, 2002). It has been noted that players experience fatigue both towards the end of a game and temporarily over its duration (Kellis et al., 2006). Fatigue experienced during a soccer game is manifested by a reduced capacity to perform http://www.selleckchem.com/products/Cisplatin.html the critical actions of high intensity mentioned above, along with a progressive reduction of muscle strength. Thus, the ability to resist the negative effects of fatigue is a key factor for a soccer player. Fatigue can be considered as a performance constraint that affects the motor processing and perceptual processing that is linked to the performing skills required in game situations (McMorris and Graydon, 1997). The negative effect of fatigue may be due to a neuromuscular decrease in performance induced by acute and immediate effort.

This is probably caused by changes in muscle strength and coordination due to physiological causes and inherent metabolic changes (Kellis et al., 2006; Mohr et al., 2005). Some studies have found significant effects of local muscle fatigue protocols on the performance of complex discrete movements as in handball throwing (Forestier and Nougier, 1998) and vertical jumping (Rodacki et al., 2001). Others, using fatigue protocols related to long-distance running, have reported a significant decline in leg power, maximum isometric force and activity of the quadriceps (Nicol et al., 1991) as well as alterations in circuit reaction force (GRF) and joint kinematics of running (Madigan and Pidcoe, 2003; Mizrahi et al., 2000). Although fatigue is considered an important factor in soccer as well as in soccer skills proficiency (Mohr et al.

, 2005; Stone and Oliver, 2009) and despite the fact that player kicking ability is seen as one of the most important determinants of soccer performance (Rampinini et al., 2009; Russell et al., 2011), few studies have examined the effect of fatigue on ball velocity in the soccer kicking performance. Some studies have tried to explain the effect of fatigue on physical conditioning variables related to biomechanical and muscular analysis in the lower limbs based on the effects of prolonged intermittent specific soccer exercises. It was found that after fatigue an increased electro-mechanical delay and knee joint laxity occurs together with a significant decline of maximum isokinetic moment of force of both knee extensors and flexors (Drust et al., 2000; Rahnama et al.

, 2003). It was also found that fatigue developed during a match after relatively intense intermittent activities negatively affected the short-passing performance ability as shown by the increased number of errors made during the test and the time required to perform the test (Rampinini et al., 2008). With respect to the studies Dacomitinib considering the soccer kicking performance most of them occur in conditions with no fatigue as a variable (Lees and Davies, 1988). Only three studies have investigated the effect of fatigue on kicking following intermittent exercise protocols.