A method for calculating and interpreting the ratio of friction force to normal force imparted on a spherical object: Application to a cricket ball during bowling.

This article focuses on a novel method for calculating the coefficient of friction (COF) between fingers and a cricket ball during spin bowling, using the spin parameter derived from angular and translational velocities measured via a motion analysis system. The method involves force-fitting a rigid master triangle to marker triad data to reduce noise without relying on low-pass filtering, which was found to worsen data accuracy. Applying this approach to different types of cricket spin deliveries revealed that wrist-spin deliveries exhibit a higher COF than finger-spin deliveries, with no significant COF difference between topspin and backspin; additionally, deliveries with the palm pointing medially showed greater COF than those with the palm pointing laterally. The findings suggest a new functional classification of spin bowling deliveries based on COF, offering potential strategic insights for coaching and performance enhancement in cricket spin bowling.