66 research outputs found

    The cross on rings performed by an Olympic champion

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    The cross is a key skill in Male Artistic Gymnastics rings routines. However, few researches were found about this skill. There is knowledge about the forces needed to perform the cross, or about muscles activation, separately. The aim of this paper was to accomplish a comprehensive research about the biomechanics of cross on rings, in order to obtain a descriptive model about this skill. Therefore, the currently Olympic champion on rings event volunteered in this research. He performed three crosses with the usual apparatus in his training gym. The measurement methods were combined: One digital video camera, one strain gauge in each cable and surface electromyography of nine right shoulder muscles were used. Statistical analyses were performed by parametric and non parametric tests and descriptive statistics. Symmetry values were calculated for shoulder angles and cables of right and left side. Coefficient of variation of muscle activation and co contraction were verified. Within gymnast variability was calculated using biological coefficient of variation (BCV), discretely for kinematic measures. Low variability values of shoulder angles and cable forces were verified and low values of asymmetry as well. Muscle activation varied according to muscle function, while co-contraction values were different among trials. These results pointed out the characteristics of the cross performed by an elite gymnast. Knowledge about the characteristics of cross can inform coaches, practitioners and clinicians how a successful skill should be presented

    Asymmetry analysis of the arm segments during forward handspring on floor

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    Asymmetry in gymnastics underpins successful performance and may also have implications as an injury mechanism; therefore, understanding of this concept could be useful for coaches and clinicians. The aim of this study was to examine kinematic and external kinetic asymmetry of the arm segments during the contact phase of a fundamental skill, the forward handspring on floor. Using a repeated single subject design six female National elite gymnasts (age: 19 ± 1.5 years, mass: 58.64 ± 3.72 kg, height: 1.62 ± 0.41 m), each performed 15 forward handsprings, synchronised 3D kinematic and kinetic data were collected. Asymmetry between the lead and non-lead side arms was quantified during each trial. Significant kinetic asymmetry was observed for all gymnasts (p < 0.005) with the direction of the asymmetry being related to the lead leg. All gymnasts displayed kinetic asymmetry for ground reaction force. Kinematic asymmetry was present for more gymnasts at the shoulder than the distal joints. These findings provide useful information for coaching gymnastics skills, which may subjectively appear to be symmetrical. The observed asymmetry has both performance and injury implications

    Attractor dynamics of elite performance: the high bar longswing

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    Combining biomechanics and motor control, the aim of this study was to investigate the limit cycle dynamics during the high bar longswing across the UK elite gymnastics pathway age groupings. Senior, junior and development gymnasts (N = 30) performed three sets of eight consecutive longswings on the high bar. The centre of mass motion was examined through Poincaré plots and recurrence quantification analysis exploring the limit cycle dynamics of the longswing. Close to one-dimensional limit cycles were displayed for the senior (correlation dimension (CD) = 1.17 ± .08), junior (CD = 1.26 ± .08) and development gymnasts (CD = 1.33 ± .14). Senior elite gymnasts displayed increased recurrence characteristics in addition to longer longswing duration (p < .01) and lower radial angular velocity of the mass centre (p < .01). All groups of gymnasts had highly recurrent and predictable limit cycle characteristics. The findings of this research support the postulation that the further practice, experience and individual development associated with the senior gymnasts contribute to the refinement of the longswing from a nonlinear dynamics perspective. These findings support the idea of functional task decomposition informing the understanding of skill and influencing coaches’ decisions around skill development and physical preparation

    International Society of Biomechanics in Sport October Newsletter 2015

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    IN THIS ISSUE: Message from the President, ISBS 2015 Post Conference Report, Student Mini Research Grant Reports, ISBS Awards 2015, Call for ISBS Awards 2016, Report of Student Mentoring Program, Short Communications, ISBS Sponsors, Introducing Biomch-V, C-Motion Group Meetin

    Cellular Active N-Hydroxyurea FEN1 Inhibitors Block Substrate Entry to the Active Site

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    The structure-specific nuclease human flap endonuclease-1 (hFEN1) plays a key role in DNA replication and repair and may be of interest as an oncology target. We present the first crystal structure of inhibitor-bound hFEN1 and show a cyclic N-hydroxyurea bound in the active site coordinated to two magnesium ions. Three such compounds had similar IC50 values but differed subtly in mode of action. One had comparable affinity for protein and protein– substrate complex and prevented reaction by binding to active site catalytic metal ions, blocking the unpairing of substrate DNA necessary for reaction. Other compounds were more competitive with substrate. Cellular thermal shift data showed engagement of both inhibitor types with hFEN1 in cells with activation of the DNA damage response evident upon treatment. However, cellular EC50s were significantly higher than in vitro inhibition constants and the implications of this for exploitation of hFEN1 as a drug target are discussed
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