury and improve running technique.

Biomechanical Fundamentals of Hand Standing and Somersaults: The Impact of Coaching Interference

Biomechanics is the leading sports science concerned with movement technique. This is particularly significant in gymnastics, where the performance styles of the top gymnasts serve as examples for others to emulate, we aimed to conduct this study to evaluate the biomechanical fundamentals of hand standing and somersaulting between the two groups with and without coach interferences. A comparative study was conducted in which 24 highly competitive national standard healthy male gymnasts were enrolled. The participants were divided into two equal groups each group consisting of 12 players. One group was interfered and additionally trained by a coach and another group served as control in which there was no additional interference of coach. The researchers filmed the performance via canon EOS 100D cameras, while the motion analysis was done using the Kinovea motion analysis program. For hand standing, balance time and postural execution was observed between two groups. For somersault, c-motion guidelines were used to attach markers to the joints and limbs of participants to observe the angle and angular velocity of joints. A total of 24 participants (12 in each group) were analysed. Results was found out that the angles of ankle, knee, hip and shoulder at toe off time was found statistically significant. The angular velocity at the time of initial contact and toe off between the two groups was statistically significant. The hand standing between two groups was found son significant. The study results revealed that the angles of participant under coach interferences were found effective in somersault. In light of the results, it is recommended that joint angles should be focused to acquire this technique more effectively. Keywords: somersaults, hand standing, biomechanical fundamentals, coaching interference, gymnastic.

A Smartphone-Based sEMG Signal Analysis System for Human Action Recognition.

In lower-limb rehabilitation, human action recognition (HAR) technology can be introduced to analyze the surface electromyography (sEMG) signal generated by movements, which can provide an objective and accurate evaluation of the patient's action. To balance the long cycle required for rehabilitation and the inconvenient factors brought by wearing sEMG devices, a portable sEMG signal acquisition device was developed that can be used under daily scenarios. Additionally, a mobile application was developed to meet the demand for real-time monitoring and analysis of sEMG signals. This application can monitor data in real time and has functions such as plotting, filtering, storage, and action capture and recognition. To build the dataset required for the recognition model, six lower-limb motions were developed for rehabilitation (kick, toe off, heel off, toe off and heel up, step back and kick, and full gait). The sEMG segment and action label were combined for training a convolutional neural network (CNN) to achieve high-precision recognition performance for human lower-limb actions (with a maximum accuracy of 97.96% and recognition accuracy for all actions reaching over 97%). The results show that the smartphone-based sEMG analysis system proposed in this paper can provide reliable information for the clinical evaluation of lower-limb rehabilitation.

Effect of perturbation timing on recovering whole-body angular momentum during very slow walking

Humans prioritize regulation of the whole-body angular momentum (WBAM) during walking. When perturbed, modulations of the moment arm of the ground reaction force (GRF) with respect to the centre of mass (CoM) assist in recovering WBAM. For sagittal-plane perturbations of the WBAM given at toe off right (TOR), horizontal GRF modulations and not centre of pressure (COP) modulations were mainly responsible for these moment arm modulations. In this study, we aimed to find whether the instant of perturbations affects the contributions of the GRF and/or CoP modulations to the moment arm changes, in balance recovery during very slow walking. Perturbations of the WBAM were applied at three different instants of the gait cycle, namely at TOR, mid-swing (MS), and heel strike right (HSR). Forces equal to 16% of the participant’s body weight were applied simultaneously to the pelvis and upper body in opposite directions for a duration of 150 ms. The results showed that the perturbation onset did not significantly affect the GRF moment arm modulation. However, the contribution of both the CoP and GRF modulation to the moment arm changes did change depending on the perturbation instant. After perturbations resulting in a forward pitch of the trunk a larger contribution was present from the CoP modulation when perturbations were given at MS or HSR, compared to perturbations at TOR. After backward pitch perturbations given at MS and HSR the CoP modulation counteracted the moment arm required for WBAM recovery. Therefore a larger contribution from the horizontal GRF was needed to direct the GRF posterior to the CoM and recover WBAM. In conclusion, the onset of WBAM perturbations does not affect the moment arm modulation needed for WBAM recovery, while it does affect the way CoP and GRF modulation contribute to that recovery.

Gait Analysis, Metabolic Parameters and Adherence to the Mediterranean Diet in Patients with Type 2 Diabetes Mellitus Compared with Healthy Controls: A Pilot Study.

Patients with type 2 diabetes mellitus (T2DM) are prone to developing diabetic peripheral neuropathy (DPN) with an increased risk of injuries while walking, potentially leading to plantar ulcers. We aimed to assess the early gait changes in T2DM patients without clinical signs of DPN in comparison to age-matched healthy controls (HC). One hundred T2DM patients (78 women, mean age: 66.4 ± 11.5 years) and 50 age-matched HC (34 women, mean age 62.1 ± 7.9 years) were evaluated with the PODOSmart® gait analysis device. Anthropometric and biochemical data, as well as dietary habits were collected for all participants. T2DM patients also completed the Diabetes Distress (DS) self-report validated questionnaire. One patient was excluded from the study due to lack of recent biochemical data. Among the T2DM patients, 88.9% reported little or no DS and 11.1% moderate DS. The T2DM group had higher body mass index, waist circumference, systolic blood pressure, glycated hemoglobin A1c, sodium, white blood cell count, triglycerides and low-density lipoprotein cholesterol, but lower high-density lipoprotein cholesterol than HC (p < 0.05 for all comparisons). The MedDiet score was satisfactory in both groups (p > 0.05). Significant differences were found between the two study groups in gaitline heel off, propulsion speed, foot progression angle, time taligrade phase, stride length, walking speed, angle attack, oscillation speed, pronation-supination toe off and clearance. The T2DM patients without self-reported DS or clinical signs of DPN may exhibit significant differences in several gait parameters analyzed with PODOSmart®. Whether gait analysis can be used as an early diagnostic tool of T2DM complications should be further explored.

Standing Pelvic Tilt Is Associated With Dynamic Pelvic Tilt During Running When Measured by 3-Dimensional Motion Capture.

Standing pelvic tilt (PT) is related to biomechanics linked with increased risk of injury such as dynamic knee valgus. However, there is limited evidence on how standing PT relates to dynamic PT and whether the palpation meter (PALM), a tool to measure standing PT, is valid against 3-dimensional (3D) motion analysis. The purposes of this study were to (1)determine the criterion validity of the PALM for measuring standing PT and (2)identify the relationship between standing PT and dynamic PT during running. Participants (n = 25; 10 males and 15 females) had their standing PT measured by the PALM and 3D motion analysis. Dynamic PT variables were defined at initial contact and toe off. No relationship between the 2 tools was found. Significant large positive relationships between standing PT and PT at initial contact (r = .751, N = 25, P < .001) and PT at toe off (r = .761, N = 25, P < .001) were found. Since no relationship was found between standing PT measured by the PALM and 3D motion analysis, the PALM is not a valid alternative to 3D motion analysis. Clinicians may be able to measure standing PT and gain valuable information on dynamic PT, allowing clinicians to quickly assess whether further biomechanical testing is needed.

Balance and gait in progressive supranuclear palsy: a narrative review of objective metrics and exercise interventions.

