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EN
Sport-specific tests are rarely investigated in synchronized swimming (synchro). The aim of this research was to study the reliability and the validity of two sport-specific tests that are based on synchro elements, namely, the Barracuda thrust ("Barracuda") and the Boost. The Barracuda is a move in which the swimmer begins in the back pike position (head down with the legs perpendicular to the surface of the water) and then moves the legs and hips rapidly upward, unrolling the body to obtain a maximal vertical position above the surface of the water. The Boost occurs when the swimmer rises rapidly out of the water, head first, to bring as much of the body as possible above the surface of the water. Both patterns are considered power moves and are therefore theoretically related to explosive strength. This study involved 22 female competitive synchro swimmers aged 16-18 years. The variables examined included performance on the Barracuda, Boost and countermovement jump and anthropometric measures (body height, body weight and body composition). Statistical analyses showed appropriate reliability for all tests, with no systematic bias between trials. A factor analysis calculated for the Barracuda, Boost and countermovement jump revealed one significant factor based on the Guttmann-Kaiser criterion with all three tests significantly projected. The structure of the significant factor did not change if the results for the Boost and Barracuda were normalized for body height. The Boost and Barracuda, but not the countermovement jump, were significantly correlated with the competitive achievements of the swimmers. In conclusion, the Boost and Barracuda are reliable and valid measures of the explosive strength of synchronized swimmers and are significantly related to competitive achievement.
EN
The forward-sprint is considered to be, and is regularly performed as, a unique measure of “on-ground” linearspeed performance. Thus far, no investigation has simultaneously studied different forms of linear-speed or investigated whether different forms of linear-speed should be observed as unique performance quality. The purpose of this study was to determine (I) the achievements (i.e. execution time), and (II) the reliability and inter-relationships between various linear-speed performances. The participants were 42 male physical education students with substantial sport-specific backgrounds. We applied a total of six tests: three quadrupedal (supine backward, supine forward, and pronate backward locomotion) and three bipedal-performances (forward sprinting, backward sprinting, lateral shuffling). All of the tests showed appropriate reliability parameters (Cronbach Alpha ranged from 0.91 to 0.97; Inter-Item-R 0.78-0.92; Coefficient-of-Variation 1.3-9.1). The tests used in this study shared between 9% and 50% of the common variance. Our results suggest that different activities require activity-specific tests of linear-speed. This is particularly significant in those sports and activities in which quadrupedal locomotion patterns are highly important (wrestling, physically trained military services, law enforcement, fire and rescue, protective services).
5
75%
Open Chemistry
|
2005
|
vol. 3
|
issue 4
731-741
EN
Principal Component Analysis (PCA) was used for the mapping of geochemical data. A testing data matrix was prepared from the chemical and physical analyses of the coals altered by thermal and oxidation effects. PCA based on Singular Value Decomposition (SVD) of the standardized (centered and scaled by the standard deviation) data matrix revealed three principal components explaining 85.2% of the variance. Combining the scatter and components weights plots with knowledge of the composition of tested samples, the coal samples were divided into seven groups depending on the degree of their oxidation and thermal alteration. The PCA findings were verified by other multivariate methods. The relationships among geochemical variables were successfully confirmed by Factor Analysis (FA). The data structure was also described by the Average Group dendrogram using Euclidean distance. The found sample clusters were not defined so clearly as in the case of PCA. It can be explained by the PCA filtration of the data noise.
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