Stance Phase Duration Research Articles

Gait training facilitates push-off and improves gait symmetry in children with cerebral palsy

BackgroundHuman walking involves a rapid and powerful contraction of ankle plantar flexors during push-off in late stance. ObjectiveHere we investigated whether impaired push-off force contributes to gait problems in children with cerebral palsy (CP) and whether it may be improved by intensive gait training. MethodsSixteen children with CP (6–15 years) and fourteen typically developing (TD) children (4–15 years) were recruited. Foot pressure was measured by insoles and gait kinematics were recorded by 3-dimensional video analysis during treadmill and overground walking. The peak derivative of ground reaction force at push off (dPF) was calculated from the foot pressure measurements. Maximal voluntary plantar flexion (MVC) was measured while seated. Measurements were performed before and after a control period and after 4 weeks of 30 minutes daily inclined treadmill training. ResultsdPF and MVC were significantly lower in children with CP on the most affected (MA) as compared to TD children (p < .001). dPF was lower on the MA leg as compared to the less affected (LA) leg in children with CP (p < .05). Following gait training, increases in dPF (p < .001) and MVC (p < .01) were observed for the MA leg. Following gait training children with CP showed similar timing of dPF and similar stance phase duration on both legs indicating improved symmetry of gait. These effects were also shown during overground walking. ConclusionImpaired ability to voluntarily activate ankle plantar flexors and produce a rapid and powerful push-off during late stance are of importance for impaired gait function in children with CP. Intensive treadmill training may facilitate the drive to ankle plantar flexors and reduce gait asymmetry during both treadmill and overground walking.

Effect of ankle-foot orthosis on level walking in healthy subjects.

An ankle-foot orthosis is often prescribed in the rehabilitation of patients with neurological motor disorders such as hemiparesis. However, walking with a unilateral ankle-foot orthosis may not be effectively achieved just by trying to reproduce normal intact walking with a symmetrical gait pattern. Understanding skills to facilitate walking gait with a unilateral ankle-foot orthosis has implications for better rehabilitative interventions to help restore walking ability in patients with stroke. We, therefore, analyzed the kinematics and ground reaction forces of walking with and without an ankle-foot orthosis in healthy subjects to infer the possible skills to facilitate walking gait with a unilateral ankle-foot orthosis. Adult male participants were asked to walk with and without an ankle-foot orthosis across two force platforms set in a wooden walkway, and body kinematics and ground reaction force profiles in the sagittal plane were simultaneously recorded. We found that the forward tilting angle of the trunk at the time of toe-off of the leg with the ankle-foot orthosis was significantly larger than that of the leg without the ankle-foot orthosis, to adaptively compensate for the loss of ankle joint mobility due to the unilateral ankle-foot orthosis. Furthermore, the peak vertical ground reaction force at heel-contact was significantly larger in the leg without the ankle-foot orthosis than in the leg with the ankle-foot orthosis owing to the fact that the stance phase duration of the leg with the ankle-foot orthosis was relatively shorter. Such information may potentially be applied to facilitate walking training in stroke patients wearing a unilateral ankle-foot orthosis.

Stride kinematic changes in laminitic horses treated with three different types of hoof orthopedic devices

Considering the hypothesis that laminitic horses display changes in the kinematics of their forelimbs and clog type orthopedic devices can be beneficial in such cases, the objectives of this study were to compare the stride pattern of healthy horses versus that of horses with chronic laminitis and to assess the kinematic effects of three types of clog shoes on the stride of laminitic horses. Six healthy and six laminitic mares were subjected to a kinematic evaluation at a walk. The horses with laminitis were evaluated before and after the use of three different models of clog type orthopedic shoes on the hooves of both their forelimbs. The treatment types that were administered were the application of no shoes, wooden shoes, leather and ethylene-vinyl acetate (EVA) shoes, and wooden and EVA shoes. The horses with laminitis have a stride length that is reduced by 11% (P = 0.03), and in the swing phase, by 18% (P = 0.004), and the relative stance phase of each limb is prolonged by 6% (P = 0.02) when compared with the healthy group. However, values associated with the stride duration, stance phase duration, breakover duration, speed, and frequency were not significantly different among the laminitic groups. Further, no statistical differences were found in the comparison of the outcomes among the treatments administered to the horses with laminitis, except in their stride length, which was longer in the horses shod with wooden clogs when compared with in the unshod laminitic horses (P = 0.04). It was concluded that horses with stable chronic laminitis display changes in the kinematics of their forelimbs while walking. Immediate and remarkable beneficial effects were not observed with the use of all the types of orthoses; however, the wooden clog resulted in a significant improvement in the length of the stride. Further studies are needed to verify the prolonged effects of clog shoe-type ortheses in the different phases of equine laminitis.

