GAZE AND STEP CONTROLS OF AN ELITE ATHLETE DURING APPROACHING DIFFERENT HURDLE HEIGHTS

This study investigated the gaze and step controls of one elite male hurdler when approaching hurdles at different heights. Across a 16 m runway, the participant performed three normal sprinting trials, and three hurdle running trials to clear a low, medium and high hurdle respectively. Gaze behaviour was captured using a mobile eye tracker that was mounted on the participant’s head and was filtered using a low-pass filter. In normal sprinting, the step length increased gradually from the first to eighth step. In the hurdle running trials, step length did not increase in the last step and fixations remained on the hurdle. The duration of fixations on the hurdle was lengthened by 21% and 44% in the middle and high hurdle trials, respectively, compared with the low hurdle trials. This pilot study provides foundational information on the interaction between gaze and hurdle running to clear hurdles of different heights that could potentially be optimized to improve performance in hurdling

THE EFFECT OF VISUAL GAZE LOCATION ON BLOCK-START BIOMECHANICS IN ATHLETICS

This study investigated the effects of varying visual gaze location (VGL), by means of externally-focused instruction, during the block-start “set” phase with the intention of optimizing block-start biomechanics for faster starts in an athlete-specific manner. Nine collegiate sprinters performed a series of block-starts while directing their VGL to their personal baselines, and at 0.5m, 1m, 2m and 3m from the start line. Twelve infrared opto-reflective cameras and one force plate were utilized to assess trunk, hip, knee and centre of mass kinematics, and blocks push-phase kinetics. An eyetracker was used to determine participants’ VGL. Some postural changes observed were a significant decrease in pelvic height in the “set” position, and more upright trunk postures at toe-off from the blocks, when participants gazed further at 2m and 3m. Gazing at 1m was effective in eliciting changes to pelvic horizontal velocity. These results suggest that manipulating VGL could help certain athletes to optimize their block-start biomechanics for faster starts. Coaches can consider redirecting VGL in addition to usual instructional methods to improve the block-start performances of athletes

THE DIFFERENCES IN THREE-DIMENSIONAL KINETICS IN LOWER LIMB JOINTS OF SPRINTERS AND NOVICE RUNNERS DURING A START DASH

The purpose of this study was to clarify the differences in the three-dimensional joint moments of lower limbs between sprinters and novice runners. A total of 12 male sprinters and 11 healthy male college students participated in a start-dash experiment. At pushing the front starting block, in hip joint, extension moment of sprinters was significantly greater than that of novices. On the other hands, in ankle joint, not only the plantarflexion moments but also the inversion moment of sprinters was significantly greater than those of novices. Moreover, the peak value of the plantarflexion moment was positively correlated with that of the inversion moment. These results suggest that the greater ankle flexion-extension moment is achieved by coordinating with the greater inversion moments when attempting to increase acceleration ability

Molecular cloning of a cDNA encoding human ribosomal protein L39

A cDNA clone encoding a human ribosomal protein L39 (hRPL39) was isolated through a random cDNA sequencing approach to a cDNA library constructed from a human colon carcinoma cell line of COLO 205. Although levels of hRPL39 mRNA were different in several cell lines including carcinoma cell lines from different tissues, they were shown not to be cell cycle-dependent in a human fibroblast cell line of TIG-1

COMPARISON OF GOLF SWING PATTERNS IN SKILLED FEMALE GOLFERS AMONG THREE DIFFERENT CLUBS

The purpose of this study was to compare golf swing patterns using three different clubs among skilled golfers. Five right-handed female professional golfers used their own three clubs (driver, 5-iron, and 9-iron) to hit standard golf balls in our laboratory. 3D coordinates of body and club landmarks during the swing motions were recorded using a 3D motion capture system with operating at 250 Hz frame rates. As the results, the acceleration of club head in each club during downswing reached a maximum around about 0.08 s before impact during similar swing time, and the height of club head at the maximum acceleration showed about 55% of ratio for the body height despite differences of clubs. Skilled golfers therefore might feel as the similar patterns of golf swing even if they are swinging with different length clubs

