The curve kick of a football

The first part of the study used a computer simulation model to examine how foot-impact location and friction affect the launch characteristics of a football during a curve kick. The spin of the ball was found to increase with both the off-set distance between the foot and ball axis and the coefficient of friction. A trade-off was found between the ball velocity and spin, for different off-set distances.

The second part of the study examined the aerodynamic properties of a football during flight. The launch conditions and subsequent trajectory of fired balls were measured using two high speed video cameras and drag and lift coefficients were calculated for each test, based on a trajectory model. Simulations of various kicking scenarios demonstrated that a ball is struck in the centre will follow a near straight trajectory. A ball that is stuck off-centre will bend before reaching the goal with a significantly longer flight time. If friction between the boot and ball is reduced , possibly caused by wet conditions, the imparted spin will be less and the ball will not bend as much in flight.