Single Support Research Articles

On the clinical interpretation of overground gait stability indices in children with cerebral palsy

Several indices have been devised to quantify a person’s stability from its gait pattern during overground walking. However, clinical interpretation of the indices is difficult because the link between being stable and adopting a mechanically stable gait pattern may not be straightforward. This is particularly true for one of these indices, the margin of stability, for which opposite interpretations are available in the literature. We collected overground walking data in two groups of 20 children, with unilateral cerebral palsy (CP) and typically developing (TD), for two conditions, on flat and on uneven grounds (UG). We postulated that TD children were more stable during gait than children with CP and that both groups were more stable on flat compared to UG. We explored the coherent association between several indices and the two postulates to clarify clinical interpretation. Our results showed that increased margin of stability, increased amplitude of the whole-body angular momentum, decreased duration of single limb support, increased variability (gait kinematics, step length, and step width) were associated with reduced stability for both postulates. However, results for the margin of stability were paradoxical between the sides in the CP group where small margin of stability was indicative of a fall forward strategy on the affected side rather than improved stability. Whole-body angular momentum and duration of single limb support appeared as the most sensitive indices. However, walking speed influenced these and would need to be considered when comparing groups of different walking speed.

Unveiling the Potential of Heterogeneous Systems for Reversible Hydrogen Storage in Liquid Organic Hydrogen Carriers.

Transitioning towards a carbon-free economy is the current global need of the hour. The transportation sector is one of the major contributors of CO2 emissions in the atmosphere disturbing the delicate balance on the Earth, leading to global warming. Hydrogen has emerged as a promising alternative energy carrier capable of replacing fossil fuels, with advancements in systems facilitating its storage and long-distance transport. In this context, the concept of liquid organic hydrogen carriers (LOHCs) is taking the lead, offering a plausible solution because of its compatibility with the existing gasoline infrastructure, while eliminating the challenges associated with conventional hydrogen storage methods. Key LOHC systems, such as methylcyclohexane/toluene and H-18-dibenzyltoluene/dibenzyltoluene (H-18-DBT/DBT), have been extensively researched for large-scale applications. However, challenges persist, particularly concerning the endothermic nature of the reactions involved. In this regard, of particular interest are the multifunctional heterogeneous catalysts supported on a single support, offering cost-effective and energy-efficient solutions to circumvent issues related to the endothermicity of the reactions. In this review, solid heterogeneous catalysts that have been developed and investigated for reversible dehydrogenation and hydrogenation reactions have been presented. These catalysts include monometallic, bimetallic, and pincer complexes supported on materials designed for efficient hydrogen uptake and release.

Effect of adapted dance program on gait in adults with cerebral palsy: a pilot study.

The gait function in adults with cerebral palsy (CP) deteriorates rapidly with age. Dance has been used as an effective intervention to improve balance, postural control, and gait. This study aimed to investigate the feasibility and effects of an adapted dance program (ADP) on the gait in adults with CP. The ADP, which consists of floor and barre workouts, was designed to be adapted for individuals with CP. Ten female adults with spastic diplegic CP (mean age 52.3 ± 6.34, Gross Motor Function Classification System level II) participated in this study. Outcome measures, examined using 3D gait analysis, included spatiotemporal gait parameters and the Gait Deviation Index (GDI) based on nine kinematic variables in all planes of motion. To assess feasibility, we conducted post-questionnaires and a group interview. The ADP, each lasting 90 min, was held twice per week for 12 weeks. A statistically significant improvement was observed in GDI (Δ5.74 points, p = 0.014), with a large effect size (d = 0.76). Foot off (Δ-0.72%), first double support (Δ-0.2%), second double support (Δ1.5%), and single support (Δ0.64%) showed no significant differences. Step length (Δ1.48 cm), cadence (Δ3.95 steps/min), and walking speed (Δ6.41 cm/s) tended to increase, though the differences were not statistically significant. Participants expressed high levels of physical and emotional satisfaction, suggesting a need for early intervention. The ADP may improve gait patterns in adults with spastic diplegic CP. The feasibility results indicated that the ADP is suitable for adults with spastic diplegic CP. This study provides evidence for improvement in gait patterns through dance, which has not been reported in previous dance studies on individuals with CP, offering additional information on the benefits of dance.

