54 research outputs found

    A THREE-DIMENSIONAL ANALYSIS OF THE VOLLEYBALL ONE-FOOT JUMP SPIKE

    Get PDF
    INTRODUCTION: Since the Chinese National female volleyball team developed the one-foot jump spike technique during the 1980s, the high percentage of successful spiking has made the skill a powerful offensive weapon on volleyball courts all over the world. But no research has been done on the biomechanical analysis of the female one-foot jump spike. The purpose of this study was to describe the biomechanical characteristics of the techniques of the one-foot jump spike demonstrated by elite Taiwanese female players. METHODS: Four elite female players from the Taiwanese National Volleyball Team served as subjects. Their mean height, weight, and age (and variance) were 1.78 (0.03) m, 63.53 (.11) kg, and 21.50 (.58) years, respectively. Two Peak Performance high speed video cameras operating at 120Hz were synchronized to record the actions employed by the subjects in performing the one-foot jump spike. Three-dimensional object space co-ordinates of digitized image co-ordinates were obtained using a DLT algorithm and 19 calibration points in the video volume. RESULTS: [Table 1] The values of selected variables for the one-foot jump spike by the four female players were calculated (Table 1). The elite female one-foot jump spikers had a shorter takeoff time(0.198s) than the elite male two-foot spikers(0.308s).The female one-foot jump spikers also had a sharper approach angle(27 deg)then the elite male and female two-foot spikers(45- 60 deg) which made it harder for the opponent to block the ball. The results of this study provide valuable information for teachers and coaches teaching players to perform the one-foot jump spike. CONCLUSIONS: The results indicated that elite female one-foot jump spikers have a shorter takeoff time and a sharper approach angle then the elite male and female two-foot spikers, which contribute to the success of spiking

    THE APPLICATION OF RANGE OF MOTION (ROM) AND COORDINATION ON VOLLEYBALL SPIKE

    Get PDF
    The purpose of this study was to investigate the suitable timing and coordination of body segments during volleyball spike, and find the critical concepts applied on spikinglearning in the air. Cinematography (250 frame/sec, sagittle plane) was used in this study, and Kwon 3D software was used to analyze the timing and coordination of arm swing motion in the air among top and second level female volleyball athletes. The results of this study as following: 1. Enough range of motion (ROM) before ball hitting is the main factor of spiking technique; 2. Proper time-distribution of back-swing, turn-swing and forward-swing cause the proper time of ball hitting. The conclusion of spiking technique was described as following hint concepts: 1. “lead”: leading back swing at the beginning of takeoff, 2. “pull”: back swing by pull of elbow and wrist, simultaneously. 3. “turn”: make a enough ROM of swing phase. 4. “up”: during up, 5. “hit”:hitting ball by arm and body momentum

    KINEMATIC ANALYSIS OF TENNIS VOLLEY

    Get PDF
    The purpose of this study was to examine selected kinematic variables of the tennis volley. Fifteen skilled tennis players performed volley strokes under five (right, rightmiddle, middle, left-middle, left) different lateral contact locations. A ball machine was modified so subjects could not predict the ball trajectory before it was released from the machine. Two high-speed cameras (250Hz) were genlocked to collect the data and the Kwon3D software was used to analyze the temporal and kinematic variables. The results indicated the middle location have the shortest pushing (0.249s) and stroke (0.466s) time than other locations. An ipsilateral side step occurred more often in Backhand (BH, 86%) than in Forehand (FH, 67%). In addition, more FH volley (55%) was used than BH (45%) when return the ball from middle location

    Copper Transport Protein Antioxidant-1 Promotes Inflammatory Neovascularization via Chaperone and Transcription Factor Function

