137 research outputs found

    The effect of contact sport expertise on postural control

    Get PDF
    It has been demonstrated that expertise in sport influences standing balance ability. However, little is known concerning how physical contact in sport affects balance ability. The aim of this study was to examine whether differences between contact and limited-contact sport experiences results in differences in postural control. Twenty male collegiate athletes (10 soccer/contact, 10 baseball/limited contact) and ten male untrained students stood quietly on a force plate under various bipedal and unipedal conditions, with and without vision. Significant differences for sway area and COP speed were found between the soccer players and the other two groups for unipedal stances without vision. Soccer players were found to have superior postural control compared with participants involved in limited contact sport or no sport at all. Contact sports may lead to increased postural control through enhanced use of proprioceptive and vestibular information

    The effect of uphill and downhill slopes on weight transfer, alignment and shot outcome in golf

    Get PDF
    The aim of the study was to examine changes in weight transfer, alignment and shot outcome during golf shots from flat, uphill, and downhill slopes. Twelve elite male golfers hit 30 shots with a six-iron from a computer assisted rehabilitation environment (CAREN) used to create 5° slopes while collecting 3D kinematics and kinetics of the swing. A launch monitor measured performance outcomes. A shift in the centre of pressure was found throughout the swing when performed on a slope, with the mean position moving approximately 9% closer to the lower foot. The golfers attempted to remain perpendicular to the slope, resulting in the weight transfer towards the lower foot. The golfers adopted a wider stance in the sloped conditions and moved the ball towards the higher foot at address. Ball speed was not significantly affected by the slope, but launch angle and ball spin were. As predicted by the coaching literature, golfers were more likely to hit shots to the left from an uphill slope and to the right for a downhill slope. No consistent compensatory adjustments in alignment at address or azimuth were found, with the change in final shot dispersion due to the lateral spin of the ball

    The effect of uphill and downhill slopes on centre of pressure movement, alignment and shot outcome in mid-handicap golfers

    No full text
    The aim of the study was to examine changes in centre of pressure (COP) movement, alignment and shot outcome during golf shots from flat, uphill, and downhill slopes by midhandicap golfers. Twelve male golfers hit balls with a six-iron from the flat and 5° slopes while kinematics and kinetics of the swing were collected. A launch monitor measured performance outcomes. A shift in the centre of pressure was found during the backswing when playing on a slope, but disappeared during the downswing. Golfers attempted to align the body perpendicular to the slope at the start of the swing resulting in COP movement towards the lower foot, but were not able to maintain this throughout the swing, like low handicap golfers. There was no significant difference in stance width, but golfers placed the ball closer to the uphill foot on a slope. Ball speed was not significantly affected by the slope, but launch angle and ball spin were. Golfers were more likely to hit shots to the left from an uphill slope and to the right for a downhill slope. No consistent compensatory adjustments in alignment at address were found, with differences in final ball position due to lateral spin

    Where in a time constrained throwing task is the speed-accuracy trade-off?

    No full text
    Previous research on fielding in cricket and baseball has focused on the technique and speed-accuracy trade-off of the throw in isolation from a typical sequence of fielding actions; approach, gather and throw. The present study aimed to determine whether a speed-accuracy trade-off existed in fielding and where within the above sequence the trade-off occurs. Participants, who were elite cricketers, were required to run to a stationary ball and throw to the centre of a target in order to run-out a virtual batter. High-speed video was used to record the time of approach, time in contact with, and time of flight of the ball. Two-way ANOVAs were used to determine differences in group (gender) and condition (instructions to prioritise speed or accuracy). A speed-accuracy trade-off was found, with both groups being quicker in the approach and spending less time in contact with the ball in the speed condition; however, the horizontal velocity of the throw remained the same in both conditions. It was proposed the drop in accuracy in the speed condition may be associated with less time spent aiming. It was found that instructions triggered a change in throwing technique for 31% of the participants, which requires further investigation

    Kaplan-Meier survival analysis for all patients with pulmonary LELC.

    No full text
    <p>Higher MLR (A, B), elevated LDH level (C, D), and advanced stage (E, F) were significantly associated with inferior OS and PFS (p<0.05).</p

    ROC curve analysis for the optimal cut-off point of MLR.

    No full text
    <p>The most discriminative cut-off value of MLR was 0.262 with an AUC value of 0.667 (p = 0.028). The sensitivity and specificity were 75.0% and 60.0%, respectively.</p

    Kaplan-Meier survival analysis for patients of pulmonary LELC who received radical surgery.

    No full text
    <p>Higher MLR was significantly associated with inferior OS (A) and PFS (B) (p<0.05).</p

    Survival curves according to treatment for all patients with pulmonary LELC.

    No full text
    <p>Patients who received radical surgery had significantly better OS (A) and PFS (B) than those who did not undergo radical surgery (both p<0.0001).</p

    Selective Proton/Deuteron Transport through Nafion|Graphene|Nafion Sandwich Structures at High Current Density

    No full text
    Ion current densities near 1 A cm<sup>–2</sup> at modest bias voltages (<200 mV) are reported for proton and deuteron transmission across single-layer graphene in polyelectrolyte-membrane (PEM)-style hydrogen pump cells. The graphene is sandwiched between two Nafion membranes and covers the entire area between two platinum–carbon electrodes, such that proton transfer is forced to occur through the graphene layer. Raman spectroscopy confirms that buried graphene layers are single-layer and relatively free of defects following the hot-press procedure used to make the sandwich structures. Area-normalized ion conductance values of approximately 29 and 2.1 S cm<sup>–2</sup> are obtained for proton and deuteron transport, respectively, through single-layer graphene, following correction for contributions to series resistance from Nafion resistance, contact resistance, etc. These ion conductance values are several hundred to several thousand times larger than in previous reports on similar phenomena. A ratio of proton to deuteron conductance of 14 to 1 is obtained, in good agreement with but slightly larger than those in prior reports on related cells. Potassium ion transfer rates were also measured and are attenuated by a factor of many thousands by graphene, whereas proton transfer is attenuated by graphene by only a small amount. Rates for hydrogen and deuterium ion exchange across graphene were analyzed using a model whereby each hexagonal graphene hollow site is assumed to transmit ions with a specific per-site ion-transfer self-exchange rate constant. Rate constant values of approximately 2500 s<sup>–1</sup> for proton transfer and 180 s<sup>–1</sup> for deuteron transfer per site through graphene are reported
    corecore