KINETICS OF SOCCER SIDE-FOOT KICKING WITH VARIED EFFORT LEVELS

We aimed to illustrate joint kinetics during submaximal effort of soccer side-foot kicking. Side-foot kicks with three effort levels (50, 75 and 100% effort levels based on maximal effort) of eight male university soccer players were captured at 500 Hz while intial ball velocities were monitored simultaneously. Kinetic differences (angular impulses due to resultant joint moments) were clearly illustrated for hip flexion and knee extension thereby supporting the interpretation that the velocity of the distal end of the leg (foot) is controlled in a context of a proximal to distal segmental sequential system similar to instep kicks. Moreover, among joint moments responsible for out of thigh-shank plane motion, hip external rotation moment was found to be systematically adjusted between three effort levels. Additionally, an inconsistent trend was observed for hip external rotation angular velocity, suggesting some kinematic change in particular for the contribution of hip external rotation likely occured in submaximal side-foot kicks

INVESTIGATING KEY FACTORS FOR FEMALE PLAYERS TO GENERATE COMPARABLE INTERACTION TORQUE TO THAT OF MALE PLAYERS

We aimed to clarify the kinetic strategy of female players to achieve comparable motion-dependent interaction torque to that of male players during soccer instep kicking. The kicking leg motion of female and male players was captured at 500 Hz. The interaction torque was decomposed into two components due to the kicking leg and the support leg actions using the procedure of Inoue et al., (2013). Female players exhibited significantly smaller counter-clockwise (positive) interaction torque due to the support leg action while the clockwise (negative) component due to the kicking leg action was significantly suppressed in the latter part of kicking than male players. Our findings suggest coaches and female players should pay more attention to the kicking leg posture during the latter part of the leg swing to maintain their effective action of the interaction torque

ELASTIC TAPING APPLIED TO THE RECTUS FEMORIS MUSCLE ALTERS INSTEP KICKING KINEMATICS IN SOCCER

We aimed to clarify the immediate effect of an elastic taping application on the kinematics of soccer instep kicking. Fourteen male university recreational soccer players performed maximal instep kicking with and without an elastic taping applied to the rectus femoris muscle, and their kicking motions were captured using a motion capture system at 500Hz. Prior to the kicking session, the thickness of the rectus femoris muscle was measured using an ultrasound scanner. The elastic taping application significantly increased the thickness of the rectus femoris muscle. Alongside this change, initial ball velocity, peak hip flexion angular velocity, and foot linear velocities increased significantly, whereas knee extension angular velocity and hip linear velocity did not change. It is considered that the elastic taping application may enhance the function of the rectus femoris muscle, thereby inducing these kinematic changes during kicking. These findings suggested that an elastic taping application may be an effective tool to improve the performance of soccer instep kicking

COULD PLAYING SURFACE INFLUENCES CHANGE OF DIRECTION AND PERCEIVED TRACTION PERFORMANCE IN FUTSAL?

The purpose of this study was to identify differences on change of direction performance, perceived traction performance and available friction coefficient between two different futsal playing surfaces. Functional test and perceived traction evaluation were performed by twenty experienced male university level soccer players using slalom course on two different playing surfaces (area-elastic:AE and point-elastic:PE). Available friction coefficient (AFC) for each playing surface was mechanically measured using a hydraulic-powered moving force platform. In the functional test, participants were found to perform significantly better on PE when compared to AE surface (p\u3c0.001). PE surface was also found to have higher perceived traction performance (p\u3c0.001). It was suggested that significantly higher AFC observed on the PE surface compared with AE surface (p\u3c0.001) may contribute to the observed findings. This study succeeded in demonstrating the performance of change of direction run was significantly influenced by the playing surface traction and frictional properties

COMPARISON OF SUCCESS AND FAILURE IN SOCCER VOLLEY KICKING

The purpose of this study was to describe kinematic variables that can distinguish between successful (straight to the goal) and failed (over the goal) soccer volley kicking. To mimic the situation of the volley kicking, the ball was set on a paper pipe. The kicking motions of both successful and failed trials were captured from ten male university soccer players using an optical motion capture system at 500 Hz. As a result, foot–ball impact points on the ball in failed trials were concentrated around the bottom part of the ball, and the kicking motion in failed trials were characterized as: 1) smaller hip internal rotation during the back-swing, 2) more upright foot posture at ball impact and 3) more downward leg swing just before ball impact. Furthermore, it was suggested that there were several patterns of failed trials depending on the subjects