Gait stability improves following unilateral total ankle arthroplasty.

End-stage ankle arthritis is often treated surgically by total ankle arthroplasty (TAA) due to its potential to improve gait through increased joint range of motion and reduce pain. However, TAA's effect on gait stability is not well understood. This study explores the impact of TAA on gait stability, measured by Margin of Stability (MoS), in 148 patients with end-stage ankle arthritis. Kinematic data were collected pre-operatively, at 1-year post-op, and at 2-years post-op and the MoS was determined at heel strike and midstance for the anteroposterior (MoSAP) and mediolateral (MoSML) directions. A linear mixed effects model including gait speed as a factor was used to assess the effects of limb, session, and their interaction on outcome measures. A significant interaction (p < 0.002) between limb (surgical, nonsurgical) and session (pre-op, 1-year post-op, 2-years post-op) was identified for each MoS variable of interest. Cumulatively, our results suggest that the nonsurgical limb, MoSAP at heel strike and MoSML at midstance improved (increased) as time from surgery increased. These results suggest patients developed a compensatory movement pattern to navigate surgical limb single support. TAA reduces this compensation improving side-to-side symmetry, while not fully restoring symmetry by 2-years post-op. These results indicate that TAA could improve gait stability in patients with end-stage ankle arthritis, but further work is needed to understand the impact of TAA on altering fall risk.

Analysis of Biomechanical Gait Parameters in Patients after Total Hip Replacement in the Early Recovery Period

INTRODUCTION. The widespread use of total hip arthroplasty (THA) places high demands on the restoration of a normal gait pattern and is one of the key goals of rehabilitation. AIM. Determination of key parameters of walking in patients after THA to assess the effectiveness of restoration of the physiological gait pattern. MATERIALS AND METHODS. In a control prospective study, the main group consisted of 23 patients (11 men, 12 women, aged from 41 to 75 years, mean age 63.9 ± 9.4 years), who in the first 8 weeks after planned THA, moved with the help of assistive devices. supports (two crutches or walkers) who underwent stage II of medical rehabilitation; control group — 27 healthy people (12 men and 15 women, aged from 42 to 73 years, average age 60.9 ± 9.9 years). Spatiotemporal and kinematic gait parameters were recorded before and after the rehabilitation course using a gait simulator with biofeedback equipped with three sensors. For each leg, spatiotemporal and kinematic biomechanical parameters were separately recorded. RESULTS. All spatiotemporal gait parameters on both limbs and pelvic mobility in the sagittal plane in patients in the early recovery period after THA before the start of the rehabilitation course are significantly different from healthy people. After a course of rehabilitation, the studied gait parameters approach physiological values. The main asymmetry is observed in the single support phase from 16 % at the beginning of the course, to 10 % at the end; sagittal pelvic mobility are 2 times higher than the physiological normal meaning at the beginning of the course, without significant changes in dynamics. DISCUSSION. Disturbances in the gait pattern are observed in the majority of patients undergoing THA. Step symmetry is one of the significant parameters of walking, according to which the primary global assessment of its quality is carried out. Asymmetry of the single support phase of the limbs is a natural development of compensatory motor reactions after endoprosthetics. CONCLUSION. The gait parameters “step frequency” and “step cycle” quickly change after a course of rehabilitation and can be used to assess the locomotor activity of patients during short courses of medical rehabilitation in the early recovery period. Indicators of stance and swing phases, their symmetry changes much more slowly, can serve as criteria for assessing the effectiveness of measures taken at the stages of rehabilitation in the dynamics of gait restoration.

Characteristics of gait function in hemiparetic patients with subacute period of ischemic stroke: a single-center retrospective study

