049) (ES �� 0.97). Figure 2 Example of raw Regorafenib structure EMG of rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) after different acute stretching methods (pre-static, post-static, pre-dynamic, and post-dynamic) during soccer instep kicking Figure 3 Mean �� SD changes in rectus femoris, vastus lateralis, and vastus medialis root mean square EMG during soccer instep kicking before and after static and dynamic stretching. Significant at p < 0.015, Significant at p < 0.004, Significant ... Table 2 Mean (�� SD) muscles activity, knee and ankle joints angular velocity, and foot and ball velocity descriptors of the soccer instep kicking after different acute stretching methods KAV showed a significant increase by 9.65% �� 4.92% after dynamic stretching (p = 0.002) versus a non-significant change (?1.

45% �� 4.84%) after static stretching (ES �� 0.98). Dynamic stretching (10.12% �� 5.32%) also showed greater AAV than static stretching (?3.29% �� 3.68%) (p = 0.011) (ES �� 0.96). In addition, dynamic stretching (10.77% �� 7.12%) caused significantly faster BV when compared to static stretching (?6.56% �� 3.67%) (p = 0.001) (ES �� 0.99). Discussion The main finding of this study is that, compared to static stretching, dynamic stretching of the quadriceps resulted in a higher increase of (1) VM, VL and RF muscle activation, (2) maximum knee and ankle angular velocity and (3) maximum ball velocity during an instep soccer kick. Further, dynamic stretching caused a higher increase of RF muscle activity as opposed to VM and VL muscles. The present results support previous research studies (Cramer et al.

, 2005; Marek et al., 2005) indicating that dynamic stretching increases activation of all superficial quadriceps muscles more than static stretching (Figure 3). However, in contrast to previous research studies, our results refer to a multiarticular movement, such as the soccer kick and therefore, direct comparison between the aforementioned studies is difficult. Particularly, backward and forward swinging motion of the kicking leg is mainly accompanied by a fast stretch-shortening cycle of the quadriceps (Bober et al., 1987). Along with the motion-dependent moments, the knee extensors provide the main force in order to accelerate the shank during the forward motion of the kicking leg (Kellis et al., 2006; Dorge et al., 1999).

A higher quadriceps activation and strength, coupled with a more efficient stretch-shortening cycle probably lead to a higher Dacomitinib maximal KAV (Kellis and Katis, 2007; Kellis et al., 2006) which is transmitted to the ankle and finally to the toe and increases ball speed (Asami and Nolte, 1983). Consequently, any changes observed after stretching should be related to some or all the aforementioned factors. In the present study, quadriceps muscle EMG (Figure 3) remained unaltered while angular and ball speed kinematics decreased after static stretching.