5,682 results match your criteria vertical ground


Anisotropic compliance of robot legs improves recovery from swing-phase collisions.

Bioinspir Biomim 2021 Jun 15. Epub 2021 Jun 15.

Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Dr, La Jolla, California, 92093, UNITED STATES.

Uneven terrain in natural environments challenges legged locomotion by inducing instability and causing limb collisions. During the swing phase, the limb releases from the ground and arcs forward to target a secure next foothold. In natural environments leg-obstacle collisions may occur during the swing phase which can result in instability, and may require contact sensing and trajectory re-planning if a collision occurs. Read More

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Comparison of foot strike sound between rearfoot, midfoot and forefoot strike runners.

J Athl Train 2021 Jun 15. Epub 2021 Jun 15.

Gait & Motion Analysis Laboratory, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong.

Context: There are three common foot strike techniques in runners. Whether these techniques generate different sounds at the point of impact with the ground may influence lower limb kinetics. No previous studies have determined whether such relationships exist. Read More

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Chemical control of competing electron transfer pathways in iron tetracyano-polypyridyl photosensitizers.

Chem Sci 2020 Apr 16;11(17):4360-4373. Epub 2020 Apr 16.

Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University Menlo Park California 94025 USA

Photoinduced intramolecular electron transfer dynamics following metal-to-ligand charge-transfer (MLCT) excitation of [Fe(CN)(2,2'-bipyridine)] (), [Fe(CN)(2,3-bis(2-pyridyl)pyrazine)] () and [Fe(CN)(2,2'-bipyrimidine)] () were investigated in various solvents with static and time-resolved UV-Visible absorption spectroscopy and Fe 2p3d resonant inelastic X-ray scattering (RIXS). This series of polypyridyl ligands, combined with the strong solvatochromism of the complexes, enables the MLCT vertical energy to be varied from 1.64 eV to 2. Read More

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Relationship between vertical stratification and feeding habits of mosquito (Diptera: Culicidae) assemblages collected in conservation units in the green belt of the city of São Paulo, Brazil.

Acta Trop 2021 Jun 11:106009. Epub 2021 Jun 11.

Department of Epidemiology, School of Public Health, University of São Paulo, São Paulo, SP, Brazil. Electronic address:

São Paulo is one of the largest cities in the world and has several characteristics that favor a diversity of urban and wild mosquitoes. Little is known about how variations in mosquito diversity and feeding preferences for different hosts in different vegetation strata can influence the risk of pathogen transmission to humans. We investigated vertical stratification of mosquitoes and its relationship with vertebrate hosts in environments with different degrees of conservation in two conservation units in the city of São Paulo. Read More

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Noncontact Knee Ligament Injury Prevention Screening in Netball: A Clinical Commentary with Clinical Practice Suggestions for Community-Level Players.

Authors:
Nicholas C Clark

Int J Sports Phys Ther 2021 Jun 1;16(3):911-929. Epub 2021 Jun 1.

University of Essex.

Netball is a predominantly female team court-sport which is played worldwide. Netball is becoming more popular in the United States following its countrywide introduction to schools and community centers. A unique characteristic of netball is the footwork rule which restricts players to a one-step landing after catching the ball. Read More

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Recommendations for Plyometric Training after ACL Reconstruction - A Clinical Commentary.

Int J Sports Phys Ther 2021 Jun 1;16(3):879-895. Epub 2021 Jun 1.

Education & Research Department, Isokinetic Medical Group, FIFA Medical Centre of Excellence, Bologna, Italy.

This paper presents a four-stage plyometric program to be undertaken as part of criterion-based rehabilitation for athletes with anterior cruciate ligament reconstruction (ACLR). After ACLR, the patient experiences alterations of joint mobility, gait and movement patterns, neuromuscular function and general physical fitness. Plyometric training is an important component for neuromuscular and movement re-conditioning after ACLR. Read More

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Evaluating Sentinel-5P TROPOMI tropospheric NO column densities with airborne and Pandora spectrometers near New York City and Long Island Sound.