BACKGROUND: Gait disorders are common among 80% of stroke patients. Its consequences include increased risk of falls and functional limitations, which can significantly reduce the quality of life. AIM: To investigate the functional profile of hemiparesis resulting from subacute ischemic stroke. MATERIALS AND METHODS: This observational, retrospective, one-stage, single-center study analyzed primary biomechanical gait parameters in 31 patients and 34 healthy controls. Spatial, temporal, kinematic, and electromyographic characteristics were recorded. A statistical assessment and inter-group and intra-group comparison of the collected data were performed to identify the pathognomonic features of hemiplegic gait in patients with subacute stroke. RESULTS: Changes in gait biomechanics typical for hemiparetic patients who have suffered from ischemic stroke were described: slight asymmetry of step cycle, normal duration of support period on the paretic side, significant increase in duration of support period on the healthy side, and shortening of single support period on the paretic side. Additionally, the asymmetry of the walking function was characterized by changes in reciprocity, that is, a harmonious sequence of step cycles. The function of the hip and knee joints was reduced and altered, and the amplitude of the ankle joint was increased. Decrease and change in the bioelectric activity profile of muscles were detected. Moreover, the quadriceps femoris function was least affected. CONCLUSION: The main changes in walking function are characterized by an asymmetry of spatiotemporal parameters, a decrease in movement amplitudes of the hip and knee joints on the paretic side, an increase in ankle joint amplitude, a decrease in the bioelectric activity of muscles, and a shift in the phases of their activity. The results contribute to a better understanding of the mechanisms behind hemiplegic gait and provide a valuable tool for developing more personalized and targeted rehabilitation plans for patients suffering from hemiparesis as a result of subacute ischemic stroke.

Gait coordination control of bipedal modular reconfigurable robot based on adaptive neural network

This paper proposed an adaptive neural network (NN) control method to track the desired trajectory of a bipedal modular reconfigurable robot (MRR), which can solve the gait coordination problem of bipedal MRR. The leg dynamic model and the body dynamic model of bipedal MRR are established based on the Newton–Euler iterative method, and the global dynamic model is subsequently established. Aiming at the gait coordination problem between double support phase (DSP) and single support phase (SSP), the desired trajectory is generated based on the zero-moment point (ZMP) method. The adaptive NN controller is designed to track the generated desired trajectory, which also compensates interconnected dynamic coupling (IDC) effects of the bipedal MRR. The stability of bipedal MRR system is proved by Lyapunov theory. In the end, the effectiveness of the control method is verified by comparative simulation. The simulation results show that the proposed adaptive NN method reduces the position tracking error by [Formula: see text] and the control torque by [Formula: see text] compared with the existing control methods.

A novel rigid Foot-Ground contact model for Predicting ground reaction forces and center of pressure during normal gait

Ground reaction forces (GRFs) and center of pressure (COP) are essential for understanding human motion and evaluating biomechanical parameters, but measuring them with force plates is often limited in many scenarios. In this study, we propose a novel methodology for estimating GRFs and COP during normal gait based on a rigid foot–ground contact model, referred to as the COP phase transition continuity model (COP-PTCM). The GRFs and COP are calculated based on the Newton-Euler Equations during the single support phase (SSP). Considering the spatiotemporal continuity of the COP trajectory during normal gait, the COP data for the double support phase (DSP) is obtained by an improved logistic function fitted using the COP data from the SSP. GRFs during the DSP are optimized using the minimum energy hypothesis. The COP-PTCM method is used to estimate the GRFs and COP of ten participants during normal gait, and the results are compared with simultaneously measured force plate data, yielding the relative root mean square error (rRMSE) between measured and estimated GRFs in the anterior-posterior, vertical, and medial–lateral directions are 10.90 ± 2.09 %, 4.73 ± 1.44 %, and 15.17 ± 1.69 %, respectively. Additionally, the rRMSE between measured and estimated COP in the anterior-posterior direction is 11.23 ± 0.03 %. The above comparison validates the effectiveness and accuracy of the proposed method.

Gait pathology presented with developmental dysplasia of the hip: a control case study

A well-known and long-term complication of developmental dysplasia of the hip (DDH) is improper gait pattern, early regressive joint disorder, and permanent pain. It can affect the family's psychological, social, and functional parts. This study planned to resolve foot posture and gait analysis across patients with developmental hip dysplasia and correlate it with the control group. Case-control studies determine the main results. We correlated the gait analysis results on the Zebris FDM platform. The case included candidates with DDH under conservative treatment with an abduction brace and a control group with healthy participants. This study was conducted at King Abdullah Specialized Children Hospital, Riyadh, in the Kingdom of Saudi Arabia. This research enclosed 445 outcomes with DDH and 168 for the control category. The Sign test presented a significant diversity in Zebris FDM outcomes between DDH and the control group, especially in left foot external rotation with a p-value of 0.01 (left hip mean of 4.53, n=445, SD 8.78). A significant variation was present in step width, stance phase on both legs, single support, load response, swing phase, pre-swing, and a double support p-value of 0.00 (p&lt;0.05). W-sitting was preferred in 256 (n=445, 58%) of the DDH results and by 61 (n=168, 36%) from the control group. This study's outcomes presented a greater risk of pronation on the left foot and gait alteration on the right lower limb. The gait investigation presented a clear description of its patterns in paediatrics with DDH. Analyzing the gait among the DDH and the control group demonstrated a variation in each gait outcome from Zebris FDM platform software. DDH has a negative response on the gait pattern and foot posture, this is a great consequence presented in connection with Saudi applicants. Keywords: FDM, DDH, gait, control group, Kingdom of Saudi Arabia

