Torque-angle-velocity relationships and muscle performance of professional and youth soccer players

Soccer matches consist of a variety of different activities, including repeated sprints. Time to attain velocity (TTAV), load range (LR) and the torque-angle-velocity relationship (TAV3D) represent an important measurement of muscle performance however there are few studies related. The aim of this study was to compare these outcomes between soccer players of different age category. Seventeen professional (PRO) and seventeen under-17 (U17) soccer players were assessed for concentric knee flexion/extension at 60, 120 and 300 °/s. For the extensor muscles, differences were found in favor of the U17 group for TTAV and LR outcomes at 120 °/s, however, the PRO group maintained higher torques in both movement directions in comparison to the U17 in TAV3D evaluation. These results suggest that muscle performance of the PRO group is more efficient than the U17 group

Synthesis, Characterization And Catalytic Potential Of Mgnio2 Nanoparticles Obtained From A Novel [mgni(opba)]n·9nh2o Chain

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)We describe herein the synthesis of MgNiO2 nanoparticles employing a new one-dimensional system [MgNi(opba)]n·9nH2O, with opba standing for ortho-phenylenebis(oxamato), as precursor. The MgNiO2 nanoparticles could be obtained after heat-treatment at 800 °C for 5 h under air atmosphere, which was responsible for the elimination of water and organic precursor material leading the formation of nanoparticles with average size of 40±9 nm. To this end, we first described the synthesis of [MgNi(opba)]n·9nH2O chain, which was obtained using a pre-synthetized Na2[Ni(opba)]·5H2O and Mg2+ (molar ratio of 1:1) in aqueous media and then this chain was calcined to produce the desired MgNiO2 nanoparticles. The obtained MgNiO2 nanoparticles showed good catalytic performance towards ethanol decomposition achieving 100% of substrate conversion and producing acetaldehyde (56.8%) and hydrogen (24.8%) as the main gaseous products. Also, carbon based structures of great interest for technological applications, carbon nanotubes and onions were formed as valuable byproducts. Thus, we believe that our reported results may inspire the synthesis of catalysts with improved performances for applications in other gas-phase transformations. © 2016 Elsevier Ltd and Techna Group S.r.l.42121363513641CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorFAPEMIG - CEX-APQ-02159-12, FAPEMIG, Fundação de Amparo à Pesquisa do Estado de Minas GeraisCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES