595 research outputs found
Functional Performance Testing in Ice Hockey: the Role of the Single Leg, Medial Countermovement Jump
Due to the physical nature of the game, injuries are common in ice hockey. Injury rates have been difficult to interpret due to the inconsistencies in the definitions of injury and athlete exposure. Consensus statements on injury definitions have been developed for sports such as soccer and rugby but have not been established in ice hockey. Furthermore, many different off-ice tests are performed, but a hockey-specific performance test has not been promoted. Accordingly, the objective for this thesis was to investigate injury rates, injury definition, athlete exposure and injury type in men’s ice hockey, and providing information on a practical test practitioners can use to monitor fatigue and measure performance. This was achieved through three research projects. An integrative literature review was conducted to suggest a specific definition of injury and athlete exposure (Chapter 2). This study identified that the International Ice Hockey Federation’s definition of injury is preferred based on the clarity and relevance of the injury description and that the preferred athlete exposure metric is player game-hours based on accuracy and ease of use. In addition, lower extremity injuries were identified as common and costly in men’s ice hockey. The single leg, medial countermovement jump was identified as an appropriate hockey-specific performance test. This jump enables objective measures of frontal plane force and power and is particularly applicable for ice hockey players given that ice skating involves applying lateral forces. All twelve parameters of the jump showed moderate to excellent reliability (Chapters 3) suggesting that this jump is a reliable test for assessing frontal plane force and power in ice hockey players. Finally, normative values and asymmetry indices were presented in ninety-one male youth hockey players aged 10–18 years (Chapter 4). In conclusion, lower extremity injuries are common in hockey and injury rates are difficult to interpret as the definition is not consistent. The single leg, medial countermovement jump is an appropriate functional test for measuring skating performance. Ice hockey performance staff can use this evidence-based research to measure performance, monitor fatigue, and document recovery from injury
A software system for pathological voice acoustic analysis
International audienceA software system for pathological voice analysis using only the resources of a personal computer with a sound card is proposed. The system is written on the basis of specific methods and algorithms for pathological voice analysis and allows evaluation of: 1) Pitch period (To); 2) Degree of unvoiceness; 3) Pitch perturbation and amplitude perturbation quotients; 4) Dissimilarity of surfaces of the pitch pulses; 5) Ratio aperiodic/periodic components in cepstra; 6) Ratio {energy in the cepstral pitch pulse}-to-{total cepstral energy}; 7) Harmonics-to-noise ratio; 8) Degree of hoarseness; 9) Ratio low-to-high frequency energies; 10) Glottal Closing Quotient. The voices of 400 persons were analyzed - 100 (50 females/50 males) normal speakers and 300 (100 females/200 males) patients. The statistical analysis shows very significant changes in PPQ, DH, DPP, DUV, APR, HNR and PECM, and significant changes in APQ and CQ
Measurement of the - mixing angle in and beams with GAMS- Setup
The results of mixing angle measurement for , mesons generated
in charge exchange reactions with and beams are preseneted.
When the , mesons are described in nonstrange(NS)--strange(S)
quark basis the and beams allow to study and
parts of the meson wave function. The cross section ratio at
(GeV/c) in the beam is , results in mixing angle . For
beam the ratio is . It was found that
gluonium content in is . The
experiment was carried out with GAMS-4 Setup.Comment: 6 pages, 4 figures, 1 table, to be submitted in European physical
journal C. Minor changes, the Bibliography extende
On the problem of interactions in quantum theory
The structure of representations describing systems of free particles in the
theory with the invariance group SO(1,4) is investigated. The property of the
particles to be free means as usual that the representation describing a
many-particle system is the tensor product of the corresponding single-particle
representations (i.e. no interaction is introduced). It is shown that the mass
operator contains only continuous spectrum in the interval
and such representations are unitarily equivalent to ones describing
interactions (gravitational, electromagnetic etc.). This means that there are
no bound states in the theory and the Hilbert space of the many-particle system
contains a subspace of states with the following property: the action of free
representation operators on these states is manifested in the form of different
interactions. Possible consequences of the results are discussed.Comment: 35 pages, Late
Study of the system in the mass range up to 1200 MeV
The reaction has been studied with GAMS-2000
spectrometer in the secondary 38 GeV/c -beam of the IHEP U-70
accelerator. Partial wave analysis of the reaction has been performed in the
mass range up to 1200 MeV. The -meson is seen as a sharp
peak in S-wave. The -dependence of production cross section has
been studied. Dominant production of the at a small transfer
momentum confirms the hypothesis of Achasov and Shestakov about significant
contribution of the exchange () in the mechanism
of meson production in -channel of the reaction.Comment: 4 pages, 3 figures, talk given at HADRON'9
On detection of narrow angle e+e- pairs from dark photon decays
A class of models of dark sectors consider new very weak interaction between
the ordinary and dark matter transmitted by U'(1) gauge bosons A' (dark
photons) mixing with our photons. If such A's exist, they could be searched for
in a light-shining-through-a-wall experiment with a high energy electron beam
from the CERN SPS. The proposed search scheme suggests detection of the e+e-
pairs produced in the A' -> e+e- decay with a very small opening angle.
Coordinate chambers based on the thin-wall drift tubes with a minimal material
budget and a two-hit resolution for e+ and e- tracks separated by more than 0.5
mm are considered as an option for detecting such pairs
Measurement of the decay form factors in the OKA experiment
A precise measurement of the vector and axial-vector form factors difference
in the decay is presented.
About 95K events of are selected in
the OKA experiment. The result is .
Both errors are smaller than in the previous measurements.Comment: 9 pages, 8 figure
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