Double Support Phase Research Articles

Is there a trade-off between economy and task goal variability in transfemoral amputee gait?

BackgroundEnergy cost minimization has been widely accepted to regulate gait. Optimization principles have been frequently used to explain how individuals adapt their gait pattern. However, there have been rare attempts to account for the role of variability in this optimization process. Motor redundancy can enable individuals to perform tasks reliably while achieving energy optimization. However, we do not know how the non-goal-equivalent and goal-equivalent variability is regulated. In this study, we investigated how unilateral transfemoral amputees regulate step and stride variability based on the task to achieve energy economy.MethodsNine individuals with unilateral transfemoral amputation walked on a treadmill at speeds of 0.6, 0.8, 1.0, 1.2 and 1.4 m/s using their prescribed passive prostheses. We calculated the step-to-step and stride-to-stride variability and applied goal equivalent manifold (GEM) based control to decompose goal-equivalent and non-goal-equivalent manifold. To quantify the energy economy, the energy recovery rate (R) was calculated based on potential energy and kinetic energy. Comparisons were made between GEM variabilities and commonly used standard deviation measurements. A linear regression model was used to investigate the trade-off between R and GEM variabilities.ResultsOur analysis shows greater variability along the goal-equivalent manifold compared to the non-goal-equivalent manifold (p < 0.001). Moreover, our analysis shows lower energy recovery rate for amputee gait compared to nonamputee gait (at least 20% less at faster walking speed). We found a negative relationship between energy recovery rate and non-goal-equivalent variability. Compared to the standard deviation measurements, the variability decomposed using GEM reflected the preferred walking speed and the limitation of the passive prosthetic device.ConclusionIndividuals with amputation cleverly leverage task redundancy, regulating step and stride variability to the GEM. This result suggests that task redundancy enables unilateral amputees to benefit from motor variability in terms of energy economy. The differences observed between prosthetic step and intact step support the development of prosthetic limbs capable of enhancing positive work during the double support phase and of powered prosthesis controllers that allow for variability along the task space while minimizing variability that interferes with the task goal. This study provides a different perspective on amputee gait analysis and challenges the field to think differently about the role of variability.

Inter-joint coordination during gait in people with multiple sclerosis: A focus on the effect of disability

BackgroundWalking difficulties, which are widespread among people with MS (pwMS), represent one of the major factors contributing to physical disability and, as such, may greatly affect an individual's independence and quality of life. In this context, the study of lower limb kinematics may provide an important contribution to unveiling the underlying mechanisms of walking dysfunctions in MS. However, limited information about the inter-joint coordination during gait—the functional relationship between joint pairs during the whole gait cycle—is available. MethodsWe retrospectively analyzed the gait patterns of 104 pwMS (56 women, 48 men, mean age 46.3, average Expanded Disability Status Scale score 3.5) and 84 unaffected individuals age-and-sex-matched, who underwent 3D computerized gait analysis carried out using an optical motion capture system. PwMS were also stratified into two groups according to their level of disability. Those with EDSS ≤ 3.5 (n = 62) formed the “low-mild disability” group, while those with EDSS > 3.5 (n = 42) were assigned to the “moderate-severe disability” group. The raw data were processed to calculate the main spatio-temporal parameters and the kinematics in the sagittal plane at the hip, knee, and ankle joints. At each point of the gait cycle, the angular values were employed to build angle-angle diagrams (cyclograms) for the hip-knee and the knee-ankle joint couples. Inter-joint coordination was quantified using geometric features of the cyclograms (i.e., area, perimeter, and dimensionless ratio) and compared between groups. For pwMS only, we also explored possible relationships between cyclograms parameters, disability level, and spatio-temporal parameters of gait. ResultsPwMS exhibit a well-known gait pattern characterized by reduced speed, stride length, increased step width, and double support phase duration. Their inter-joint coordination was found altered at both hip-knee and knee-ankle joint couples, as indicated by the significantly reduced cyclogram area and perimeter with respect to unaffected individuals. However, the detailed analysis of the angle-angle diagram trajectories showed some differences associated with the level of disability. In particular, pwMS with mild-low disability exhibit cyclograms partly superposed with those of unaffected individuals in the first half of the stance phase (hip-knee couple) and the second half of the swing phase (knee-ankle couple), while in those with a moderate-severe disability, the differences are substantially extended to the whole gait cycle. Significant moderate to large correlations were also observed between cyclogram area and perimeter, EDSS score, and spatio-temporal parameters of gait. ConclusionThe study of inter-joint coordination during gait in pwMS represents a useful source of information about the way lower limb joints interact, thus potentially expanding the knowledge of the mechanisms underlying walking dysfunctions associated with the disease. From a clinical perspective, the availability of reference data for the co-variation of hip-knee and knee-ankle joint angles during gait can effectively support both the characterization of the progression of the disease and the assessment of the effectiveness of rehabilitative treatments.