Atmos Meas Tech 2020 Nov;13(11):6113-6140

Office of Research and Development, United States Environmental Protection Agency, Triangle Research Park, NC 27709, USA.

Airborne and ground-based Pandora spectrometer NO column measurements were collected during the 2018 Long Island Sound Tropospheric Ozone Study (LISTOS) in the New York City/Long Island Sound region, which coincided with early observations from the Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) instrument. Both airborne- and ground-based measurements are used to evaluate the TROPOMI NO Tropospheric Vertical Column (TrVC) product v1.2 in this region, which has high spatial and temporal heterogeneity in NO. Read More

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November 2020

Effects of additional load at different heights on gait initiation: A statistical parametric mapping of center of pressure and center of mass behavior.

PLoS One 2021 11;16(6):e0242892. Epub 2021 Jun 11.

Physical Education Department, Federal University of São Carlos, São Carlos, Brazil.

The purpose of this study was to investigate the effects of different vertical positions of an asymmetrical load on the anticipatory postural adjustments phase of gait initiation. Sixty-eight college students (32 males, 36 females; age: 23.65 ± 3. Read More

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Evaluating annoyance mitigation in the screening of train-induced noise and ground vibrations using a single-leaf traffic barrier.

Sci Total Environ 2021 May 29;790:147877. Epub 2021 May 29.

Department of Civil and Architectural Engineering, Aarhus, Aarhus University, Denmark.

External sources such as traffic and construction work cause noise and vibration in nearby buildings, potentially annoying human residents. Today, almost every fifth European is harmfully affected by traffic noise and vibration. Wave barriers placed on or embedded within the soil between the source and the receiver can mitigate the transmission of ground vibration, and the airborne noise transmission can be reduced in a similar manner with a screen acting as a noise barrier. Read More

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Evaluation of force feedback in walking using joint torques as 'naturalistic' stimuli.

J Neurophysiol 2021 Jun 9. Epub 2021 Jun 9.

Department of Biological Cybernetics, grid.7491.bBielefeld University, Germany.

Control of adaptive walking requires the integration of sensory signals of muscle force and load. We have studied how mechanoreceptors (tibial campaniform sensilla) encode 'naturalistic' stimuli derived from joint torques of stick insects walking on a horizontal substrate. Previous studies showed that forces applied to the legs using the mean torque profiles of a proximal joint were highly effective in eliciting motor activities. Read More

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Gait asymmetries are exacerbated at faster walking speeds in individuals with acute anterior cruciate ligament reconstruction.

J Orthop Res 2021 Jun 8. Epub 2021 Jun 8.

School of Kinesiology, University of Michigan, Ann Arbor, Michigan, USA.

Previous research suggests more biomechanically demanding tasks (e.g., stair descent, hopping) magnify biomechanical asymmetries compared with walking after anterior cruciate ligament (ACL) reconstruction. Read More

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Assessing responses of phytoplankton to consecutive typhoons by combining Argo, remote sensing and numerical simulation data.

Sci Total Environ 2021 May 29;790:148086. Epub 2021 May 29.

College of Oceanography, Hohai University, Nanjing 210098, China.

Typhoons can affect various hydrodynamic processes, such as upwelling, vertical mixing, and entrainment, which in turn influence the growth and redistribution of phytoplankton. In this study, responses of phytoplankton to consecutive typhoons Barijat and Mangkhut in summer 2018 in the northern South China Sea (NSCS) were investigated through combining remote sensing, numerical simulation, and Argo profile data. Variations of physical and biological properties induced by Barijat and Mangkhut over the study region were observed. Read More

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Computer-aided identification of degenerative neuromuscular diseases based on gait dynamics and ensemble decision tree classifiers.

PLoS One 2021 4;16(6):e0252380. Epub 2021 Jun 4.

Department of Electrical and Computer Engineering, Abu Dhabi University, Abu Dhabi, UAE.