Gait Generation of a 10-DOF Humanoid Robot on Deformable Terrain Based on Spherical Inverted Pendulum Model

Abstract Gait generation of a humanoid robot on deformable terrain is a complex problem as the foot and terrain interaction and terrain deformation has to be included in the dynamics. In order to simplify the dynamics of walk on deformable terrain, we used a spherical inverted pendulum (SIP) to represent the single support phase, in which the effect of terrain deformation is represented by a spring and damper contact model. The impact model for leg transition is derived from angular momentum conservation. In order to minimize the energy loss due to impact, the double support phase is modeled as a suspended pendulum. Based on the motion of the SIP model, the hip and leg trajectories of a 10 DOF humanoid robot are generated. The joint angles of the humanoid are obtained from inverse kinematics. The motion of the center of mass is analyzed by inverse dynamics of a floating-base robot. The proposed gait generation method has been experimentally validated using a Kondo KHR-3HV humanoid robot on deformable terrain. The results show that the humanoid can effectively track the trajectories of the SIP model.

Insights into the Single Atom and Support Interaction in Electrocatalytic Oxygen Evolution Reaction

Insights into the Single Atom and Support Interaction in Electrocatalytic Oxygen Evolution Reaction

Rotation of the hammer and performance in hammer throwing.

The purpose of this study was to determine the effects of hammer rotation on performance in hammer throwing. The hammer's velocity increment at different stages, the duration of rotations at different phases, and the horizontal azimuth angle and rotation radius at critical instants were calculated and compared between the long and short trials for 26 female athletes in actual competitions. Compared to short trials, female throwers' long trials exhibited significantly larger release velocity (p < 0.001, ES = 1.42), greater velocity increment during the double support phase (p = 0.006, ES = 0.59), shorter duration during the single support phase (p ≤ 0.043, ES = 0.42-0.83), lower horizontal azimuth angle (p ≤ 0.027, ES = 0.46-0.57), and longer rotational radius at critical instants (p ≤ 0.021, ES = 0.48-0.73). During the process from the hammer head's low point to high point, athletes should focus on increasing the rotation radius of the hammer head and accelerating the right foot's landing speed during the single support phase. This approach aims to reduce the hammer's horizontal azimuth angle at the right foot touchdown, enhance the acceleration performance during the double support phase, and increase the release speed.

Healthy older adults generate transverse-plane momenta required for 90° turns while walking during the same phases of gait as used in straight-line gait

BackgroundGeneration and regulation (control) of linear and angular momentum is a challenge during turning while walking which may be exacerbated by age-related changes. In healthy older adults, little is known about how momentum is controlled during turns, especially within each phase of gait. Each phase of gait affords unique mechanical contexts to control momenta and regulate balance. In healthy young adults, we found that the transverse-plane linear and angular momenta generation strategies observed within specific phases of gait during straight-line gait were also used during turns. Therefore, in this study, we investigated whether healthy older adults shared similar momentum control strategies specific to each gait phase during straight-line gait and turns.MethodsNine healthy older adults completed straight-line gait and 90° leftward walking turns. We compared the change in transverse-plane whole-body linear and angular momentum across gait phases (left and right single and double support). We also compared the average leftward force and transverse-plane moment across gait phases.ResultsWe found that leftward linear momentum was generated most during right single support in straight-line gait and leftward turns. However, in contrast to straight-line gait, during leftward turns, average leftward force was applied across gait phases, with left single support generating significantly less leftward average force than other gait phases. Leftward angular momentum generation and average moment were greatest during left double support in both tasks. We observed some within-participant results that diverged from the group statistical findings, illustrating that although they are common, these momenta control strategies are not necessary.ConclusionsOlder adults generated transverse-plane linear and angular momentum during consistent phases of gait during straight-line gait and 90° turns, potentially indicating a shared control strategy. Understanding momentum control within each phase of gait can help design more specific targets in gait and balance training interventions.