Relationship Between the Choice of Clinical Treatment, Gait Functionality and Kinetics in Patients With Comparable Knee Osteoarthritis.

Objective: The objective of this study was to investigate the relationship between the choice of clinical treatment, gait functionality, and kinetics in patients with comparable knee osteoarthritis. Design: This was an observational case-control study. Setting: The study was conducted in a university biomechanics laboratory. Participants: Knee osteoarthritis patients were stratified into the following groups: clinical treatment (conservative/total knee replacement (TKR) planned), sex (male/female), age (60–67/68–75), and body mass index (BMI) (<30/≥30). All patients had a Kellgren–Lawrence score of 2 or 3 (N = 87). Main Outcome Measures: All patients underwent gait analysis, and two groups of dependent variables were extracted:• Spatiotemporal gait variables: gait velocity, stride time, and double-support time, which are associated with patient functionality.• Kinetic gait variables: vertical, anterior–posterior, and mediolateral ground reaction forces, vertical free moment, joint forces, and moments at the ankle, knee, and hip. Multifactorial and multivariate analyses of variance were performed. Results: Functionality relates to treatment decisions, with patients in the conservative group walking 25% faster and spending 24% less time in the double-support phase. However, these differences vary with age and are reduced in older subjects. Patients who planned to undergo TKR did not present higher knee forces, and different joint moments between clinical treatments depended on the age and BMI of the subjects. Conclusions: Knee osteoarthritis is a multifactorial disease, with age and BMI being confounding factors. The differences in gait between the two groups were mitigated by confounding factors and risk factors, such as being a woman, elderly, and obese, reducing the variability of the gait compression loads. These factors should always be considered in gait studies of patients with knee osteoarthritis to control for confounding effects.

Editorial: Towards Real-World Deployment of Legged Robots

part of its weight up while walking. This novel design provides the advantage of being extremely safe and 18 low-cost. The design of the robot incorporates tendon wires to actuate the articulations attached to their 19 thin linkages. The robot employs a data-driven neural network approach for performing walking behaviors.Employing such approach enables to handle the underactuated nature of the robot since BALLU2 has only 21 2 actuated degrees of freedom per leg. In order to determine the transition function for walking, the authors 22 perform a correlation study to chose significant state variables. Then, they train a neural network to learn 23 transition times on both single and double support phases. Walking is accomplished in the real system at a 24 speed of 0.18m/s using an RGBD camera for onboard state estimation.

The Evaluation of Gait and Balance for Patients with Early Diabetic Peripheral Neuropathy: A Cross-Sectional Study.