Reliability and minimum detectable change of measures of gait in children during walking and running on an instrumented treadmill

BackgroundInstrumented treadmills that incorporate pressure platforms are increasingly used to characterize gait in children. Although footprint size is known to influence the measurement performance of pressure platforms, published evidence on the reliability of such systems for children’s gait is lacking. Research questionThis study evaluated the test–retest reliability of temporospatial gait parameters and vertical ground reaction forces measured in healthy children during barefoot walking and running on a capacitance–based treadmill system. MethodsTemporospatial gait parameters, including cadence, stride length, stride duration, stance and swing phase durations and the magnitude and timing of conventional vertical ground reaction force peaks were determined on two occasions in 17 healthy children (mean age, 11 ± 2 years; height, 148.4 ± 9.3 cm; and mass, 43.3 ± 10 kg) during walking and running at preferred speed on an instrumented treadmill. Reliability was assessed using Intra Class Correlation Coefficients (ICC) and the standard error of measurement (SEM). The minimum detectable change (MDC95%) was also calculated. ResultsICC values ranged from 0.91–0.99 for all variables. When expressed as a percentage of the mean, the SEM was <5% for all gait parameters assessed during walking and running. The MDC95% values for gait parameters were typically higher during running than walking, and were ±4% of the gait cycle for temporal parameters, ±55 cm for stride length and ±0.1 bodyweights for peak vertical ground reaction force. SignificanceChildren’s gait parameters varied by <5% between test occasions and were more consistent during walking than running. These findings provide clinicians and researchers with an index of the reliability and sensitivity of the treadmill to detect changes in common spatiotemporal gait parameters and vertical ground reaction forces in children.

How do novice and improver walkers move in their home environments? An open-sourced infant's gait video analysis.

ObjectiveNatural independent walking mostly occurs during infant´s everyday explorations of their home environment. Gait characteristics of infant walkers at different developmental stages exist in literature, however, data has been only collected in laboratory environments, which may reduce gait variability, therefore mask differences between developmental stages of natural gait. The aim of the study was to provide the first data set of temporal and functional gait characteristics of novice and improver infant walkers in familiar environment conditions in their home. We hypothesised that familiar environment conditions may effectively demonstrate natural gait characteristics and real differences in gait variables differing between 2 groups of developing infant walkers.MethodsIn a cross-sectional design; we used open-source videos of infants in their home environments: twenty videos of 10 novice (5 girls, 5 boys, 7–12 months) and 10 improver (4 girls, 6 boys, 8–13 months) walkers were chosen from an open-source website. 2-D video gait analysis was undertaken for these parameters: falls frequency, frequency of stops, gait cadence, and time of stance phase, swing phase, and double support. Between groups comparison for novice versus improver was investigated by Mann-Whitney U tests (p ≤ 0.05) with determination of effect size of Pearson r correlation.ResultsStatistically significant differences between groups with large effect sizes were found for these parameters: falls frequency (p = 0.01, r = 0.56); cadence (p = 0.01, r = 0.57); stance phase duration of right leg (p < 0.01, r = 0.63); stance phase duration of left leg (p = 0.01, r = 0.56); and double support phase duration (p < 0.01, r = 0.69). Novices scored higher in comparison with improver walkers in all the parameters except cadence.ConclusionsThis study presents the first data set of functional and temporal gait parameters of novice and improver infant walkers in their home environments. As an addition to recent research, novice infants walk with lower cadence and higher falls frequency, stance phase time and double support in their familiar environments. With increasing experiences, infant´s cadence increases while the other parameters decrease.