This study proposes a reliable computer-aided framework to identify gait fluctuations associated with a wide range of degenerative neuromuscular disease (DNDs) and health conditions. Investigated DNDs included amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and Huntington's disease (HD). We further performed a statistical and classification comparison elucidating the discriminative capability of different gait signals, including vertical ground reaction force (VGRF), stride duration, stance duration, and swing duration. Read More

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Prophylactic ankle supports effects on time to stabilization, perceived stability and ground reaction force during lateral landing in female collegiate athletes with chronic ankle instability.

BMC Sports Sci Med Rehabil 2021 Jun 3;13(1):62. Epub 2021 Jun 3.

Department of Sports Rehabilitation, Faculty of Sport Science, Arak University, Arak, Iran.

Background: This study was designed to investigate effects of Kinesiotape (KT) with closed basket weave method and lace-up braces (LB) on the vertical time to stabilization, peak vertical ground reaction force (PvGRF), and time to PvGRF as well as perceived stability during lateral landing of participants with chronic ankle instability before and after fatigue.

Methods: Thirty female college athletes with chronic ankle instability of three conditions (control, KT, and LB) performed lateral landing from a 30 cm high step on the plantar pressure platform pre and post fatigue.

Results: The pre-test findings on the rearfoot, of LB indicated negatively increased the PvGRF force (F=3. Read More

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Does Passing Return-to-Sport Criteria Coincide with Normalized Landing Biomechanics in Young Athletes Following Primary Anterior Cruciate Ligament Reconstruction?

J Orthop Res 2021 Jun 3. Epub 2021 Jun 3.

Sports Medicine Research Institute, Ohio State University Wexner Medical Center, Columbus, OH.

We sought to evaluate the sagittal plane knee joint loading patterns during a double-leg landing task among young athletes who passed or failed return-to-sport (RTS) criteria following ACL reconstruction (ACLR), and in uninjured athletes. Participants completed quadriceps strength testing, a hop test battery, and the International Knee Documentation Committee subjective form following medical RTS clearance. ACLR participants 'passed' RTS criteria (RTS-PASS) if they met >90 limb symmetry (%) or score on all measures and were categorized as 'failing' (RTS-FAIL) if not. Read More

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Jumping in Ballet: A Systematic Review of Kinetic and Kinematic Parameters.

Med Probl Perform Art 2021 Jun;36(2):108-128

Royal Opera House, Bow Street, London WC2E 9DD, UK.

Aims: Understanding the biomechanics of jumping in ballet dancers provides an opportunity to optimize performance and mitigate injury risk. This systematic review aimed to summarize research investigating kinetics and kinematics of jumping in ballet dancers.

Methods: PubMed (MEDLINE), SPORTDiscus, and Web of Science were systematically searched for studies published before December 2020. Read More

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Uneven running: how does trunk-leaning affect the lower-limb joint mechanics and energetics?

Eur J Sport Sci 2021 Jun 2:1-20. Epub 2021 Jun 2.

Institute of Sports Science, University of Rostock, Rostock, Germany.

This study aimed to investigate the role of trunk posture in running locomotion. Twelve recreational runners ran in the laboratory across even and uneven ground surface (expected 10 cm drop-step) with three trunk-lean angles from the vertical (self-selected, ∼15°; anterior, ∼25°; posterior, ∼0°) while 3D kinematic and kinetic data were collected using a 3D motion-capture-system and two embedded force-plates. Two-way repeated measures ANOVAs (α = 0. Read More

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Running Biomechanics of Adolescents with Autism Spectrum Disoder.

J Biomech Eng 2021 Jun 2. Epub 2021 Jun 2.

Department of Human Movement Sciences, Old Dominion University.

Research examining gait biomechanics of persons with autism spectrum disorder (ASD) has grown significantly in recent years and has demonstrated that persons with ASD walk at slower self-selected speeds and with shorter strides, wider step widths, and reduced lower extremity range of motion and moments compared to neurotypical controls. In contrast to walking, running has yet to be examined in persons with ASD. The purpose of this study was to examine lower extremity running biomechanics in adolescents (13-18-year-olds) with ASD and matched (age, sex, and body mass index) neurotypical controls. Read More

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Data-driven gait analysis for diagnosis and severity rating of Parkinson's disease.