ObjectiveFalls often occur in patients with diabetic neuropathy due to biomechanical alternation. The implication of diabetic peripheral neuropathy (DPN) on gait and balance remains poorly understood.MethodsA total of 11 dynamic gait, balance and electrophysiological parameters were evaluated in 176 participants. The biomechanical parameters were compared between groups.ResultsStride length and stride velocity were significantly lower in all subgroups of DPN compared with healthy subjects (p<0.05). Stance phase and double support phase were significantly higher, but swing phase were significantly lower across all subgroups of DPN than healthy subjects (p<0.05). Under eyes-open standing, the ML and AP range parameters of CoM sway, ankle sway and hip sway, CoM sway index, ankle swing index in both subclinical and confirmed DPN patients were all significantly higher compared to healthy subjects (p<0.05). Under eyes-closed standing, AP range parameters of CoM sway in subclinical DPN and confirmed DPN patients were significantly higher than healthy subjects (p<0.05). The hip sway areas in diabetics were significantly higher compared to healthy subjects (p<0.05).ConclusionThe abnormal biomechanical parameters existed in the early stages of patients with DPN. The static balance under eyes-open and eye-closed condition is maintained by ankle joint compensation strategy and hip joint protection strategy. An early evaluation and better risk management is essential for diabetic patients with a history of more than 5 years even without DPN clinical symptoms and signs.Clinical Trial Registration NumberNo. ChiCTR1800019179, www.chictr.org.cn.

Core Sets of Kinematic Variables to Consider for Evaluation of Gait Post-stroke.

BackgroundInstrumented gait analysis post-stroke is becoming increasingly more common in research and clinics. Although overall standardized procedures are proposed, an almost infinite number of potential variables for kinematic analysis is generated and there remains a lack of consensus regarding which are the most important for sufficient evaluation. The current aim was to identify a discriminative core set of kinematic variables for gait post-stroke.MethodsWe applied a three-step process of statistical analysis on commonly used kinematic gait variables comprising the whole body, derived from 3D motion data on 31 persons post-stroke and 41 non-disabled controls. The process of identifying relevant core sets involved: (1) exclusion of variables for which there were no significant group differences; (2) systematic investigation of one, or combinations of either two, three, or four significant variables whereby each core set was evaluated using a leave-one-out cross-validation combined with logistic regression to estimate a misclassification rate (MR).ResultsThe best MR for one single variable was shown for the Duration of single-support (MR 0.10) or Duration of 2nd double-support (MR 0.11) phase, corresponding to an 89–90% probability of correctly classifying a person as post-stroke/control. Adding Pelvis sagittal ROM to either of the variables Self-selected gait speed or Stride length, alternatively adding Ankle sagittal ROM to the Duration of single-stance phase, increased the probability of correctly classifying individuals to 93–94% (MR 0.06). Combining three variables decreased the MR further to 0.04, suggesting a probability of 96% for correct classification. These core sets contained: (1) a spatial (Stride/Step length) or a temporal variable (Self-selected gait speed/Stance time/Swing time or Duration of 2nd double-support), (2) Pelvis sagittal ROM or Ankle plantarflexion during push-off, and (3) Arm Posture Score or Cadence or a knee/shoulder joint angle variable. Adding a fourth variable did not further improve the MR.ConclusionA core set combining a few crucial kinematic variables may sufficiently evaluate post-stroke gait and should receive more attention in rehabilitation. Our results may contribute toward a consensus on gait evaluation post-stroke, which could substantially facilitate future diagnosis and monitoring of rehabilitation progress.

Analysis of Clinical Efficacy of Clearing Heat and Dispelling Paralysis Soup in the Treatment of Osteoarthritis of the Knee Joint and Its Effect on Patients' Motor Function.