THE ENERGY CONVERSION EFFICIENCY OF DRIVER SHOT IN FEMALE PROFESSIONAL AND AMATEUR GOLFERS

The purpose of this study was to evaluate the performance of driver shot from the viewpoint of the energy conversion efficiency between club head and ball at impact. Six female professional golfers and six female amateur golfers participated in this study. All subjects were instructed to hit a straight ball with their usual swing. Each subject performed ten trials. Three dimensional coordinates of reflective markers attached on a body and club landmarks were obtained using the motion capture system operating at 250 Hz. High speed camera was used to measure the movement of the club head and ball. The energy conversion efficiency was significantly different between professional and amateur golfers (

ASSESSMENT OF ANALYZING BLOCK START PERFORMANCE WITHOUT ARM GROUND REACTION FORCES

The purpose of this study was to assess the analysing reaction time (RT) and normalized power when calculated using two different methods: a method using ground reaction forces (GRFs) of only the legs (legs F-based method) and a method using GRFs of arms and legs (whole F-based method). In total, 127 block start motions from fourteen male sprinters were analysed from all participants. The RT of the legs F-based method was not similar to that of the whole F-based method: the mean difference was 7.4 ms and the 95% CI was –45.1–59.8 ms. In contrast, the normalized power of the legs F-based method was similar to that of the whole F-based method. This information will help reconsider the golden standard methods currently used to analyse RT and encourage the use of analysis methods to analyse the performance in block starts

Transforming growth factor α protects against Fas-mediated liver apoptosis in mice

AbstractThe Fas/Fas ligand interaction plays a crucial role in various liver diseases, and administration of agonistic anti-Fas antibody to mice causes massive hepatic apoptosis and fulminant hepatic failure. Several growth factors have recently been found to function in preventing apoptosis. In this study, we demonstrated that overexpression of transforming growth factor α (TGFα) has a dramatic protective effect on Fas-mediated hepatic apoptosis at the biochemical and histological levels. Moreover, 85.7% (six out of seven) of TGFα transgenic mice survived the lethal liver damage, whereas all wild-type mice died. Expression of Bcl-xL, an anti-apoptotic protein, was greatly increased in the transgenic mice. Taken together, our findings suggest that TGFα protects against Fas-mediated liver apoptosis in vivo and up-regulation of Bcl-xL may participate in protective effect of TGFα

Overexpression of hepatocyte growth factor/scatter factor promotes vascularization and granulation tissue formation in vivo

AbstractThe effect of hepatocyte growth factor/scatter factor (HGF/SF) during wound healing in the skin was investigated, using HGF/SF-overexpressing transgenic mouse model. Histological analysis of HGF/SF transgenic mouse excisional wound sites revealed increased granulation tissue with marked vascularization. Northern blot analysis demonstrated that, relative to control, vascular endothelial growth factor (VEGF) expression in transgenic skin was significantly higher at baseline and was robustly up-regulated during wound healing. Elevated levels of VEGF protein were detected immunohistochemically, predominantly in endothelial cells and fibroblasts within the granulation tissue of HGF/SF transgenic skin. Serum levels of VEGF were also elevated in HGF/SF transgenic mice. Thus, results from our study suggest that HGF/SF has a significant effect on vascularization and granulation tissue formation during wound healing in vivo, involving with induction of VEGF

Prevention of lethal hepatic injury in Long-Evans Cinnamon (LEC) rats by D-galactosamine hydrochloride

Repeated injections of D-galactosamine hydrochloride (GalN) increase the survival rate of Long-Evans Cinnamon (LEC) rats, an animal model of Wilson’s disease. The aim of the present study was to investigate the mechanism of GalN for prevention of spontaneous lethal hepatic injury in LEC rats. MaleLEC rats were given a single subcutaneous injection of 300mg/kg of GalN or vehicle (0.9%NaCl) at 14weeks, and killed at 28 weeks of age. Next, 6-week-old male LEC rats were given weekly subcutaneous injections of 300 mg/kg of GalN or vehicle for 3 or 12 weeks, and their hepatic 8-hydroxydeoxy-2’-guanosine (8-OHdG), glutathione peroxidase (GPX), and catalase activities were measured. None of GalN-treated rats died of hepatic injury (0/12), whereas the mortality rate of control rats given 0.9% NaCl was 17% (2/12). GalN administration for 12 weeks decreased the hepatic 8-OHdG, and GalN administration for either 3 or 12weeks increased the glutathione peroxidase activity. GalN administration increased the serum level of alanine aminotransferase, and accelerated megalocytic degeneration of the hepatocytes. GalN treatment is effective in preventing lethal hepatitis in LEC rats and decrease of oxidative DNA damage by GalN plays an important role in increase of the survival rate