Use of validated objective methods of locomotion characteristics and weight distribution for evaluating the efficacy of ketoprofen for alleviating pain in cows with limb pathologies.

In veterinary practice pain alleviation plays a part in managing lameness. The aim of this randomized and placebo-controlled clinical study was to evaluate the effect of a single administration of ketoprofen on locomotion characteristics and weight distribution in cattle with foot (located up to and including the fetlock; n = 31) and (proximal to the fetlock; n = 10) pathologies. Cattle were randomly allocated to either the ketoprofen (group K; intravenous 3 mg/kg of body weight; n = 21) or an equivalent volume of isotonic sterile saline solution (group P; n = 20). Two accelerometers (400 Hz; kinematic outcome = stance phase duration; kinetic outcome = foot load and toe-off), a 4-scale weighing platform (weight distribution and SD of the weight) and a subjective locomotion score were measured before (baseline) and after 1 h and 18 h of treatment. All variables were expressed as differences across contralateral limbs, and the measurements at 1 h and 18 h were compared to the baseline. A repeated measures ANOVA was used to determine the differences between groups K and P. A logistic regression model with a binary outcome (0 = no improvement and 1 = improvement of the differences across the contralateral limbs over time) was calculated. Mean (± SD) of locomotion scores at baseline were not significantly different (P = 0.102) in group K (3.10 ± 0.80) as compared to group P (3.48 ± 0.64). Cattle of group K showed significantly lower differences across contralateral limbs at 1 h as compared to group P for the relative stance phase and the weight distribution. Only the treatment (P versus K) remained a significant factor in the model for relative stance phase (odds ratio (OR) = 6.5; 95% CI = 1.38–30.68) and weight distribution (OR = 6.36; 95% CI = 1.30–31.07). The effects of ketoprofen were evident in improving the differences across contralateral limbs—both for stance phase during walking and weight bearing during standing—after 1 h but not after 18 h of administration.

Vertical ground reaction forces during gait in children with and without calcaneal apophysitis

BackgroundHeightened vertical load beneath the foot has been anecdotally implicated in the development of activity-related heel pain of the calcaneal apophysis in children but is supported by limited evidence. Research questionThis study investigated whether vertical loading patterns during walking and running differed in children with and without calcaneal apophysitis. MethodsVertical ground reaction force, peak plantar pressure (forefoot, midfoot, heel) and temporospatial gait parameters (cadence, step length, stride, stance and swing phase durations) were determined in children with (n = 14) and without (n = 14) calcaneal apophysitis. Measures were acquired during barefoot walking and running at matched and self-selected speed using an instrumented treadmill, sampling at 120 Hz. Statistical comparisons between groups were made using repeated measure ANOVAs. ResultsThere were no significant between group differences in vertical ground reaction force peaks or regional peak plantar pressures. However, when normalised to stature, cadence was significantly higher (≈ 5%) and step length shorter (≈ 5%) in children with calcaneal apophysitis than those without, but only during running (P <.05). Maximum pressure beneath the rearfoot during running was significantly correlated with self-reported pain in children with calcaneal apophysitis. SignificancePeak vertical force and plantar pressures did not differ significantly in children with and without calcaneal apophysitis during walking or running. However, children with calcaneal apophysitis adopted a higher cadence than children without heel pain during running. While the findings suggest that children with calcaneal apophysitis may alter their cadence to lower pressure beneath the heel and, hence pain, they also highlight the benefit of evaluating running rather than walking gait in children with calcaneal apophysitis.

Heuristic Real-Time Detection of Temporal Gait Events for Lower Limb Amputees

This paper presents a complete system and algorithm to estimate temporal gait events during stance and inner-stance phases using a single inertial measurement unit (IMU) in real-time. Validation of the proposed system was carried out by placing the foot-switches (FSW) directly underneath the foot. The performance of the system was assessed with eleven control subjects (CS), one unilateral transfemoral amputee (TFA), and one unilateral transtibial amputee (TTA), while performing level ground walk and ramp activities. The experimental results showed reasonable agreement in timing differences of all the gait events in both groups when compared against the reference system. However, high data latency was observed for TFA in the case of Foot-Flat Start (FFS) and Heel-Off (HO). The slight variation in the positioning of IMU on the shank and the foot-switches underneath the foot and the difference in the kinematics of CS and lower limb amputees are probable reasons for large variations in the time difference. Overall, the detection accuracy was found to be 100% for Initial Contact, FFS, and Toe-Off, and 98.3% for HO. In addition, a high correlation was observed between estimated stance phase duration (SPD) from IMU and the SPD from FSW data. The proposed system showed high accuracy in the detection of temporal gait events which could potentially be employed in the gait analysis applications and the finite-state control of lower limb prostheses/orthoses.

