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Di Wu, Chao Zheng, Ji Wu, Longfeng Wang, Xiang Wei, Lizheng Wang
INTRODUCTION: Knee injuries are common among paratroopers and skydivers during landing maneuvers. The aim of this study was to investigate the effects of dropping height and the use of protective knee braces on parachute landing biomechanics. METHODS: The study cohort consisted of 30 male elite paratroopers with formal parachute landing training and more than 2 yr of parachute jumping experience. Each participant was instructed to jump off a platform at two different heights (40 and 80 cm, respectively) and land on force plates in a half-squat posture...
January 1, 2018: Aerospace Medicine and Human Performance
Arinori Kamono, Mizuki Kato, Naomichi Ogihara
Clarifying the biomechanics of cane-assisted gait in elderly individuals and patients with gait disorders is important for developing better therapeutic interventions in the fields of rehabilitation and orthopedics. However, if the foot and the cane in the ipsilateral hand are placed on the same force plate simultaneously, the force plate cannot separate the forces as it records the sum of the forces. To overcome this indeterminacy problem of the ground reaction force (GRF) and the center of pressure (COP) in cane-assisted gait analysis, a method to partition the GRF and COP using an instrumented cane with a force transducer has been proposed...
November 28, 2017: Gait & Posture
Rong Li, Wei Liao, Yangyang Yu, Heng Chen, Xiaonan Guo, Ye-Lei Tang, Huafu Chen
Benign epilepsy with centrotemporal spikes (BECTS) is characterized by abnormal (static) functional interactions among cortical and subcortical regions, regardless of the active or chronic epileptic state. However, human brain connectivity is dynamic and associated with ongoing rhythmic activity. The dynamic functional connectivity (dFC) of the distinct striato-cortical circuitry associated with or without interictal epileptiform discharges (IEDs) are poorly understood in BECTS. Herein, we captured the pattern of dFC using sliding window correlation of putamen subregions in the BECTS (without IEDs, n = 23; with IEDs, n = 20) and sex- and age-matched healthy controls (HCs, n = 28) during rest...
December 5, 2017: Human Brain Mapping
M C Erlandson, S Hounjet, T Treen, J L Lanovaz
Weight bearing (WB) activity is important for healthy skeletal development. The magnitude of loading during WB activities, especially upper limb impacts, has yet to be quantified in children. This study quantifies ground reaction forces (GRF) experienced by children performing WB activities and examines the contribution of body weight (BW) to GRF. Fifty children, aged 8-12 were recruited (34 males). GRF were measured using force plates during 20 upper and lower limb activities (such as landing on the feet and hands)...
December 4, 2017: Journal of Sports Sciences
B Samadi, M Raison, L Ballaz, S Achiche
Three-dimensional ground reaction forces (3D-GRF) are essential for functional evaluation for rehabilitation. A platform path is required to obtain the 3D-GRF. The main shortcoming of these platform paths is that during double stance phases of gait, both feet can be placed on the same force platform causing the need for decomposing the 3D-GRF under each foot. Despite the high number of studies on force decomposition, there is still no method on the decomposition of 3D-GRF based on data from platforms. OBJECTIVE: This study aims to present an automatic method using parametric curve fitting modeling to increase the accuracy of decomposition of 3D-GRF during double stances under each foot...
December 1, 2017: Journal of Musculoskeletal & Neuronal Interactions
Wing-Kai Lam, Yi Qu, Fan Yang, Roy T H Cheung
Background: Court shoe designs predominantly focus on reducing excessive vertical ground reaction force, but shear force cushioning has received little attention in the basketball population. We aimed to examine the effect of a novel shoe-cushioning design on both resultant horizontal ground reaction forces and comfort perception during two basketball-specific cutting movements. Methods: Fifteen university team basketball players performed lateral shuffling and 45-degree sidestep cutting at maximum effort in basketball shoes with and without the shear-cushioning system (SCS)...
2017: PeerJ
Jørgen Danielsen, Øyvind Sandbakk, David McGhie, Gertjan Ettema
The purpose of this study was to examine the effect of increasing exercise intensity on the role of joint powers in ergometer double poling (DP), while taking specific dynamic constraints into account. One main question was whether lower-body power contribution increased or decreased with increasing intensity. Nine male Norwegian national-level cross-country skiers performed ergometer DP at low, moderate, high and maximal intensity. Kinematics, and ground (GRF) and poling (Fpoling) reaction forces were recorded and used in link segment modeling to obtain joint and whole-body dynamics...