Objective To investigate the effects of clearing heat and dispelling paralysis soup for osteoarthritis of the knee joint on the motor function of the knee joint and the level of inflammation of the organism in patients. Methods One hundred and sixteen patients with knee osteoarthritis admitted from January 2020 to May 2021 were selected and randomly divided into 2 groups, 58 cases in the control group were treated with loxoprofen sodium dispersible tablets, and 58 cases in the experimental group were treated with Qinghe dispel paralysis soup on the basis of the control group and the patients' balance ability analysis, gait parameter change analysis, VAS, JOA, AIMS2-SF scale assessment, and serum index. The treatment effects of the two treatment regimens were analyzed by testing. Results The anterior-posterior axis, left-right axis, A2-A6, A4-A8, and circumferential axis of the experimental group were lower than those of the control group after treatment (P < 0.05); the step length of the experimental group was higher than that of the control group after treatment (P < 0.05), and there were no significant differences in step speed, double-support phase, and step width (P > 0.05), but both groups improved significantly compared with those before treatment (P < 0.05); the VAS score of the experimental group was lower than that of the control group after treatment. The VAS scores of the experimental group were lower than those of the control group, and the scores of JOA and AIMS2-SF were higher than those of the control group (P < 0.05); the levels of TIMP-1 in the experimental group were higher than those in the control group, and the levels of TNF-α, TLR4, MMP-3, and IL-1 were lower than those in the control group after treatment (P < 0.05); there was no significant difference in the incidence of adverse reactions between the two groups during treatment (P > 0.05), and the efficiency of the experimental group was higher than that of the control group (P < 0.05). Conclusion Combined treatment with Qinghe dispel paralysis soup can better promote the recovery of balance, improve motor ability, and reduce the development of inflammation in the organism, with high safety and effectiveness.

An Adaptive Nonsingular Fast Terminal Sliding Mode Controller for Dynamic Walking of a 5-Link Planar Biped Robot in Both Single and Double Support Phases

This paper aims to design an improved adaptive nonsingular fast terminal sliding mode controller for a fully actuated planar biped robot with five degrees of freedom in the single support (SSP) and double support (DSP) phases in the presence of external perturbation and uncertainties. A new sliding surface was proposed to avoid singularities and the chattering phenomenon. The proposed controller guarantees fast convergence of error signals in finite time. Unlike similar studies, the presented method considers a whole cycle of one step of walking, including SSP, double impact, and DSP phases. Also, the proposed approach does not require a predefined upper limit to estimate uncertainty using an adaptive law. Notably, dynamic walking was preferred over static walking to achieve more similarity to human walking. The designed trajectories were determined according to the position of the waist and swinging legs ankle, which could then be converted into the position of joints using inverse kinematics equations. The simulation results were used to approve the proposed controller's fast and robust tracking performance in the presence of external disturbances, mass, and inertia uncertainties without predefined knowledge of their upper bounds.

The Role of Walking Experience in the Emergence of Gait Harmony in Typically Developing Toddlers.

The ability to walk without support usually develops in the first year of a typically developing toddler’s life and matures further in the following years. Mature walking is characterized by the correct timing of the different gait phases that make up a full gait cycle formed by stance, swing, and double support phases. The harmony of mature walking is given by a specific self-similar structure of the ratios between the durations of these phases (stride/stance, stance/swing, swing/double support), that in adults all converge to the golden ratio (phi, about 1.618). The aim of this longitudinal, prospective, experimental study was to investigate the evolution of this gait harmonic structure in the transition from supported to independent walking. In total, 27 children were recruited and recorded at various stages of locomotor development, ranging from neonatal stepping up to an independent walking experience of about six months. Differently from walking speed that progressively increased with age, the gait phase ratios started to converge to golden value only after the first independent steps, suggesting a relation to the maturation of the walking experience. The independent walking experience seems to represent a trigger for the evolution of a locomotor harmonic pattern in toddlers learning to walk.