Tibial and calcaneal coupling during walking in those with chronic ankle instability

BackgroundIt is estimated that nearly 2 million individuals sprain their ankle each year in the US. A majority of these are recurrent injuries, which often results in chronic ankle instability. To better understand the cause of instability, previous research has looked at the coupling or coordination between leg and foot motion during locomotion. Research QuestionDetermine the coupling between the tibia and the calcaneus during the stance phase of walking in those without a history of ankle instability compared to those with either moderate or severe instability. MethodsFifty-four individuals between the age of 18-30 years (15 males; 39 females) participated in this study. Each participant’s history of ankle sprains and score on the Cumberland Ankle Instability survey was used to assign them to either a no, moderate or severe instability group. Electromagnetic sensors attached to the tibia and calcaneus recorded three-dimensional movement of their tibia and calcaneus during the stance phase of barefoot over ground walking. The kinematic data was referenced to the subject’s standing position and time normalized to each subject’s stance phase duration. The relative phase (RP) angle and RP variability between tibia internal/external rotation and calcaneal inversion/eversion motion was then calculated. A one-way analysis of variance test was used to determine if significant differences existed between the three groups of subjects on mean RP angle or variability. An alpha level of .05 was used to determine statistical significance. ResultsA significant increase in RP angle and variability was found during the mid-stance phase of walking for those with severe ankle joint instability compared to those with moderate or no instability. Significance. The observed decreased coordination and increased coupling variability observed for those with severe ankle instability suggests either residual ligamentous damage, inadequate sensorimotor control, or both.

Development of a Mechanistic Hypothesis Linking Compensatory Biomechanics and Stepping Asymmetry during Gait of Transfemoral Amputees.

Objective Gait asymmetry is a common adaptation observed in lower-extremity amputees, but the underlying mechanisms that explain this gait behavior remain unclear for amputees that use above-knee prostheses. Our objective was to develop a working hypothesis to explain chronic stepping asymmetry in otherwise healthy amputees that use above-knee prostheses. Methods Two amputees (both through-knee; one with microprocessor knee, one with hydraulic knee) and fourteen control subjects participated. 3D kinematics and kinetics were acquired at normal, fast, and slow walking speeds. Data were analyzed for the push-off and collision limbs during a double support phase. We examined gait parameters to identify the stepping asymmetry then examined the external work rate (centre of mass) and internal (joint) power profiles to formulate a working hypothesis to mechanistically explain the observed stepping asymmetry. Results Stepping asymmetry at all three gait speeds in amputees was characterized by increased stance phase duration of the intact limb versus relatively normal stance phase duration for the prosthesis limb. The prosthesis limb contributed very little to positive and negative work during the double support phase of gait. To compensate, the intact leg at heel strike first provided aid to the deficient prosthetic ankle/foot during its push-off by doing positive work with the intact knee, which caused a delayed stance phase pattern. The resulting delay in toe-off of the intact limb then facilitated the energy transfer from the more robust intact push-off limb to the weaker colliding prosthesis side. This strategy was observed for both amputees. Conclusions There is a sound scientific rationale for a mechanistic hypothesis that stepping asymmetry in amputee participants is a result of a motor adaptation that is both facilitating the lower-leg trajectory enforced by the prosthesis while compensating for the lack of work done by the prosthesis, the cost of which is increased energy expenditure of the intact knee and both hips.

Modeling the central nervous system functionality in controlling the calf muscle activity during running with sport shoes.