Med Eng Phys 2021 May 26;91:54-64. Epub 2021 Mar 26.

Department of Biomedical Engineering, PSG College of Technology, Coimbatore 641004, India.

Parkinsons disease (PD) is the second most neurodegenerative disease, which results in gradual loss of movements. To diagnose PD in a clinical setting, clinicians generally use clinical manifestations like motor and non-motor symptoms and rate the severity based on unified Parkinsons disease rating scale (UPDRS). Such clinical assessment largely depends on the expertise and experience of the clinicians and it is subjective leading to variation in assessment between clinicians. Read More

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Atmospheric Boundary Layer Wind Profile Estimation Using Neural Networks Applied to Lidar Measurements.

Sensors (Basel) 2021 May 24;21(11). Epub 2021 May 24.

Aerospace Engineering Area, Universidad de León, 24071 León, Spain.

This paper introduces a new methodology for estimating the wind profile within the ABL (Atmospheric Boundary Layer) using a neural network and a single-point near-ground measurement. An important advantage of this solution when compared with others available in the literature is that it only requires near surface measurements for the prognosis once the neural network is trained. Another advantage is that it can be used to study the wind profile temporal evolution. Read More

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Change of Direction Speed and Technique Modification Training Improves 180° Turning Performance, Kinetics, and Kinematics.

Sports (Basel) 2021 May 24;9(6). Epub 2021 May 24.

Directorate of Sport and Psychology, University of Salford, Greater Manchester M6 6PU, UK.

This study aimed to examine the effects of change of direction (COD) speed and technique modification training on 180° turning performance (completion time, ground contact time [GCT], and exit velocity), kinetics, and kinematics. A non-randomised 6 week intervention study was administered. Thirteen male multidirectional sport athletes formed the intervention group (IG), participating in two COD speed and technique modification sessions per week. Read More

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Minimum Clearance Distance in Fall Arrest Systems with Energy Absorber Lanyards.

Int J Environ Res Public Health 2021 May 28;18(11). Epub 2021 May 28.

Civil Engineering Department, University of Alicante, 03690 Alicante, Spain.

Accidents due to falls from height are one of the main causes of death in workplaces. Fall arrest systems (FAS) are designed to arrest the fall safely without injuring the accident victim. Their main mission is to restrain the body so as to prevent it from hitting the ground, generating forces and accelerations in the arrest process that are not harmful. Read More

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A Simulation Case Study of Knee Joint Compressive Stress during the Stance Phase in Severe Knee Osteoarthritis Using Finite Element Method.

Medicina (Kaunas) 2021 May 30;57(6). Epub 2021 May 30.

Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami-machi, Inashiki 300-0394, Japan.

: Medial knee osteoarthritis is known to increase the mechanical load on the medial compartment of the knee joint during walking; however, it is not visually understood how much the mechanical load increases nor where in the medial compartment of the knee joint that load is focused. Therefore, we conducted a simulation study to determine the location and amount of the mechanical load in the medial compartment of the knee joint during the stance phase. : Subject was a patient with right medial knee osteoarthritis. Read More

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Vertical Jumping for Legged Robot Based on Quadratic Programming.

Sensors (Basel) 2021 May 25;21(11). Epub 2021 May 25.

School of Mechatronical Engineering, Intelligent Robotics Institute, Beijing Institute of Technology, Beijing 100081, China.

The highly dynamic legged jumping motion is a challenging research topic because of the lack of established control schemes that handle over-constrained control objectives well in the stance phase, which are coupled and affect each other, and control robot's posture in the flight phase, in which the robot is underactuated owing to the foot leaving the ground. This paper introduces an approach of realizing the cyclic vertical jumping motion of a planar simplified legged robot that formulates the jump problem within a quadratic-programming (QP)-based framework. Unlike prior works, which have added different weights in front of control tasks to express the relative hierarchy of tasks, in our framework, the hierarchical quadratic programming (HQP) control strategy is used to guarantee the strict prioritization of the center of mass (CoM) in the stance phase while split dynamic equations are incorporated into the unified quadratic-programming framework to restrict the robot's posture to be near a desired constant value in the flight phase. Read More

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Acute Effects of Handheld Loading on Standing Broad Jump in Youth Athletes.