Muscle activation profile is modulated by unexpected balance loss in walking

BackgroundDuring an unexpected loss of balance, avoiding a fall requires people to readjust their footing rapidly and effectively. A deeper understanding of muscle activation patterns in response to unexpected balance loss will provide insights into the mechanisms of balance recovery responses. This could have implications for treatment of people with balance deficits. Research questionExplore the differences in balance recovery responses to perturbations in different phases of the gait cycle (single-support vs. double-support) in terms of biomechanical behavior (i.e., stepping and dynamic stability characteristics) and lower-limb muscle activation patterns. MethodsMuscle activation patterns of the ankle and knee muscles and muscle fiber type recruitment resulting from unannounced, mediolateral (i.e., right/left) horizontal-surface perturbations during walking was investigated in twenty healthy adults (27.00 ± 2.79 years, ten females). Surface electromyography (sEMG) total spectral power for specific frequency bands (40–60 Hz, 60–150 Hz, 150–250 Hz, 250–400 Hz and 400–1000 Hz), from tibialis anterior (TA) and vastus lateralis (VL) muscles were analyzed. Three mixed-effects models assessed behavioral and lower-limb muscle activation patterns resulting from perturbations in the gait cycle's single- and double-support phases. Statistical significance was set a priori at p < 0.05. ResultsCompared to non-perturbed walking, we found a significant increase in the total spectral power of lower-extremity muscles during the first three seconds after perturbation. During the double-support phase of gait, we found a different muscle fiber type recruitment pattern between VL and TA muscles. However, there were no significant differences between VL and TA muscles for perturbations implemented in single-support phases. SignificanceOur findings support the notion that muscle operating frequency is modulated in real-time to fit functional goal requirements, such as a rapid change of footing in response to unexpected loss of balance in single and double-support phases of gait.

Kinematic Relations during Double Support Phase in Parkinsonian Gait

The gait of Parkinson’s disease (PD) patients is shuffling, slow, and hesitant. We investigated peculiar gait relations during the double support phase (DSP) in PD patients and healthy controls. We used 3D motion capture (SIMI) to collect kinematic parameters of the natural gait of 11 PD patients (Hoehn and Yahr 2–3, 5 females, 6 males) tested on medication and the same-sized control sample (5 females, 6 males). The difference between groups was evaluated by the Mann-Whitney U test; for target parameters, the Spearman correlation was computed. Compared to the controls, the Parkinsonian step length index was significantly smaller (0.27 vs. 0.35, p &lt; 0.05), step width index higher (0.12 vs. 0.09, p &lt; 0.05), and the DSP duration was extended (0.165 s vs. 0.13 s, p &lt; 0.05), whereas the single support phase was shortened (0.38 s vs. 0.4 s, p &lt; 0.05). The Parkinsonians were faster during DSP initiation and slower during DSP termination (0.908 m·s−1 vs. 0.785 m·s−1, p &lt; 0.05); the Parkinsonian speed was more constant. The patients showed significantly decreased range of motion (ROM) in the hip, ankle, and shoulder and adopted straighter posture during the gait. Understanding gait concatenations can update physiotherapy approaches to target the roots of movement problems instead of the consequences.

Do different multi-segment foot models detect the same changes in kinematics when wearing foot orthoses?

BackgroundDifferent multi-segment foot models have been used to explore the effect of foot orthoses. Previous studies have compared the kinematic output of different multi-segment foot models, however, no study has explored if different multi-segment foot models detect similar kinematic changes when wearing a foot orthoses. The aim of this study was to compare the ability of two different multi-segment foot models to detect kinematic changes at the hindfoot and forefoot during the single and double support phases of gait when wearing a foot orthosis.MethodsFoot kinematics were collected during walking from a sample of 32 individuals with and without a foot orthosis with a medial heel bar using an eight-camera motion capture system. The Oxford Foot Model (OFM) and a multi-segment foot model using the Calibrated Anatomical System Technique (CAST) were applied simultaneously. Vector field statistical analysis was used to explore the kinematic effects of a medial heel bar using the two models, and the ability of the models to detect any changes in kinematics was compared.ResultsFor the hindfoot, both models showed very good agreement of the effect of the foot orthosis across all three anatomical planes during the single and double support phases. However, for the forefoot, the level of agreement between the models varied with both models showing good agreement of the effect in the coronal plane but poorer agreement in the transverse and sagittal planes.ConclusionsThis study showed that while consistency exists across both models for the hindfoot and forefoot in the coronal plane, the forefoot in the transverse and sagittal planes showed inconsistent responses to the foot orthoses. This should be considered when interpreting the efficacy of different interventions which aim to change foot biomechanics.