Biological findings show that the activity of the calf muscle group is controlled by the central nervous system during running. The central nervous system tries to retain the peak values of the ground reaction force at constant levels as well as to minimize the vibration amplitude of soft tissues of the lower leg. Furthermore, these objectives are functions of stiffness and damping (compliance properties) of the calf muscle-tendon unit, especially gastrocnemius-Achilles. In this article, a new model for the calf muscle-tendon unit activity is presented in which the coefficients of stiffness and damping are exponential functions of the force produced at the Achilles tendon in the duration of stance phase, that is, they are time variant instead of having constant values. Then, the central nervous system functionality to control the activity of the muscle-tendon unit is formulated through definition of an optimization problem. This problem is solved by additionally considering the hardness of sport shoes. The muscle activity is indeed controlled via optimally adjusting two tuning parameters of the muscle-tendon unit model in terms of the hardness of shoes. This idea is examined separately for two running speeds. The results show the following: (1) The hardness of shoes affects the muscle activity. We find safe areas of the hardness parameters to design sport shoes. (2) When hard shoes are worn, the running speed has negligible effects on the tuning parameters, while with soft shoes the tuning parameters significantly change the muscle activity and the ground reaction force depended on running speed. (3) The ability of muscle in changing its compliance properties (specified by bound limits over the muscle-tendon unit tuning parameters) has the most influence in the safe area. (4) Rising running speed leads to a decrease in the safe area of shoes' parameters.

Objective assessment of lameness in cattle after foot surgery.

Assessment of lameness in cattle after foot surgery is important to monitor the recovery period, to improve the long-term success and the cows` welfare. This longitudinal multicenter retrospective study was carried out to evaluate the usefulness of automated tools of weight bearing and gait analysis following foot surgery to support the clinician to monitor lameness in cattle. For this purpose, the effect of involvement of different anatomical structures and the use of different surgery methods on gait parameters of post-operative recovery was assessed. The study consisted of 2 experiments and included cattle with unilateral foot pathologies located in the digital region which needed 1 (experiment 1; n = 30) or 2 (experiment 2; n = 4) surgical interventions. The surgical techniques were debridement, joint lavage, partial resection of bones, tendons or synovial structures, total resection of the sesamoid bone and digit amputation. Two accelerometers (400 Hz; kinematic outcome = stance phase duration; kinetic outcome = foot load and toe-off), a 4-scale weighing platform (difference of mean weight distribution across the limbs; Δweight) and a subjective locomotion score were used to evaluate gait parameters every 3 to 4 days after surgery. A repeated measures ANOVA was used in experiment 1 and a receiver operator characteristic analysis was used to determine the optimal cutoff values in experiment 2. Results showed that the differences across limbs for the pedogram variables of stance phases and peaks of foot load and toe-off, Δweight and the locomotion score were highest if joints or sesamoid bones were involved, suggesting that these cattle were more severely lame compared to cattle with more superficial foot pathologies. There was a significantly lower degree of lameness after surgical debridement and after digit amputation compared to partial and total resection of anatomical structures of the foot. The use of accelerometers and a 4-scale weighing platform represent promising objective tools for post-operative monitoring of lameness and can support the clinician in gait assessment to improve the long-term success of surgical interventions in the area of the foot.

Comparison of ground reaction force measurements in a population of Domestic Shorthair and Maine Coon cats.

Current research on gait analysis mostly involves horses and dogs. Feline kinetics and kinematics are being investigated and receiving more clinical interest at present. Ground reaction forces measured on pressure-sensitive mattresses have been established in healthy Domestic Shorthair cats (DSH). Currently, no further information exists on either breed-specific measured gait reaction forces or comparisons among breeds. Because Maine Coon (MC) cats appear to be over-represented with orthopaedic diseases of the hind limb (hip dysplasia, patellar luxation), we evaluated ground reaction force GRF measurements in MC cats and compared them with those of DSH cats. Pre-evaluation radiological and clinical exams determined that the cats were not lame. The parameters evaluated were peak vertical force (PFz), vertical impulse (IFz), time to PFz (TPFz), step length (SL), paw contact area (PCA), stance phase duration (SPD) and symmetry index (SI) for the fore- and hind limbs. In both breeds, PFz and IFz were greater in forelimbs than in hind limbs. The PFz and IFz in Newtons were higher in the MC cats compared to the DSH cats, but not after normalisation for total force (%TF) and body mass (%BM). Furthermore, due to their body conformation, MC cats have a longer SL, larger PCA, and higher body weight than DSH cats. No other parameters differed significantly, except that the TPFz displayed an earlier value in the MC hind limbs. Measured symmetry indices were similar to those reported in dogs and did not differ between breeds. This is the first study to report GRF values and temporospatial parameters in a healthy MC cat population. However, our results could not confirm differences between normalized PFz and IFz and temporospatial parameters between the breeds. The authors therefore conclude that genetic or other causes may be involved in orthopaedic hind limb pathogenesis seen in MC cats more often than in other breeds.