The use of objective gait and balance metrics is rapidly expanding for evaluation of atypical parkinsonism, and these measures add to clinical observations. Evidence for rehabilitation interventions to improve objective measures of balance and gait in atypical parkinsonism is needed. Our aim is to review, with a narrative approach, current evidence on objective metrics for gait and balance and exercise interventions in progressive supranuclear palsy (PSP). Literature searches were conducted in four computerized databases from the earliest record up to April 2023: PubMed, ISI's Web of Knowledge, Cochrane's Library, and Embase. Data were extracted for study type (cross-sectional, longitudinal, and rehabilitation interventions), study design (e.g., experimental design and case series), sample characteristics, and gait and balance measurements. Eighteen gait and balance (16 cross-sectional and 4 longitudinal) and 14 rehabilitation intervention studies were included. Cross-sectional studies showed that people with PSP have impairments in gait initiation and steady-state gait using wearable sensors, and in static and dynamic balance assessed by posturography when compared to Parkinson's disease (PD) and healthy controls. Two longitudinal studies observed that wearable sensors can serve as objective measures of PSP progression, using relevant variables of change in turn velocity, stride length variability, toe off angle, cadence, and cycle duration. Rehabilitation studies investigated the effect of different interventions (e.g., balance training, body-weight supported treadmill gait, sensorimotor training, and cerebellar transcranial magnetic stimulation) on gait, clinical balance, and static and dynamic balance assessed by posturography measurements. No rehabilitation study in PSP used wearable sensors to evaluate gait and balance impairments. Although clinical balance was assessed in 6 rehabilitation studies, 3 of these studies used a quasi-experimental design, 2 used a case series, only 1 study used an experimental design, and sample sizes were relatively small. Wearable sensors to quantify balance and gait impairments are emerging as a means of documenting progression of PSP. Robust evidence for improving balance and gait in PSP was not found for rehabilitation studies. Future powered, prospective and robust clinical trials are needed to investigate the effects of rehabilitation interventions on objective gait and balance outcomes in people with PSP.

Taking Locomotion Mode as Prior: One Algorithm-Enabled Gait Events and Kinematics Prediction on Various Terrains

Both the discrete motion states and continuous joint kinematics are essential for controlling assistive robots under changeable environmental conditions. However, few studies investigate both the discrete and continuous motion intents. This paper is the first work to propose an end-to-end motion intent decoding method that integrates recognition of discrete locomotion modes and prediction of continuous joint kinematics and gait events. First, we propose a data-driven approach to segment the transitional periods of the adjacent locomotion modes and determine their boundaries. Second, we build a CNN-LSTM network that utilizes locomotion mode classification as the prior of joint kinematics and gait events prediction and thus decodes discrete and continuous motion intents. Finally, we evaluate our method through extensive experiments and comparisons. The proposed method for locomotion mode recognition achieves an accuracy of 98.73% for steady-state and 97.53% for transitional periods. For knee angle prediction, the method achieves the ahead-of-time prediction with NRMSE lower than 8.41%, R-value higher than 0.93, and R-square higher than 0.88 for various prediction time. For gait event prediction, it predicts the future timing of events with an error of 8.46 ms for initial contact, 32.76 ms for heel off, and 8.91 ms for toe off. This study reveals the feasibility of predicting locomotion-based kinematics and gait events on various terrains. The rich motion intents studied in this work highlight the potential of a more detailed lower-limb rehabilitation system.

Gait Event Detection with Proprioceptive Force Sensing in a Powered Knee-Ankle Prosthesis: Validation over Walking Speeds and Slopes.

Many powered prosthetic devices use load cells to detect ground interaction forces and gait events. These sensors introduce additional weight and cost in the device. Recent proprioceptive actuators enable an algebraic relationship between actuator torques and ground contact forces. This paper presents a proprioceptive force sensing paradigm which estimates ground reaction forces as a solution to detect gait events without a load cell. A floating body dynamic model is obtained with constraints at the center of pressure representing foot-ground interaction. Constraint forces are derived to estimate ground reaction forces and subsequently timing of gait events. A treadmill experiment is conducted with a powered knee-ankle prosthesis used by an able-bodied subject walking at various speeds and slopes. Results show accurate gait event timing, with pooled data showing heel strike detection lagging by only 6.7 ± 7.2 ms and toe off detection leading by 30.4 ± 11.0 ms compared to values obtained from the load cell. These results establish proof of concept for predicting gait events without a load cell in powered prostheses with proprioceptive actuators.

