Role of Friction on the Ability of Goalkeeper to Catch Soccer Ball

The objective of this research is to improve the performance of the goalkeeper in catching soccer ball. This can be achieved by investigating the static friction displayed by the soccer ball and the top layer of the goalkeeper glove, goalkeeper hand skin as well as his short sleeve jersey under dry and water wet conditions. Besides, the comfort of the goalkeeper depends on the electrostatic charge (ESC) generated from the triboelectrification of ball, gloves and jersey of the goalkeeper. ESC was measured for the sliding of the tested materials. It was observed that, at dry and wet sliding, backhand of the glove showed higher friction than the palm. The friction values guaranteed good ability for the goalkeeper to catch the ball. Friction coefficient displayed by the ball sliding on jersey of the goalkeeper showed the lowest values.That observation increases the danger of ball slip when it touches the jersey of the goalkeeper. In contradiction to that, sliding of the ball on the hand skin displayed higher friction coefficient compared to that observed for sliding on the jersey. Backhand of the glove gained higher ESC than palm at both dry and wet sliding. The ball surface at dry and wet sliding conditions gained positive ESC of relatively lower values. ESC generated from sliding the ball on the jersey generated very high values and migrated to the goalkeeper body. ESC values generated from sliding of the ball on hand skin were lower than that recorded for sliding against jersey. After more rubbing, the jersey gains more charge. Then the goalkeeper will be subjected to high intensity of electric field. This observation confirmed the necessity to develop new materials of low ESC.