Constant parameter visco-elastic model of a normal incidence football impact

The FIFA (Fédération Internationale de Football Association) Quality Programme was established in 1996 to standardise the quality of playing equipment used in competitions [1]. The programme assesses the physical properties of a football (e.g., mass, circumference, and sphericity) and dynamic performance (e.g., rebound height from a 2 m drop). There are over 1,000 football models approved for use in competitive play [2]. The combination of materials, joining technique and the outer-panelling design contribute to the overall mechanical properties of the football and will alter the dynamic response of the ball [3]. Quantitative knowledge of the mechanical properties of footballs is important in the development of standards to maintain football performance in match play, to ensure that developments in sports equipment do not adversely change the
nature of the game.