Splitting the Difference: Split-Belt Treadmill Training Improves Spatial and Temporal Gait Symmetry in People with Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative disease affecting two million people worldwide. This disease is characterized by degradation of the myelin sheath resulting in impaired neural communication throughout the body. As a result, most people with MS (PwMS) experience significant mobility impairments. Gait asymmetries between the two legs are prevalent leading to an increased risk of falls, musculoskeletal injury, and decreased quality of life. Recent work indicates that split-belt treadmill training, where the speed of each leg is controlled independently, can decrease gait asymmetries for other neurodegenerative impairments. In this study, 26 PwMS have undergone split-belt treadmill training, with the faster paced belt moving under the more affected limb. Phase coordination index (PCI), which measures temporal coordination to assess stepping accuracy and consistency, and limb excursion asymmetry (LEA), which measures spatial coordination by quantifying sagittal displacement from toe off to heel strike of the ipsilateral leg, are the primary outcome measures used to assess gait symmetry in the current study. Previous work has identified an average PCI for PwMS population to be 5.19%, thus we grouped participants based on their baseline PCI value as either 1) above (poor baseline symmetry) or 2) below (good baseline symmetry) the previously recorded MS mean PCI of 5.19%, predicting that participants with a baseline PCI greater than 5.19% would show a greater response to split-belt treadmill training. Preliminary results show a mean PCI change of -1.31% (SE=0.65) for the poor baseline symmetry group and a mean PCI change of 0.92% (SE: 0.32) (p=0.0062). Among participants with poor baseline symmetry, the mean LEA change is -13.02mm (SE: 5.25) compared to a mean LEA change of 0.83mm (SE=3.35) for participants with good baseline symmetry (p=0.037). These findings suggest that PwMS retain the ability for gait adaptation, and provide the template for a novel, targeted mobility intervention. Multiple sclerosis (MS) is a neurodegenerative disease affecting two million people worldwide. This disease is characterized by degradation of the myelin sheath resulting in impaired neural communication throughout the body. As a result, most people with MS (PwMS) experience significant mobility impairments. Gait asymmetries between the two legs are prevalent leading to an increased risk of falls, musculoskeletal injury, and decreased quality of life. Recent work indicates that split-belt treadmill training, where the speed of each leg is controlled independently, can decrease gait asymmetries for other neurodegenerative impairments. In this study, 26 PwMS have undergone split-belt treadmill training, with the faster paced belt moving under the more affected limb. Phase coordination index (PCI), which measures temporal coordination to assess stepping accuracy and consistency, and limb excursion asymmetry (LEA), which measures spatial coordination by quantifying sagittal displacement from toe off to heel strike of the ipsilateral leg, are the primary outcome measures used to assess gait symmetry in the current study. Previous work has identified an average PCI for PwMS population to be 5.19%, thus we grouped participants based on their baseline PCI value as either 1) above (poor baseline symmetry) or 2) below (good baseline symmetry) the previously recorded MS mean PCI of 5.19%, predicting that participants with a baseline PCI greater than 5.19% would show a greater response to split-belt treadmill training. Preliminary results show a mean PCI change of -1.31% (SE=0.65) for the poor baseline symmetry group and a mean PCI change of 0.92% (SE: 0.32) (p=0.0062). Among participants with poor baseline symmetry, the mean LEA change is -13.02mm (SE: 5.25) compared to a mean LEA change of 0.83mm (SE=3.35) for participants with good baseline symmetry (p=0.037). These findings suggest that PwMS retain the ability for gait adaptation, and provide the template for a novel, targeted mobility intervention.