Co-immobilization of magnesium precursor and Candida rugosa lipase on alumina via covalent bonding for biodiesel production

Catalyst development is one of the most challenging aspects in biodiesel production due to the compatibility issue with the feedstocks and catalyst poisoning upon exposure to process conditions. In the present research, chemoenzymatic catalyst was prepared by impregnation of magnesium aluminate (MA) on alumina support, modifying the support using activating agent, and immobilization of Candida rugosa lipase (CRL) onto the support. The optimum immobilization condition was resulting in 85.07 % of activity recovery of immobilized lipase, equivalent to 30.53 % of immobilization efficiency. The catalysts were characterized through XRD, FTIR, FESEM-EDX, NAA and CO2-TPD confirming the mixture of AlO(OH), magnesium aluminate (MA), (MgNO3)2 and Mg2+ on the support. CRL/L-lysine/MA showed remarkable improvement in thermal stability (40 − 70℃), solvents tolerance (ethanol, methanol, isopropanol, tert-butanol), and storage stability at 30 ℃, as compared to free CRL. CRL/L-lysine/MA successfully produced biodiesel yield up to 87.10 % at 200.71 rpm of agitation speed, 13.58 % (w/w) of water content, 10 h reaction time, 15 % (w/w) of catalyst loading, at 50 ℃, using 1:12 of oil to methanol molar ratio, and retaining 46.60 % of biodiesel yield after six cycle. The CRL/L-lysine/MA demonstrated novel catalysts characteristics comprising chemical and biological active species on a single support for biodiesel production from waste cooking oil (WCO).

Influence of regularly repeated asymmetric load on the locomotor system in sweep rowers

ABSTRACT This study aims to objectively evaluate the trunk posture of sweep rowers (bow-side rowers/stroke-side rowers) and compare the results with scull rowers and non-rowing controls. Sixty-four healthy individuals divided into four groups were assessed using a DIERS formetric III 4D device that is based on a method of moiré topography. There were seven parameters observed in an assessment of standing posture, and eight parameters were studied for an evaluation of posture during the gait cycle. In comparison with non-rowing controls and scull rowers, stroke-side rowers showed significantly greater rotational deviation of the trunk at the L3 vertebra level and a greater magnitude of scoliosis angle during walking throughout the single support phase on the left leg (p < 0.05). Stroke-side rowers also demonstrated greater magnitude of scoliosis angle than non-rowing controls in double support phase in the transition from the left to the right leg (p < 0.05). Moreover, as opposed to non-rowing controls, stroke-side rowers and scull rowers showed significantly greater values of coronal imbalance (p < 0.05). Bow-side rowers differed from non-rowing controls and scull rowers in a significantly greater magnitude of scoliosis angle throughout the single support phase on the left leg (p < 0.05). Trial registration number: clinicaltrials.gov (identifier: NCT05685563).

Quantitative Research on Roof Deformation and Temporary Support Stiffness in Deep-Mine Gob-Side Entry Retaining by Roof Cutting

The important technical process to ensure the success of gob-side entry retaining by roof cutting (GERRC) was the advanced pre-splitting blasting to cut off the mechanical connection between the roadway and working face roof. The whole-cycle roof structure evolution and stress characteristics of GERRC were analyzed. The factors affecting the roof deformation of GERRC were analyzed, and the quantitative relationship between the roof deformation of GERRC and the support stiffness was determined. The results showed that the temporary support stiffness was higher, the support position to the side of the roof cutting was closer, and the roof subsidence deformation of GERRC was smaller. It is proposed to use a single support mass with a high stiffness to control the deformation of the roof, but it also made the support mass and roof elastic potential energy aggregate. To fully utilize the matching of the support stiffness and roof subsidence, improve the stability, and control the subsidence deformation of the roof in GERRC, double-row stacking supports were adopted in the inclination of GERRC, which were used to increase the stiffness of the support system.

Does a Standardized Load Carriage Increase Spatiotemporal Gait Asymmetries in Police Recruits? A Population-based Study.