November 23, 2017: Human Movement Science
Rémy Balthazard, Stéphanie Jager, Olivier Ferry, Abdessellam Dahoun, Eric Mortier
PURPOSE: To assess the influence of applicator tip diameter on the inclusion of porosities in three different flowable resin composites. METHODS: The initial porosity of three syringes [Filtek Supreme XTE Flowable (XTE), Grandio Flow (GRF), Gradia Direct Flo (GDF)] was determined by 3D tomography. 25 samples per syringe, i.e. 75 samples in total, were prepared using five applicator tips of different diameters (n= 5). The porosity of the 75 samples was assessed by 3D tomography...
June 2017: American Journal of Dentistry
Heather J Bigham, Teresa E Flaxman, Andrew J J Smith, Daniel L Benoit
BACKGROUND: Females exhibit significantly greater incidence, prevalence, and severity of osteoarthritis (OA) compared to males. Despite known biological, morphological, and functional differences between males and females, there has been little sex-related investigation into sex-specific biomechanical and neuromuscular responses to OA. OBJECTIVE: To identify sex-related differences in OA-affected adults and within-sex differences between healthy and OA-affected adults' muscular activation patterns during lower limb loading...
November 22, 2017: Knee
Vikram A Misra, Yu Wang, Michael P Timko
BACKGROUND: Cowpea (Vigna unguiculata (L.) Walp.) is the most important food and forage legume in the semi-arid tropics of sub-Saharan Africa where approximately 80% of worldwide production takes place primarily on low-input, subsistence farm sites. Among the major goals of cowpea breeding and improvement programs are the rapid manipulation of agronomic traits for seed size and quality and improved resistance to abiotic and biotic stresses to enhance productivity. Knowing the suite of transcription factors (TFs) and transcriptionally active proteins (TAPs) that control various critical plant cellular processes would contribute tremendously to these improvement aims...
November 22, 2017: BMC Genomics
Daan van Kooten, Florentina Hettinga, Kim Duffy, Jo Jackson, Matthew J D Taylor
The variability of the centre of pressure (COP) during walking can provide information in relation to stability when walking. The aim of this study was to investigate if age and sex were associated with COP variability, COP excursions, and COP velocities during walking. One-hundred and fourteen older adults (age 65.1±5.5 yrs.) participated in the study. A Kistler force platform (1000Hz) recorded the ground reaction forces and COPs during walking at a self-selected walking speed. The stance phase was divided, using the vertical GRF, into four sub-phases: loading response (LR), mid-stance (MSt), terminal stance (TSt), and pre-swing (PSw)...
November 13, 2017: Gait & Posture
Nicholas R Heebner, Deirdre M Rafferty, Meleesa F Wohleber, Andrew J Simonson, Mita Lovalekar, Andrew Reinert, Timothy C Sell
CONTEXT:   Several tasks have been used to examine landing biomechanics for evaluation and rehabilitation, especially as related to anterior cruciate ligament injuries. However, comparing results among studies in which different tasks were used can be difficult, and it is unclear which task may be most appropriate. OBJECTIVE:   To compare lower extremity biomechanics across 5 commonly used landing tasks. DESIGN:   Descriptive laboratory study...
November 20, 2017: Journal of Athletic Training
Huan Huang, Yuchao Jiang, Mengqing Xia, Yingying Tang, Tianhong Zhang, Huiru Cui, Junjie Wang, Yu Li, Lihua Xu, Adrian Curtin, Jianhua Sheng, Yuping Jia, Dezhong Yao, Chunbo Li, Cheng Luo, Jijun Wang
Modified electroconvulsive therapy (MECT) has been widely applied to help treat schizophrenia patients who are treatment-resistant to pharmaceutical therapy. Although the technique is increasingly prevalent, the underlying neural mechanisms have not been well clarified. We conducted a longitudinal study to investigate the alteration of global functional connectivity density (gFCD) in schizophrenia patients undergoing MECT using resting state fMRI (functional magnetic resonance imaging). Two groups of schizophrenia inpatients were recruited...
