1,175 research outputs found

    AN EXAMINATION OF RETURN TO PLAY CRITERIA FOR KNEE STRENGTH 1Nl EXPERIENCED SOCCER PLAYERS

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    Clinicians often use isokinetic strength exercises in the rehabilitation of lower extremity injuries. Isokinetic testing scores are often used as criterion to determine the progression within a rehabilitation protocol as well as the suitability of the patient to return to sport participation. For example, Shelbourne, Klootwyk, and De Carlo (1995) suggested that once the anterior cruciate ligament (ACL) reconstructed extremity achieves 70% of the strength of the uninjured leg, the patient is allowed to engage in sport-specific activities and begin the progression toward competitive participation. A criterion like this would be a valid standard assuming no strength differences exist between limbs. Few bilateral differences in lower extremity strength exist in most sedentary individuals or athletes participating in bilaterally symmetrical lower extremity activities. However, soccer players usually have tendencies to use one leg more than the other for dribbling, shooting and performing long kicks. As a result, soccer can be characterized as an asymmetrical lower extremity activity. If bilateral strength differences exist, then appropriate adjustments should be made for return to activity standards. This study examined whether differences existed in isokinetic knee f1exion and extension strength between the dominant and non-dominant legs in experienced soccer players

    EFFECTS OF ANKLE STABILlZATION ON PUSH-OFF MECHANICS FROM A THREE-POINT STANCE IN FOOTBALL

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    The purpose of this investigation was to examine the effects of taping and bracing on push-off mechanics from a three-point football stance. Nineteen males were tested under three ankle stabilization conditions: braced, taped, and control. Participants performed five trials in each condition. Two 250Hz video cameras and a forceplate were used to collect data. A MANOVA with repeated measures revealed a significant main effect for condition. Post hoc analysis indicated that bracing and taping resulted in reduced minimum and maximum ankle angles and maximum angular velocity compared to the control. The horizontal velocity of the center of mass at takeofffor the tape condition was significantly lower than the control. Bracing and taping can have a negative effect on push-off mechanics

    Thermal expansion and magnetostriction of pure and doped RAgSb2 (R = Y, Sm, La) single crystals

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    Data on temperature-dependent, anisotropic thermal expansion in pure and doped RAgSb2 (R = Y, Sm, La) single crystals are presented. Using the Ehrenfest relation and heat capacity measurements, uniaxial pressure derivatives for long range magnetic ordering and charge density wave transition temperatures are evaluated and compared with the results of the direct measurements under hydrostatic pressure. In-plane and c-axis pressure have opposite effect on the phase transitions in these materials, with in-plane effects being significantly weaker. Quantum oscillations in magnetostriction were observed for the three pure compounds, with the possible detection of new frequencies in SmAgSb2 and LaAgSb2. The uniaxial (along the c-axis) pressure derivatives of the dominant extreme orbits (beta) were evaluated for YAgSb2 and LaAgSb2

    Momentum dependence of the superconducting gap in NdFeAsO1-xFx single crystals measured by angle resolved photoemission spectroscopy

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    We use angle resolved photoemission spectroscopy (ARPES) to study the momentum dependence of the superconducting gap in NdFeAsO1-xFx single crystals. We find that the Gamma hole pocket is fully gapped below the superconducting transition temperature. The value of the superconducting gap is 15 +- 1.5 meV and its anisotropy around the hole pocket is smaller than 20% of this value. This is consistent with an isotropic or anisotropic s-wave symmetry of the order parameter or exotic d-wave symmetry with nodes located off the Fermi surface sheets. This is a significant departure from the situation in the cuprates, pointing to possibility that the superconductivity in the iron arsenic based system arises from a different mechanism.Comment: 4 pages, 3 figure

    Flexible provisioning of Web service workflows

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    Web services promise to revolutionise the way computational resources and business processes are offered and invoked in open, distributed systems, such as the Internet. These services are described using machine-readable meta-data, which enables consumer applications to automatically discover and provision suitable services for their workflows at run-time. However, current approaches have typically assumed service descriptions are accurate and deterministic, and so have neglected to account for the fact that services in these open systems are inherently unreliable and uncertain. Specifically, network failures, software bugs and competition for services may regularly lead to execution delays or even service failures. To address this problem, the process of provisioning services needs to be performed in a more flexible manner than has so far been considered, in order to proactively deal with failures and to recover workflows that have partially failed. To this end, we devise and present a heuristic strategy that varies the provisioning of services according to their predicted performance. Using simulation, we then benchmark our algorithm and show that it leads to a 700% improvement in average utility, while successfully completing up to eight times as many workflows as approaches that do not consider service failures

    Restrictions Limiting the Generation of DNA Double Strand Breaks during Chromosomal V(D)J Recombination

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    Antigen receptor loci are composed of numerous variable (V), diversity (D), and joining (J) gene segments, each flanked by recombination signal sequences (RSSs). The V(D)J recombination reaction proceeds through RSS recognition and DNA cleavage steps making it possible for multiple DNA double strand breaks (DSBs) to be introduced at a single locus. Here we use ligation-mediated PCR to analyze DNA cleavage intermediates in thymocytes from mice with targeted RSS mutations at the endogenous TCRβ locus. We show that DNA cleavage does not occur at individual RSSs but rather must be coordinated between RSS pairs flanking gene segments that ultimately form coding joins. Coordination of the DNA cleavage step occurs over great distances in the chromosome and favors intra- over interchromosomal recombination. Furthermore, through several restrictions imposed on the generation of both nonpaired and paired DNA DSBs, this requirement promotes antigen receptor gene integrity and genomic stability in developing lymphocytes undergoing V(D)J recombination
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