Peculiarities of the biomechanical and innervative structure of walking of healthy children of the early age

Restoration of the locomotor function is one of the most essential problems of medicine. This problem becomes especially essential, when we deal with those children, who can’t walk from their birth. Term “abilitation” is used just in relation to such children, what means not retraining children the right stereotype of walking, but appearance of this skill and its further adequate development. Nowadays, more and more specialists, who occupy themselves with abilitation of children of the early age, realize necessity of the instrumental estimation of the locomotor function. This phenomenon is connected with the fact, that in contrast with the score system of estimation, instrumental estimation of walking is maximally concrete and exact, and complex investigation of the biomechanical and innervative structure of walking gives complete idea of the locomotor disturbances of the child. Authors of this article investigated biomechanical and innervative structure of walking of 4 healthy children at the age of 2–2.5 years. On the basis of these investigations, it has been revealed, that the following peculiarities of walking are characteristic of children at the age of 2: remarkable diminution of the mean walking velocity, increase of cadence and shortening of the step length, essential transformation of the temporal structure of walking (growth of duration of the stance and double-support phase and decrease of duration of the swing phase), flexion position of the lower extremities, displacement of all extreme values of the angular displacements to the right along the temporal axis, considerable prolongation of the maximums of activity, absence of the second maximum of activity in a number of muscles, severe disturbances in the resonance properties of the lower extremities. All these peculiarities point out to the immaturity of the process of locomotion in children at the age of 2. The received data are necessary first of all as the standard ones, because walking parameters of children with the locomotor disorders of the early age must be compared with the corresponding parameters of the healthy children of the same age.

Planar Five-link Biped Robot Movement over a Stepped Surface

Modeling the anthropomorphic robot movement is of great interest to researchers all over the world. At the same time, the movement control of a walking mechanism is always a high dimension challenge. The difficulty with the anthropomorphic robot control is also caused by the fact that such a mechanism has always a hybrid dynamics and represents a sequential change of two phases – the single support phase and the double support phase (phase of changing robot’s leg). At the single support phase and at another phase the behavior of the biped robot is described by a system of ordinary differential equations and by a system of linear algebraic equations, respectively.The task of biped robot movement control has been studied in detail for the case when the robot moves over the horizontal surface. Obstacles make the task significantly complicated. The paper considers the movement control of the biped robot over the surface that is a periodic alternation of horizontal sections and obstacles. The obstacles represent steps of the same height known. It is assumed that the lengths of horizontal sections and steps are known as well. The objective is to create a control that provides robot’s periodic movement over the specified surface according to inherent characteristics of a walking human.For the single support phase, the outputs are proposed, the equality of which to zero corresponds to the robot’s movement with a given set of characteristics. The paper presents the feedback controls that stabilize the proposed outputs for a finite amount of time. By choosing the feedback parameters, it is possible to adjust the stabilization time so that the outputs become equal to zero when reached the end of each step.It is shown that for the chosen control law, the problem of constructing the control of robot’s periodic movement is reduced to the solution of a nonlinear equation. In the paper, we discuss the approaches to solving this equation and present the results of numerical simulation.The results obtained can be used to solve the problem of providing control of the biped robot movement over the surfaces with obstacles of a more complicated shape.Modeling the anthropomorphic robot movement is of great interest to researchers all over the world. At the same time, the movement control of a walking mechanism is always a high dimension challenge. The difficulty with the anthropomorphic robot control is also caused by the fact that such a mechanism has always a hybrid dynamics and represents a sequential change of two phases – the single support phase and the double support phase (phase of changing robot’s leg). At the single support phase and at another phase the behavior of the biped robot is described by a system of ordinary differential equations and by a system of linear algebraic equations, respectively.The task of biped robot movement control has been studied in detail for the case when the robot moves over the horizontal surface. Obstacles make the task significantly complicated. The paper considers the movement control of the biped robot over the surface that is a periodic alternation of horizontal sections and obstacles. The obstacles represent steps of the same height known. It is assumed that the lengths of horizontal sections and steps are known as well. The objective is to create a control that provides robot’s periodic movement over the specified surface according to inherent characteristics of a walking human.For the single support phase, the outputs are proposed, the equality of which to zero corresponds to the robot’s movement with a given set of characteristics. The paper presents the feedback controls that stabilize the proposed outputs for a finite amount of time. By choosing the feedback parameters, it is possible to adjust the stabilization time so that the outputs become equal to zero when reached the end of each step.It is shown that for the chosen control law, the problem of constructing the control of robot’s periodic movement is reduced to the solution of a nonlinear equation. In the paper, we discuss the approaches to solving this equation and present the results of numerical simulation.The results obtained can be used to solve the problem of providing control of the biped robot movement over the surfaces with obstacles of a more complicated shape.

