Kinematic and electromyographic analysis of the overhead squat in individuals showing excessive medial knee displacement

Dynamic knee valgus is a multi-planar motion that has been associated with anterior cruciate ligament injuries and patellofemoral pain syndrome. Clinical assessment of dynamic knee valgus can be made by looking for the visual appearance of excessive medial knee displacement (MKD) in the double-leg squat (DLS). The purpose of this dissertation was to identify the movement patterns and neuromuscular strategies associated with MKD during the DLS. Twenty-four control subjects and eight individuals showing MKD during the DLS participated in the study. Significant differences were verified between subjects that demonstrated MKD and a control (CON) group for the eletromyographic amplitude of adductor magnus, biceps femoris, vastus lateralis and vastus medialis muscles (p < 0.05), during the descending phase of the DLS. During the ascending phase were found group differences for adductor magnus and rectus femoris muscles (p < 0.05). Results from kinematic analysis revealed higher minimum and maximum values of ankle abduction and knee internal rotation angles (p < 0.05) for the MKD group. Also, individuals showing excessive MKD had higher hip adduction/abduction excursion. Our results suggested that higher tibial internal rotation and knee internal rotation angles in the initial position of the DLS are associated with MKD. The neuromuscular strategies that contributed to MKD were higher adductor magnus activation, whereas biceps femoris, vastus lateralis and vastus medialis activated more to stabilize the knee in response to the internal rotation moment.

The export performance of the 2004 EU enlargement economies since the 1990s : a constant market share analysis

This study focuses the export performance of the 2004 EU enlargement economies between 1990 and 2013. The long time span analysed allows to capture different stages in the relationship of these new members with the EU before and after accession. The study is based on the Constant Market Share methodology of decomposing an ex-post country’s export performance into different effects. Two different Constant Market Share Analysis (CMSA) were selected in order to disentangle, for the exports of the new members to the EU15, (i) the growth rate of exports and (ii) the growth rate of exports relatively to the world. Both approaches are applied to manufactured products first without disaggregating results by sectors and then grouping all products into two different classification of sectors: one considering the technological intensity of manufactured exports and another evaluating the specialization factors of the products exported. Results provide information not only on the ten economies’ export performance as a group but also individually considered and on the importance of each EU15 destination market to the export performance of these countries.