    Get PDF
    Supplementary information accompanies this paper at http://www.nature.com/srepCopper (Cu), an essential micronutrient, plays a fundamental role in inflammation and angiogenesis; however, its precise mechanism remains undefined. Here we uncover a novel role of Cu transport protein Antioxidant-1 (Atox1), which is originally appreciated as a Cu chaperone and recently discovered as a Cu-dependent transcription factor, in inflammatory neovascularization. Atox1 expression is upregulated in patients and mice with critical limb ischemia. Atox1-deficient mice show impaired limb perfusion recovery with reduced arteriogenesis, angiogenesis, and recruitment of inflammatory cells. In vivo intravital microscopy, bone marrow reconstitution, and Atox1 gene transfer in Atox1(-/-) mice show that Atox1 in endothelial cells (ECs) is essential for neovascularization and recruitment of inflammatory cells which release VEGF and TNFα. Mechanistically, Atox1-depleted ECs demonstrate that Cu chaperone function of Atox1 mediated through Cu transporter ATP7A is required for VEGF-induced angiogenesis via activation of Cu enzyme lysyl oxidase. Moreover, Atox1 functions as a Cu-dependent transcription factor for NADPH oxidase organizer p47phox, thereby increasing ROS-NFκB-VCAM-1/ICAM-1 expression and monocyte adhesion in ECs inflamed with TNFα in an ATP7A-independent manner. These findings demonstrate a novel linkage between Atox1 and NADPH oxidase involved in inflammatory neovascularization and suggest Atox1 as a potential therapeutic target for treatment of ischemic disease.SS is a British Heart Foundation (BHF) PhD student; GDA is BHF Chair in cardiac surgery and NIHR Senior Investigator; CE is a BHF Senior Research Fellow. Sources of Funding: This research was supported by NIH R01 HL070187 (T.F.), Department of Veterans Affairs Merit Review grant 1I01BX001232 (T.F.), R01HL116976 (T.F., M.U.-F.), NIH R01 HL077524 and HL077524-S1, R21HL112293 (to M.U.-F.), Ruth L. Kirschstein-National Service Research Award (Kirschstein-NRSA) T32 Training Grant (to G-F.C.), AHA Post-doctoral Fellowship 09POST2250151 (to N.U.), and 11POST5740006 (to V.S.).Peer-reviewedPublisher Versio

    An Overview of Regional Experiments on Biomass Burning Aerosols and Related Pollutants in Southeast Asia: From BASE-ASIA and the Dongsha Experiment to 7-SEAS

    Get PDF
    By modulating the Earth-atmosphere energy, hydrological and biogeochemical cycles, and affecting regional-to-global weather and climate, biomass burning is recognized as one of the major factors affecting the global carbon cycle. However, few comprehensive and wide-ranging experiments have been conducted to characterize biomass-burning pollutants in Southeast Asia (SEA) or assess their regional impact on meteorology, the hydrological cycle, the radiative budget, or climate change. Recently, BASEASIA (Biomass-burning Aerosols in South-East Asia: Smoke Impact Assessment) and the 7-SEAS (7- South-East Asian Studies) Dongsha Experiment were conducted during the spring seasons of 2006 and 2010 in northern SEA, respectively, to characterize the chemical, physical, and radiative properties of biomass-burning emissions near the source regions, and assess their effects. This paper provides an overview of results from these two campaigns and related studies collected in this special issue, entitled Observation, modeling and impact studies of biomass burning and pollution in the SE Asian Environment. This volume includes 28 papers, which provide a synopsis of the experiments, regional weatherclimate, chemical characterization of biomass-burning aerosols and related pollutants in source and sink regions, the spatial distribution of air toxics (atmospheric mercury and dioxins) in source and remote areas, a characterization of aerosol physical, optical, and radiative properties, as well as modeling and impact studies. These studies, taken together, provide the first relatively complete dataset of aerosol chemistry and physical observations conducted in the sourcesink region in the northern SEA, with particular emphasis on the marine boundary layer and lower free troposphere (LFT). The data, analysis and modeling included in these papers advance our present knowledge of source characterization of biomass-burning pollutants near the source regions as well as the physical and chemical processes along transport pathways. In addition, we raise key questions to be addressed by a coming deployment during springtime 2013 in northern SEA, named 7-SEASBASELInE (Biomass-burning Aerosols Stratocumulus Environment: Lifecycles and Interactions Experiment). This campaign will include a synergistic approach for further exploring many key atmospheric processes (e.g., complex aerosol-cloud interactions) and impacts of biomass burning on the surface-atmosphere energy budgets during the lifecycles of biomass burning emissions

    Effects of chronic cold exposure on the endothelin system

    No full text

    The Counterbalance of Skin Metabolism on Orbits and Diseases

    No full text
    Human organ functions are regulated by the nervous system. When human cells receive a message, this message is transmitted to the nervous system through a series of signal transmission processes. Skin conditions that occur after applying skin cream are closely related to signal transmission and nervous regulation. We determined the connection between signal regulation and natural rhythmic operations. The diurnal variations resulting from the earth’s rotation and indicate the relative relationships between the sympathetic nervous system and the parasympathetic nerve system. A spectrum was developed to assess neural transmission conditions by using skin signals which from Fourier transformation of the waves and established the association between the spectrum and diseases. The results could explain the relationships between the neurological illnesses and established spectrum. The objective was to promote the use of this spectrum as a new tool for conducting the nervous system tests in the future
    • …
    corecore