Differences in walking-to-turning characteristics between older adult fallers and nonfallers: a prospective and observational study using wearable inertial sensors.

Wearable inertial sensors have gradually been used as an objective technology for biomechanical assessments of both healthy and pathological movement patterns. This paper used foot-worn sensors for characterizing the spatiotemporal characteristics of walking and turning between older fallers and nonfallers. Thirty community-dwelling older fallers and 30 older nonfallers performed 10-m straight walking, turned 180° around a cone, and then walked 10-m back to the starting point. Specific algorithms were used to measure spatiotemporal gait (double support phase of the gait cycle, swing width, and minimal toe clearance) and turning parameters (turn duration and turn steps) using two foot-worn Physiolog inertial sensor system. The researchers directly exported data as reported by the system. Our findings indicated that older fallers showed 26.58% longer time (P = 0.036) and 13.21% more steps (P = 0.038) compared to nonfallers during turning. However, both groups decreased their walking velocity (both P < 0.001), increased double support (both P = 0.001), and increased the swing width (both P = 0.001) during the transition from walking to turning. The older nonfallers additionally increased toe clearance (P = 0.001). Compared with the fallers, the older nonfallers showed a larger change in the swing width (P = 0.025) and toe clearance (P = 0.025) in walking to turning. Older fallers may adopt a cautionary strategy while turning to reduce the risk of falls. Wearable sensors can provide the temporospatial characteristics of turning and reveal significant differences by fall status, indicating the potential of turning measures as possible markers for identifying those at fall risk.

A new human-like walking for the humanoid robot Romeo

This paper seeks to define the anthropomorphic walking motion for the humanoid robot Romeo. The main characteristics of the lower and upper limb motions of the human being during walking are adapted to Romeo taking into account its kinematics and its motor power. The proposed walking includes starting, periodic and stopping motions. A boundary value problem is stated and solved to define each of these three movements, which are composed of single and double support phases. The trajectory of the zero moment point (ZMP) is explicitly defined as a function of time. Thanks to the Essential model, the two horizontal coordinates of the center of mass (CoM) are adapted to the desired ZMP trajectory and joint movements of Romeo. Numerical results show the efficiency of our strategy to design human-like walking for Romeo.

Theoretical Rationale for Design of Tasks in a Virtual Reality-Based Exergame for Rehabilitation Purposes.

Virtual reality games are playing a greater role in rehabilitation settings. Previously, commercial games have dominated, but increasingly, bespoke games for specific rehabilitation contexts are emerging. Choice and design of tasks for VR-games are still not always clear, however; some games are designed to motivate and engage players, not necessarily with the facilitation of specific movements as a goal. Other games are designed specifically for the facilitation of specific movements. A theoretical background for the choice of tasks seems warranted. As an example, we use a game that was designed in our lab: VR Walk. Here, the player walks on a treadmill while wearing a head-mounted display showing a custom-made virtual environment. Tasks include walking on a glass bridge across a drop, obstacle avoidance, narrowing path, walking in virtual footsteps, memory, and selection tasks, and throwing and catching objects. Each task is designed according to research and theory from movement science, exercise science, and cognitive science. In this article, we discuss how for example walking across a glass bridge gives perceptual challenges that may be suitable for certain medical conditions, such as hearing loss, when perceptual abilities are strained to compensate for the hearing loss. In another example, walking in virtual footsteps may be seen as a motor and biomechanical constraint, where the double support phase and base of support can be manipulated, making the task beneficial for falls prevention. In a third example, memory and selection tasks may challenge individuals that have cognitive impairments. We posit that these theoretical considerations may be helpful for the choice of tasks and for the design of virtual reality games.