November 6, 2017: Schizophrenia Research
Sang-Joo Lee, Byung Ha Lee, Jae-Hak Jung, Soon Ki Park, Jong Tae Song, Jeong Hoe Kim
We investigated the biological roles of the Arabidopsis thaliana GROWTH-REGULATING FACTOR (GRF) and GRF-INTERACTING FACTOR (GIF) transcriptional complex in the development of gynoecia and anthers. There are nine GRFs and three GIFs in A. thaliana, and seven GRFs are post-transcriptionally silenced by microRNA396 (miR396). We found that overexpression of MIR396 in the gif1 gif2 double mutant background (gif1 gif2 35S:MIR396) resulted in neither ovary nor pollen. Histological and molecular marker-based analyses revealed that the mutant gynoecial primordia failed to develop carpel margin meristems (CMMs) and mature flowers lacked the ovary, consisting only of the stigma, style, and replum-like tissues...
November 7, 2017: Plant Physiology
Moataz Eltoukhy, Christopher Kuenze, Michael S Andersen, Jeonghoon Oh, Joseph Signorile
Kinetic gait abnormalities result in reduced mobility among individuals with Parkinson's disease (PD). Currently, the assessment of gait kinetics can only be achieved using costly force plates, which makes it difficult to implement in most clinical settings. The Microsoft Kinect v2 has been shown to be a feasible clinic-based alternative to more sophisticated three-dimensional motion analysis systems in producing acceptable spatiotemporal and kinematic gait parameters. In this study, we aimed to validate a Kinect-driven musculoskeletal model using the AnyBody modeling system to predict three-dimensional ground reaction forces (GRFs) during gait in patients with PD...
December 2017: Medical Engineering & Physics
Tracey L Clissold, Paul W Winwood, John B Cronin, Mary Jane De Souza
Jumps have been investigated as a stimulus for bone development, however effects of instruction, jump type and jump-landing techniques need investigation. This study sought to identify whether ground reaction forces (GRF's) for bilateral vertical jumps (countermovement jumps and drop jumps) with reactive jump-landings (i.e. jumping immediately after initial jump-landing), with instruction and with instruction withdrawn, achieve magnitudes and rates of strain previously shown to improve bone mass among premenopausal women...
November 1, 2017: Journal of Applied Biomechanics
Eric M Mosier, Andrew C Fry, Michael T Lane
This study examined the kinetic contributions of the upper extremities during counter-movement vertical jumps (CMVJ) while using arm swing (AS) or no-arm swing (NAS) conditions. Fourteen healthy men (X¯±SD; age = 24.1±3.9 yrs) volunteered for this investigation. Subjects performed in random order a total of 6 jumps consisting of 3 AS and 3 NAS CMVJ. A motion capture system was used to analyze the kinetic data. Paired samples t-tests were used to examine the subjects' mean differences in the AS and NAS CMVJ trials (p<0...
October 27, 2017: Journal of Strength and Conditioning Research
Megan A Mickelson, Thao Vo, Alexander M Piazza, Nicola J Volstad, Brett W Nemke, Peter Muir
OBJECTIVE To determine variance effects influencing ground reaction forces (GRFs) in a heterogeneous population of lame dogs during trotting. ANIMALS 30 client-owned dogs with thoracic limb lameness and 31 dogs with pelvic limb lameness. PROCEDURES GRFs, velocity, height at the dorsal aspect of the scapulae (ie, withers), and shoulder height were obtained. Each dog was trotted across a force platform at its preferred velocity. Variance effects for 12 velocity and associated relative velocity (V*) ranges were examined...
November 2017: American Journal of Veterinary Research
Jessica McDonnell, John D Willson, Kevin A Zwetsloot, Joseph Houmard, Paul DeVita
The inherit injury risk associated with high-impact exercises calls for alternative ways to achieve the benefits of aerobic exercise while minimizing excessive stresses to body tissues. Skipping presents such an alternative, incorporating double support, flight, and single support phases. We used ground reaction forces (GRFs), lower extremity joint torques and powers to compare skipping and running in 20 healthy adults. The two consecutive skipping steps on each limb differed significantly from each other, and from running...
October 7, 2017: Journal of Biomechanics
Chih-Yuan Hong, Lan-Yuen Guo, Rong Song, Mark L Nagurka, Jia-Li Sung, Chen-Wen Yen
By incorporating force transducers into treadmills, force platform-instrumented treadmills (commonly called force treadmills) can collect large amounts of gait data and enable the ground reaction force (GRF) to be calculated. However, the high cost of force treadmills has limited their adoption. This paper proposes a low-cost force treadmill system with force sensors installed underneath a standard exercise treadmill. It identifies and compensates for the force transmission dynamics from the actual GRF applied on the treadmill track surface to the force transmitted to the force sensors underneath the treadmill body...
2017: Journal of Healthcare Engineering
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