Estimation of Gait Subphase Time Parameters Based on a Human Electrostatic Field Detection System

The parameters of gait phases obtained by detecting gait events can provide a robust basis for the pathological diagnosis and rehabilitation of patients with lower limb disorders. In this paper, a method is proposed to divide the inner-stance phase and inner-swing phase by detecting the gait events of heel-off (HO) and swing to the highest position (SHP) in the stepping electrostatic gait signal (EGS) and to estimate the subphase time parameters. The gait events are detected by using the local extreme points of the integrated signal of the EGS. Four subphase temporal parameters are obtained after combining the local extrema of the EGS representing the initial contact (IC) and toe-off (TO) for the division of the inner-stance and inner-swing phases. Compared with the motion capture system (VICON), the detection accuracy of the proposed method reaches 98.5%, and the measurement error is within the range of ±60 ms. Pearson’s coefficient ‘r’ was used to verify the correlation between the four gait subphases estimated by the two methods, and excellent agreement was obtained (r > 0.95, p < 0.05). Most of the measurement results of the four subphase temporal gait parameters are within the 95% confidence interval of the Bland–Altman analysis chart. The repeatability of the proposed method was calculated through intraclass correlation coefficients (ICC) and showed good test-retest reliability (ICC > 0.85, p < 0.01). This method detects gait events and estimates subphase duration with high accuracy and can provide a foundation for the gait analysis of EGSs.

Dynamic Changes in Lumbar Spine Kinematics During Gait May Explain Improvement in Back Pain and Disability in Patients With Hip-Spine Syndrome.

Prospective cohort. Determine if total hip arthroplasty (THA) changes lumbar spine kinematics during gait in a manner that explains the improvements in back pain seen in patients with hip-spine syndrome. For patients with hip-spine syndrome, improvements in both hip and back pain have been demonstrated after THA; however, the exact mechanism of improvement in back pain remains unknown, as no corresponding changes in lumbar spine static radiographic parameters have been identified. Thirteen patients with severe, unilateral hip osteoarthritis scheduled to undergo THA with concomitant back pain and disability were tested at baseline and 6 months after THA. Harris Hip Score (HHS) and Oswestry Disability Index questionnaires were completed; the static orientation of the spine and pelvis were measured on standing radiographs, and lumbar spine kinematics were measured during treadmill walking using a validated measurement system that matched subject-specific bone models created from CT scans to dynamic biplane radiographs. After THA, both the Oswestry Disability Index (36.3-11.3, P <0.001) and Harris Hip Score (55.7-77.9, P <0.001) improved; however, there were no changes in static intervertebral or pelvis orientation. During gait after THA, the overall lumbar spine (L1 to L5) was less lordotic from heel strike to contralateral toe off ( P <0.001), the L4 and L5 vertebra were less anteriorly tilted by 3.9° ( P =0.038) from midstance to contralateral heel strike and by 3.9° ( P =0.001) during stance, respectively. The decreased anterior tilt of the 2 lowest lumbar vertebrae and the corresponding loss of lumbar lordosis may reduce facet loading during the stance phase of gait after THA. This change in lumbar spine kinematics during gait is a potential mechanism to explain the observed improvements in back pain and disability after THA. 4.

Sagittal-plane balance perturbations during very slow walking: Strategies for recovering linear and angular momentum

Spatiotemporal gait characteristics change during very slow walking, a relevant speed considering individuals with movement disorders or using assistive devices. However, we lack insights in how very slow walking affects human balance control. Therefore, we aimed to identify how healthy individuals use balance strategies while walking very slow. Ten healthy participants walked on a treadmill at an average speed of 0.43ms−1, while being perturbed at toe off right by either perturbations of the whole-body linear momentum (WBLM) or angular momentum (WBAM). WBLM perturbations were given by a perturbation on the pelvis in forward or backward direction. The WBAM was perturbed by two simultaneous perturbations in opposite directions on the pelvis and upper body. The given perturbations had magnitudes of 4, 8, 12 and 16% of the participant’s body weight, and lasted for 150ms. After perturbations of the WBLM the centre of pressure placement was modulated using the ankle joint, while keeping the moment arm of the ground reaction force (GRF) with respect to the centre of mass (CoM) small. After the perturbations of the WBAM a quick recovery was initiated, using the hip joint and adjusting the horizontal GRF to create a moment arm with respect to the CoM. These findings suggest no fundamental differences in the use of balance strategies at very slow walking compared to normal speeds. Still as the gait phases last longer, this time was exploited to counteract perturbations in the ongoing gait phase.