Seamless Temporal Gait Evaluation during Walking and Running Using Two IMU Sensors.

In this study, we proposed a framework for extracting gait events and extensive temporal features, seamlessly, during walking and running on a treadmill by constructing a finite state machine (FSM) transition rules based on two IMU sensors attached to the back of the shoes. Detailed innerclass states were defined to recognize the double support phase on walking gait and the double flight phase on running gait. Further, an in-depth speed-based analysis of temporal gait features can be performed for each tested speed with an automatic speed change detection algorithm based on the moving average filter applied to motion intensity data. The results have demonstrated that the FSM can accurately distinguish walking gait and running gait while also extract a detailed gait phase, respectively. This finding may contribute to a more flexible gait analysis where a change in speed or transition from walk to run can be anticipated and recognized accordingly.

Effects of Dual-Task Training on Gait Parameters in Elderly Patients with Mild Dementia.

This study aimed to investigate the effectiveness of dual-task training (DTT) compared to single-task training (STT), on gait parameters in elderly patients with mild dementia (MD). Twenty-four elderly patients with MD were randomly assigned to the DTT (n = 13) or the STT group (n = 11). The DTT group performed a specific cognitive-motor DTT, while the STT group received only motor task training. Both training sessions lasted 8 weeks, with a frequency of 3 days per week, and the cognitive functions and gait parameters were measured. A statistically significant interaction effect was found between the two groups in stride length, stride velocity, cadence, step length, swing phase, stance phase, and double support phase (p < 0.05). After 8 weeks, the DTT group showed significant improvement in spatiotemporal parameters, except for the kinematic parameters (p < 0.05). In the between-group analysis, the DTT group showed more improvement than the STT group in stride velocity, step length, swing phase, stance phase, and double support (p < 0.05). These findings suggest that improvements in spatiotemporal gait parameters after DTT are reported in patients with MD. Our results can guide therapists to include dual tasks in their gait rehabilitation programs for the treatment of mild dementia.

Acute effects of acupuncture in balance and gait of Parkinson disease patients – A preliminary study

IntroductionBalance and gait disorders are relevant symptoms in the quality of life of Parkinson's patients. Currently, there is no therapy to reverse or treat this condition. Acupuncture treatment is believed to improve motor ability through the cortico-basal-thalamus-cortical-ganglia. AimTo investigate qualitatively the acute effect of acupuncture on balance and gait in Parkinson's disease in 7 patients. MethodsThis is a randomized and controlled crossover study. The same individual patient was part of both, experimental (real acupuncture) and control group (false acupuncture/sham), and the sequence was randomized. Balance and gait parameters were measured at two different moments, before and after treatment, using four force platforms as well as the collection of 3D markers positions taken by 11 cameras. Images were analyzed using Qualisys Track Manager software that let us extract data related to the quality of gait and balance. ResultsStatistically significant differences were found in gait speed (p = 0.016), gait cadence (p = 0.006), support base width (p = 0.0001), medio-lateral oscillation (p = 0.017), left-right step length (p = 0.0002), and stride length: right-right (p = 0.0000) and left-left (p = 0.0018), time of left support phase (p = 0.029), right support phase (p = 0.025) and double support phase (p = 0.015), between the initial and final moments for the experimental group. Differences in right-left stride length were found for both groups. ConclusionOur results suggest that the acupuncture protocol used objectively could improve gait in Parkinson disease patients. A deep research involving a statistical evaluation supported on a larger number of voluntaries should be accomplished to confirming these promising preliminary results.