Improvement of cerebellar ataxic gait by injecting Cbln1 into the cerebellum of cbln1-null mice

Patients and rodents with cerebellar damage display ataxic gaits characterized by impaired coordination of limb movements. Here, gait ataxia in mice with a null mutation of the gene for the cerebellin 1 precursor protein (cbln1-null mice) was investigated by kinematic analysis of hindlimb movements during locomotion. The Cbln1 protein is predominately produced and secreted from cerebellar granule cells. The cerebellum of cbln1-null mice is characterized by an 80% reduction in the number of parallel fiber-Purkinje cell synapses compared with wild-type mice. Our analyses identified prominent differences in the temporal parameters of locomotion between cbln1-null and wild-type mice. The cbln1-null mice displayed abnormal hindlimb movements that were characterized by excessive toe elevation during the swing phase, and by severe hyperflexion of the ankles and knees. When recombinant Cbln1 protein was injected into the cerebellum of cbln1-null mice, the step cycle and stance phase durations increased toward those of wild-type mice, and the angular excursions of the knee during a cycle period showed a much closer agreement with those of wild-type mice. These findings suggest that dysfunction of the parallel fiber-Purkinje cell synapses might underlie the impairment of hindlimb movements during locomotion in cbln1-null mice.

Inertial data-based gait metrics correspondence to Tinetti Test and Berg Balance Scale assessments

Abstract The analysis of selected gait metrics and their correspondence to human gait and balance abilities is presented in this paper. Accelerometric and gyroscopic data have been acquired from 42 older patients for the entire Berg Balance Scale examination along with expert assessments and additional gait segments of a ca. 1 min duration evaluated by means of the Tinetti Test. The inertial data is analyzed for gait and step detection and subjected to a detailed gait analysis using four metrics for both legs separately: pitch angle change, average duration of step swing and stance phase, and the average phase duration ratio. The analysis is performed offline. The results are compared to expert assessments using Spearman's rank correlation coefficient with p

Geometric optimization of a self-adaptive robotic leg

This paper demonstrates the self-adaptive capabilities of a two-degree-of-freedom Hoeckens-pantograph robotic leg (inspired by underactuated mechanical fingers) as well as its optimization, allowing it to overcome unexpected obstacles during its swing phase. A multi-objective optimization of the mechanism’s geometric parameters is performed using a genetic algorithm to highlight the trade-off between two conflicting objectives and select an appropriate compromise. The first of those objective functions measures the leg’s passive adaptation capability through a calculation of the input torque required to initiate the desired sliding motion along an obstacle. The second objective function evaluates the free-space trajectory followed by the leg endpoint using three criteria: linearity, stance ratio, and height-to-width ratio. In comparison with the initial geometry based on the Hoecken’s linkage, the selected final mechanism chosen from the Pareto front shows an important improvement of the adaptation capabilities, at the cost of a slight decrease in the stance phase duration. This paper expands on mechanical self-adaptive design philosophy, which has recently attracted a lot of attention in the field of grasping, to legged locomotion and paves the way for subsequent experimental validation of this approach.

Can running kinetics be modified using a barefoot training program?