Int J Environ Res Public Health 2021 May 10;18(9). Epub 2021 May 10.

Graduate Institute of Sport Coaching Science, Chinese Culture University, Taipei 11114, Taiwan.

The study aimed to investigate the acute effects of handheld loading on standing broad jump (SBJ) performance and biomechanics. Fifteen youth male athletes (mean age: 14.7 ± 0. Read More

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Horizontal-to-Vertical Spectral Ratio of Ambient Vibration Obtained with Hilbert-Huang Transform.

Sensors (Basel) 2021 May 10;21(9). Epub 2021 May 10.

Department of Biology and Geology, University of Almería, Carretera Sacramento s/n, La Cañada de San Urbano, 04120 Almería, Spain.

The Horizontal-to-Vertical Spectral Ratio (HVSR) of ambient vibration measurements is a common tool to explore near surface shear wave velocity (Vs) structure. HVSR is often applied for earthquake risk assessments and civil engineering projects. Ambient vibration signal originates from the combination of a multitude of natural and man-made sources. Read More

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Focused Patterning of Electrospun Nanofibers Using a Dielectric Guide Structure.

Polymers (Basel) 2021 May 7;13(9). Epub 2021 May 7.

School of Mechanical Engineering, Chungnam National University, 99 Daehak-Ro, Yuseong-Gu, Daejeon 34134, Korea.

The patterning of electrospun fibers is a key technology applicable to various fields. This study reports a novel focused patterning method for electrospun nanofibers that uses a cylindrical dielectric guide. The finite elements method (FEM) was used to analyze the electric field focusing phenomenon and ground its explanation in established theory. Read More

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Estimating Player Positions from Padel High-Angle Videos: Accuracy Comparison of Recent Computer Vision Methods.

Sensors (Basel) 2021 May 12;21(10). Epub 2021 May 12.

Engineering School (ETSEIB), ViRVIG, Universitat Politècnica de Catalunya-BarcelonaTech, Avda. Diagonal 647, 08028 Barcelona, Spain.

The estimation of player positions is key for performance analysis in sport. In this paper, we focus on image-based, single-angle, player position estimation in padel. Unlike tennis, the primary camera view in professional padel videos follows a de facto standard, consisting of a high-angle shot at about 7. Read More

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The Association between Maternal Stress and Glucocorticoid Rhythmicity in Human Milk.

Nutrients 2021 May 11;13(5). Epub 2021 May 11.

Department of Pediatric Endocrinology, Emma Children's Hospital, Amsterdam University Medical Centers, location VUmc, 1081 HV Amsterdam, The Netherlands.

Background: Chronic stress is often accompanied by alterations in the diurnal rhythm of hypothalamus-pituitary-adrenal activity. However, there are limited data on the diurnal rhythmicity of breast milk glucocorticoids (GCs) among women with psychological distress. We compared mothers who sought consultation at an expertise center for pregnant women with an increased risk of psychological distress with control mothers for GC diurnal rhythmicity in milk and saliva obtained at the same time. Read More

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Lower Limb Force Asymmetries During Landing and Jumping Exercises: A Pilot Study.

Int J Exerc Sci 2021 1;14(1):544-551. Epub 2021 Apr 1.

Department of Human Performance and Health Education, Western Michigan University, Kalamazoo, MI, USA.

Significant asymmetries can exist between the lower limbs' force production during the take-off phase of bilateral jumping exercises. Some studies have indicated that similar asymmetries can also exist during the landing phase. It has not been demonstrated if the magnitude of lower body asymmetry was similar between the landing (L) and take-off (TO) phases of bilateral jumping movements. Read More

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