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Percorrer por autor "Seifert, Ludovic"

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  • Cluster stability as a new method to assess changes in performance and its determinant factors over a season in young swimmers
    Publication . Morais, J.E.; Silva, A.J.; Marinho, D.A.; Seifert, Ludovic; Barbosa, Tiago M.
    To apply a new method to identify, classify, and follow up young swimmers based on their performance and its determinant factors over a season and analyze the swimmers' stability over a competitive season with that method. Methods: Fifteen boys and 18 girls (11.8 +/- 0.7 y) part of a national talent-identification scheme were evaluated at 3 different moments of a competitive season. Performance (ie, official 100-m freestyle race time), arm span, chest perimeter, stroke length, swimming velocity, speed fluctuation, coefficient of active drag, propelling efficiency, and stroke index were selected as variables. Hierarchical and k-means cluster analysis were computed. Results: Data suggested a 3-cluster solution, splitting the swimmers according to their performance in all 3 moments. Cluster 1 was related to better performances (talented swimmers), cluster 2 to poor performances (nonproficient swimmers), and cluster 3 to average performance (proficient swimmers) in all moments. Stepwise discriminant analysis revealed that 100%, 94%, and 85% of original groups were correctly classified for the 1st, 2nd, and 3rd evaluation moments, respectively (0.11 <= A <= 0.80; 5.64 <= chi(2) <= 63.40; 0.001 < P <= .68). Membership of clusters was moderately stable over the season (stability range 46.1-75% for the 2 clusters with most subjects). Conclusion.- Cluster stability is a feasible, comprehensive, and informative method to gain insight into changes in performance and its determinant factors in young swimmers. Talented swimmers were characterized by anthropometrics and kinematic features
    2015Artigo científico Acesso aberto Ver mais
  • Fractal analysis of human aquatic locomotion: an exploratory and descriptive study
    Publication . Barbosa, Tiago M.; Morais, J.E.; Costa, M.J.; Seifert, Ludovic; Pendergast, David
    Fractal analysis has recently been applied to study a wide range of objects/systems in Biology and Medicine to assess non-linear phenomena. Human swimming is a non-linear behavior and as much as we are aware, no fractal research was conducted in such locomotion technique.
    2014Póster em conferência Acesso aberto Ver mais