Although the effects of carrying loads on gait biomechanics have been well-documented, to date, little evidence has been provided whether such loads may impact spatial and temporal gait asymmetries under the different foot regions. Therefore, the main purpose of the study was to examine the effects of carrying a standardized police equipment on spatiotemporal gait parameters. In this population-based study, participants were 845 first-year police recruits (age: 21.2 ± 2.3 years; height: 178.1 ± 10.2 cm; weight: 78.4 ± 11.3 kg; body mass index: 24.7 ± 3.2 kg/m2; 609 men and 236 women; 72.1% men and 27.9% women) measured in 2 conditions: (i) "no load" and (ii) "a 3.5 kg load." Spatiotemporal gait parameters were derived from the FDM Zebris pressure platform. Asymmetry was calculated as (xright-xleft)/0.5*(xright + xleft)*100%, where "x" represented a given parameter being calculated and a value closer to 0 denoted greater symmetry. When compared to "no load" condition, a standardized 3.5 kg/7.7 lb load significantly increased asymmetries in spatial gait parameters as follows: gait phases of stance (mean diff. = 1.05), load response (mean diff. = 0.31), single limb support (mean diff. = 0.56), pre-swing (mean diff. = 0.22), and swing (mean diff. = 0.90) phase, while no significant asymmetries in foot rotation, step, and stride length were observed. For temporal gait parameters, we observed significant asymmetries in step time (mean diff. = -0.01), while no differences in cadence and gait speed were shown. The findings indicate that the additional load of 3.5 kg/7.7 lb is more likely to increase asymmetries in spatial gait cycle components, opposed to temporal parameters. Thus, external police load may have hazardous effects in increasing overall body asymmetry, which may lead to a higher injury risk and a decreased performance for completing specific everyday tasks.

A dataset of alternately located segments in protein crystal structures

Protein Data Bank (PDB) files list the relative spatial location of atoms in a protein structure as the final output of the process of fitting and refining to experimentally determined electron density measurements. Where experimental evidence exists for multiple conformations, atoms are modelled in alternate locations. Programs reading PDB files commonly ignore these alternate conformations by default leaving users oblivious to the presence of alternate conformations in the structures they analyze. This has led to underappreciation of their prevalence, under characterisation of their features and limited the accessibility to this high-resolution data representing structural ensembles. We have trawled PDB files to extract structural features of residues with alternately located atoms. The output includes the distance between alternate conformations and identifies the location of these segments within the protein chain and in proximity of all other atoms within a defined radius. This dataset should be of use in efforts to predict multiple structures from a single sequence and support studies investigating protein flexibility and the association with protein function.

Metal–Single Atom Support Interactions for Enhancing Proton-Exchange Membrane Fuel Cell Cathode Stability: A Review

Metal–Single Atom Support Interactions for Enhancing Proton-Exchange Membrane Fuel Cell Cathode Stability: A Review

The Immediate Effect of the Novel Hybrid Passive Spring Damper Ankle-Foot Orthosis on Spatiotemporal Parameters of Walking in Patients with Multiple Sclerosis

ABSTRACT Introduction Patients with multiple sclerosis (PwMS) experience damage to their central nervous system, which can lead to unilateral or bilateral drop foot. The presently utilized ankle-foot orthoses (AFOs) for PwMS have exhibited limited clinical efficacy. Objective This current study evaluated the immediate effects of the Novel Hybrid Passive Spring Damper Ankle-Foot Orthosis (HPSDAFO) on walking in PwMS. Study design A cohort trial. Methods Twelve PwMS suffering of unilateral drop foot took part in this study. They were given the novel HPSDAFO and underwent kinematic assessment including walking along a 10-m walkway at a self-selected speed, both with and without the HPSDAFO. Results The novel HPSDAFO device significantly changed gait parameters of ankle range of motion, single limb support duration, and step and stride length of the affected side (P &lt; 0001). Furthermore, the device also improved the symmetry index and resulted in increased walking speed and cadence. Conclusions The application of the novel HPSDAFO on the affected side of PwMS resulted in a notable enhancement in the symmetry of spatial parameters, which highlights the need for additional research in this area. Clinical Relevance Using the novel HPSDAFO, PwMS can walk without adverse effects, promoting the normalization of their spatiotemporal walking parameters.