Sprint pattern analysis of professional female soccer players on artificial and natural turf
RETOS-NUEVAS TENDENCIAS EN EDUCACION FISICA DEPORTE Y RECREACION
Authors: Ariza Viviescas, Andres; Nino Pinzon, Diana Mareela; Dutra de Souza, Hugo Celso; Esteban Moreno, Juan Daniel; Benitez Medina, Diego; Sanchez Delgado, Juan Carlos
Abstract
Introduction: There is few evidence that details the behavior of each spatiotemporal variable of the running pattern of female soccer players using different surfaces. Objective: To describe the spatiotemporal variables of the sprint pattern developed on natural and artificial turf by professional female soccer players. Methods: A cross-sectional study was conducted on nineteen (n=19) professional athletes with an average age of 22.3 years, who's sprint spatiotemporal variables were evaluated in a natural (Berniuda 419) and artificial (Star 2) playing field through an optical measurement system (Opto Gait, Italy). The analysis of the differences of the space and time variables by turf was done with the Wilcoxon test for paired data and the differences in speed and acceleration by playing position was done using the Kruskal-Wallis test. The Spearman test was used to compare the correlation between speed, acceleration and anthropometric variables. Finally, an alpha level of 5% was considered for the whole analysis. Results: On the natural turf, the speed and cadence of the players were higher, on the artificial turf, the energy, flight time, contact phase and step angle were higher (p<0.05). On the other hand, an indirect relationship was observed between speed, contact time, percentage and fat weight (p=0.01). Conclusion: Our results suggest that the natural turf, Bennuda 419, allows for a faster sprinting patterns, characterized by lower energy use, flight time, contact phase and step angle.
Using a Combination of Electrochemical and Photoelectron Transfer Reactions to Gain New Insights into Oxidative Cyclization Reactions
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
Authors: Graaf, Matthew D.; Gonzalez, Luisalberto; Medcalf, Zach; Moeller, Kevin D.
Abstract
Radical cation initiated cyclization reactions can be triggered by the one electron oxidation of an electron-rich olefin using either electrochemistry or visible light and a photoredox catalyst. In principle, the two methods can be used to give complimentary products with the electrolysis leading to products derived from a net two electron oxidation and the photoelectron transfer method being compatible with the formation of products from a redox neutral process. However, we are finding an increasing number of oxidative cyclization reactions that require the rapid removal of a second electron in order to form high yields of the desired product. In those cases, the electrochemical method can provide a superior approach to accessing the necessary two electron oxidation pathway. With that said, it is a combination of the two methods that provides the mechanistic insight needed to understand when a reaction has this requirement, and we are finding that the use of photoredox catalysis in combination with electrochemical methods is changing our understanding of even the most successful anodic cyclization reactions run to date.
COA
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