BALL IMPACT KINEMATICS AND DYNAMICS IN SOCCER KICKING

The purpose of this study was to illustrate dynamic behaviours of shank, foot and ball through ball impact phase. A time-frequency filtering approach succeeded in establishing more representative shank kinematics just before, during and just after ball impact whereas other procedures failed to remove noisy oscillation from the baseline, lost the peaks of rapid changes or produced totally distorted movement patterns frequently seen in many previous studies. Likewise, ultrahigh-speed video cameras (5000 Hz) and a mathematical model of ball deformation clearly demonstrated the dynamic interaction between the foot and ball during ball impact. It can be assumed that effectual duration to accelerate the ball corresponds to approximately three fourths of visually determined ball contact time and a longer contact time did not associated with a higher ball velocity

FOOT MOVEMENT IN IMPACT PHASE OF INSTEP KICKING IN SOCCER

Ball impact technique is essential to produce a higher ball velocity in soccer instep kicking. However, to date only a few studies focused on foot kinematics during ball impact, in which plantar flexion motion of the foot was solely reported (Asai et al., 1995; Nunome et al., 2006). In this study, three-dimensional movement of the foot (plantar flexion / dorsal flexion, abduction / adduction, eversion / inversion) during ball impact was quantified to extract some movement characteristics releted to a higher ball velocity

EVALUATION OF ARM STROKE TECHNIQUE IN FRONT CRAWL SWIMMING

The purpose of the present study was to evaluate the high elbow technique in arm stroke motion, and to investigate the relationship between the technique and the swimming performance in front crawl swimming. Subjects were fourteen skilled male swimmers and five unskilled male swimmers. The arm stroke motions of subjects were captured threedimensionally (3-D) at 60 Hz during 25 m front crawl swimming. A new index of the high elbow arm stroke technique (high elbow index) was developed. The index was defined by the 3-D coordinates of the three joints (shoulder, elbow and wrist). As the result, the arm stroke technique of the skilled swimmers was different compared with the unskilled swimmers. Moreover, a significant correlation was obtained between the index and the swimming velocity. The results indicated that the index was effective to evaluate the arm stroke technique and the high elbow technique was effective for improvement of the swimming performance in front crawl swimming

Generation of a bile salt export pump deficiency model using patient-specific induced pluripotent stem cell-derived hepatocyte-like cells

Bile salt export pump (BSEP) plays an important role in hepatic secretion of bile acids and its deficiency results in severe cholestasis and liver failure. Mutation of the ABCB11 gene encoding BSEP induces BSEP deficiency and progressive familial intrahepatic cholestasis type 2 (PFIC2). Because liver transplantation remains standard treatment for PFIC2, the development of a novel therapeutic option is desired. However, a well reproducible model, which is essential for the new drug development for PFIC2, has not been established. Therefore, we attempted to establish a PFIC2 model by using iPSC technology. Human iPSCs were generated from patients with BSEP-deficiency (BD-iPSC), and were differentiated into hepatocyte-like cells (HLCs). In the BD-iPSC derived HLCs (BD-HLCs), BSEP was not expressed on the cell surface and the biliary excretion capacity was significantly impaired. We also identified a novel mutation in the 5′-untranslated region of the ABCB11 gene that led to aberrant RNA splicing in BD-HLCs. Furthermore, to evaluate the drug efficacy, BD-HLCs were treated with 4-phenylbutyrate (4PBA). The membrane BSEP expression level and the biliary excretion capacity in BD-HLCs were rescued by 4PBA treatment. In summary, we succeeded in establishing a PFIC2 model, which may be useful for its pathophysiological analysis and drug development

DECIGO pathfinder

DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) which is a future space gravitational wave antenna. DECIGO is expected to provide us fruitful insights into the universe, in particular about dark energy, a formation mechanism of supermassive black holes, and the inflation of the universe. Since DECIGO will be an extremely large mission which will formed by three drag-free spacecraft with 1000m separation, it is significant to gain the technical feasibility of DECIGO before its planned launch in 2024. Thus, we are planning to launch two milestone missions: DPF and pre-DECIGO. The conceptual design and current status of the first milestone mission, DPF, are reviewed in this article

KINETIC ANALYSIS OF THE SUPPORT LEG IN SOCCER INSTEP KICKING

The purpose of the present study was to illustrate the kinetic aspect of the support leg during soccer instep kicking. The motion was captured together with the ground reaction force using a motion capture system. Moments and angular velocities of ankle, knee and hip joint for the support leg were calculated. The ankle joint was passively rotated threedimensionally, during which these motions were counteracted to the joint moments. The knee joint motion, likewise, counteracted to the joint moment from the instant of the touch-down to just before ball impact. It is likely that the ankle and knee joints have a role in attenuating the impact of landing. In contrast, positive power due to the knee and hip extension moments appeared just before ball impact. It can be assumed that those motions may serve to lift the body thereby indirectly contributing the kick leg swing

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Results of the search for inspiraling compact star binaries from TAMA300's observation in 2000-2004

We analyze the data of TAMA300 detector to search for gravitational waves from inspiraling compact star binaries with masses of the component stars in the range 1-3Msolar. In this analysis, 2705 hours of data, taken during the years 2000-2004, are used for the event search. We combine the results of different observation runs, and obtained a single upper limit on the rate of the coalescence of compact binaries in our Galaxy of 20 per year at a 90% confidence level. In this upper limit, the effect of various systematic errors such like the uncertainty of the background estimation and the calibration of the detector's sensitivity are included.Comment: 8 pages, 4 Postscript figures, uses revtex4.sty The author list was correcte

COMPARISON OF BALL IMPACT CHARACTERISTICS BETWEEN SIDE-FOOT AND INSTEP KICKING IN SOCCER

The purpose of this study was to describe the kinematic characteristics during ball impact of soccer side-foot kicking. The foot and ball motions during ball impact phase of the instep and side-foot kicking were captured for two professional footballers using two ultra-high-speed cameras at 2000Hz. In the instep kicking, the foot was forced into plantar flexion, abduction and eversion by ball contact. On the other hand, in the sidefoot kicking, the passive plantar flexion motion was drastically restricted compared to that of instep kicking. Although the foot and ball velocity of the side-foot kicking were lower than those of the instep kicking, the efficiency of ball impact of the side-foot kicking approximately corresponded with that of the instep kicking. The complicated ball impact characteristics of side-foot kicking in highly skilled footballers were illustrated by ultrahigh- speed images