IntroductionThere is limited information about barefoot transition programs and this study will help to increase knowledge about this growing trend. The purpose of this study was, therefore, to determine the effect of a twelve-week barefoot training program on kinematic variables in long-distance runners. Materials and methodsA total of 32 well-trained, habitually shod, long-distance runners, randomized in a control group and an experimental group who undertook a barefoot training program. At pre-test and post-test, all participants, wearing their usual sneakers, performed running tests at self-selected recovery and competitive running speeds on a treadmill. Both conditions were recorded with a 240Hz video rate system and analyzed using a 2-D video editing program using photogrammetric techniques. Contact time, flight time, step duration and cadence were measured using an analysis of variance (ANOVA) with repeated measures was performed. ResultsIn posttest, only the duration of landing phase at high speed showed significant difference, the experimental group achieved a shorter time than the control group after the barefoot training program (0.032±0.007s vs. 0.038±0.006s). In relation to within-group differences, the control group showed an increase of duration of stance phase at low speed (Δ=0.014s, p=0.024) and a reduction of flight time at high speed (Δ=−0.014s, p=0.034). Moreover, the experimental group achieved a reduction of duration of landing phase at high speed (Δ=−0.008s, p=0.004). ConclusionsA twelve-week program of barefoot running changes the duration of the landing phase at high speed, being shorter in long-distance runners. In contrast, the runners who did not undertake the training showed an increase of duration of stance phase at low speed.

Lymphedema treatment’s effect of gait parameters

The purpose of this paper is to analyze the effect of specialized lymphedema treatment on the overall picture of gait. Before and after the therapy we executed a pilot study to observe the gait parameters. The examined patients were in different phases of conditions (Stages II, III and IV). The measurement was performed on an instrumented treadmill with self-selected velocity. During the experimentation the simplified kinematical parameters were calculated using the Zebris processing program. Applying the data of the treadmill equipped with pressure-measuring sensors, the force awaking in the forefoot, the midfoot and the heel on both legs, furthermore, the butterfly parameters and a few kinetical parameters (e.g. step length, step width, duration of stance and double stance phase) could be calculated. Based on the results of this present study the seriousness of the lymphedema significantly influences the kinematical and kinetical gait parameters, and the effectiveness of lymphedema management is exceedingly traceable with a pilot study.

Changes in hoof kinetics and kinematics at walk in response to hoof trimming: pressure plate assessment.

Appropriate hoof preparation and symmetry are linked to the well-being of the horse. Previous studies have shown the efficacy of pressure plates (PPs) in delivering objective biomechanical analysis. We aimed to assess the effect of hoof trimming on hoof biomechanics using a PP. Nine clinically sound Arabian horses were walked across a PP while foot strike was recorded by a digital camera. Kinetic and kinematic parameters were recorded before and after trimming. Changes were considered significant when p < 0.05. Vertical force (p = 0.026) and contact pressure (p = 0.006) increased after trimming. Stance-phase duration (p = 0.006), swing-phase duration (p = 0.023), and gait-cycle duration (p = 0.007) decreased significantly post-trimming. The observed changes in kinetic and kinematic parameters were related to hoof trimming. The reported results underline the importance of farriery practice and its effect on hoof biomechanics, which should be considered by both farriers and veterinarians.

A Novel 3D Pedestrian Navigation Method for a Multiple Sensors-Based Foot-Mounted Inertial System.

In this paper, we present a novel method for 3D pedestrian navigation of foot-mounted inertial systems by integrating a MEMS-IMU, barometer, and permanent magnet. Zero-velocity update (ZUPT) is a well-known algorithm to eliminate the accumulated error of foot-mounted inertial systems. However, the ZUPT stance phase detector using acceleration and angular rate is threshold-based, which may cause incorrect stance phase estimation in the running gait pattern. A permanent magnet-based ZUPT detector is introduced to solve this problem. Peaks extracted from the magnetic field strength waveform are mid-stances of stance phases. A model of peak-peak information and stance phase duration is developed to have a quantitative calculation method of stance phase duration in different movement patterns. Height estimation using barometer is susceptible to the environment. A height difference information aided barometer (HDIB) algorithm integrating MEMS-IMU and barometer is raised to have a better height estimation. The first stage of HDIB is to distinguish level ground/upstairs/downstairs and the second stage is to calculate height using reference atmospheric pressure obtained from the first stage. At last, a ZUPT-based adaptive average window length algorithm (ZUPT-AAWL) is proposed to calculate the true total travelled distance to have a more accurate percentage error (TTDE). This proposed method is verified via multiple experiments. Numerical results show that TTDE ranges from 0.32% to 1.04% in both walking and running gait patterns, and the height estimation error is from 0 m to 2.35 m.