Inter-Session Repeatability of Marker-Less Motion Capture of Treadmill Running Gait

Twenty-one experienced runners completed three treadmill running sessions on different days. Each session consisted of three consecutive 2 min trials at self-selected speeds (RPE = 3, 5, and 7). An eight-camera marker-less motion capture system and instrumented pressure treadmill (TM) collected data over the final ~25 s at each speed. Lower extremity joint angles (ankle, knee, and hip) and segmental angles (pelvis and trunk) were computed for each trial with foot contact and toe off being kinematically determined. Spatiotemporal metrics (ground contact time, step length, and cadence) were measured via TM and compared to their kinematically derived counterparts. All spatiotemporal metrics demonstrated excellent agreement (ICCs &gt; 0.98). Both intra-trial and inter-session variability, averaged across the entire running cycle, for all lower extremity joint angles in all planes were low (intra-trial: sagittal = 2.0°, frontal = 1.2°, and transverse = 1.9°; inter-session: sagittal = 1.4°, frontal = 0.8°, and transverse = 1.3°). Discrete measures of lower extremity joint and segmental angles were evaluated for inter-session reliability at foot contact, toe off, and peak value during the stance phase. On average, discrete measures demonstrated good reliability (ICCsagittal = 0.85, ICCfrontal = 0.83, and ICCtransverse = 0.77) with average standard error of measurement &lt; 1°. Marker-less motion capture reliably measured treadmill running kinematics in a group of runners demonstrating heterogenous foot strike patterns (13 rearfoot strike and 8 non-rearfoot strike) across a range of speeds (2.67–4.44 m/s).

Mechanical adaptations in walking using carbon fiber ankle foot orthoses for patients with peripheral artery disease

BackgroundThe effectiveness of community-based walking programs for patients with peripheral artery disease (PAD) can be limited by calf claudication during exercise. Recent evidence finds adding carbon fiber ankle foot orthoses (AFO) to a walking program can result in improvements in patient mobility and delay claudication onset when walking. Research questionHow may carbon fiber AFO alter ankle walking mechanics and corresponding triceps surae muscle recruitment in a manner that could improve patient mobility? MethodsIn this repeated measures cohort study, fifteen patients with PAD were fit with bilateral AFO before completing self-paced gait analysis including electromyography. Patients were then given standard advice to walk at home using the devices for 12 weeks. Twelve patients completed follow-up testing. ResultsThere were no significant interactions between main effects for any variable of interest (p ≥ 0.189). Further, there were no within-subjects main effects for testing time for self-selected gait speed or any of the kinetic or kinematic variables (p ≥ 0.435). There were significant main effects for AFO use with reductions in dorsi flexion (p < 0.001), plantar flexion at toe off (p < 0.001), ankle plantar flexor moment (p = 0.037), and ankle plantar flexor power (p < 0.001). Triceps surae recruitment did not change between AFO conditions (p > 0.05). SignificanceAdding carbon fiber AFO limits peak ankle motion and joint power during self-paced walking for people with PAD while maintaining their walking speed. These gait adaptions were maintained over our 12 weeks of walking practice time. A resulting decrease in plantar flexor power while maintaining gait speed may provide the mechanism by which AFO can delay claudication onset which are major barrier to PAD walking programs. Calf muscle recruitment was maintained when adding the AFO which suggests sufficient muscle exertion could exist to maintain muscle integrity with sustained AFO use.

Rehabilitation of Geriatric Burn Patient Post-Meek Micrograft with Bilateral Partial Calcanectomy: A Case Report

Looking along the physiological and physical changes in aging, in the light of a major burn, co-morbidities, surgical intervention and precaution, a geriatric burn patient requires a delicate balance of ideal burn care and rehabilitation to achieve functional independence. A 70-year-old patient, with 30% total body surface area flame burn injury, underwent bilateral partial calcanectomy secondary to calcaneus osteomyelitis, and Meek micrograft technique for burn injury on bilateral lower extremities, is presented in this case report. In order to ensure good graft take, her knees were immobilized causing bilateral soft tissue contractures. Subsequently, upon initiation of ambulation, gait abnormalities observed include absence of heel off and toe off, with heel walking. The patient was admitted for intensive inpatient rehabilitation, where significant improvement in the knee range of motion and ambulation were achieved. The patient was eventually discharged ambulatory with walker. Despite expected complications, rehabilitation management proved to be beneficial in improving function and ambulation in geriatric burn patient.

Heel‐Strike and Toe‐Off Detection Algorithm Based on Deep Neural Networks Using Shank‐Worn Inertial Sensors for Clinical Purpose

A foot placement of inertial sensors is commonly used for heel‐strike (HS) and toe‐off (TO) event detection. However, in clinical practice, such sensor placement may be difficult or even impossible due to the deformity of patients’ feet. The first contribution of this paper is a new algorithm for HS and TO event detection for cases when the sensors are placed on the lateral malleolus. Such sensor placement allows gait analysis in patients with foot deformities. In addition, the placement of the sensor directly on the wide bone surface of the lateral malleolus ensures secure fixation of the sensor during walking. The proposed algorithm is based on deep neural networks, which can be easily adapted (by retraining the neural networks) for analysis of various pathological gait patterns. It is especially important in clinical practice when the number of possible pathological gait patterns is very large. The algorithm proposed in this paper was implemented in a new wearable system for the clinical gait analysis. The second contribution is a validation of this new wearable system. The performance of both proposed algorithm and gait analysis system was evaluated against a reference treadmill system where a capacitance–based pressure platform was used. A total of 117 healthy volunteers participated in the comparison (62 males and 55 females, age 24–55 years, height 162–183 cm). They were asked to perform 2 min walking trials with different speed. Mean accuracy ± precision was –0.021 ± 0.091 s for gait cycle, 0.589 ± 1.144 steps/min for cadence, –0.051 ± 0.544% for stance phase, –0.37 ± 0.649% for single support, 0.296 ± 0.711% for double support, 0.132 ± 0.561% for load response, and 0.106 ± 0.661% for preswing. Limitations of the proposed algorithm and its compassion with state‐of‐the‐art algorithms were discussed.

Human gait-labeling uncertainty and a hybrid model for gait segmentation.

Evaluate manual labeling uncertainty and introduce a hybrid stride detection and gait-event estimation model for autonomous, long-term, and remote monitoring. Estimate inter-labeler inconsistencies by computing the limits-of-agreement. Develop a hybrid model based on dynamic time warping and convolutional neural network to identify valid strides and eliminate non-stride data in inertial (walking) data collected by a wearable device. Finally, detect gait events within a valid stride region. The limits of inter-labeler agreement for key gait events heel off, toe off, heel strike, and flat foot are 72, 16, 24, and 80 ms, respectively; The hybrid model's classification accuracy for stride and non-stride are 95.16 and 84.48%, respectively; The mean absolute error for detected heel off, toe off, heel strike, and flat foot are 24, 5, 9, and 13 ms, respectively, when compared to the average human labels. The results show the inherent labeling uncertainty and the limits of human gait labeling of motion capture data; The proposed hybrid-model's performance is comparable to that of human labelers, and it is a valid model to reliably detect strides and estimate the gait events in human gait data. This work establishes the foundation for fully automated human gait analysis systems with performances comparable to human-labelers.