Determination and analysis of dimensions of 'feel' in tennis ball impacts

The modern style of tennis has been played for over a hundred years and although the ball has developed such that today it is a consistent product, no structured analysis has ever been undertaken to determine players' perceptions of ball qualities. This study aims to develop a comprehensive understanding of the characteristics that contribute to a player's perception of 'feel' of a tennis ball and in addition to investigate the suitability of various test procedures and data analysis methods for studies of this nature. A series of impact tests were completed to characterise the mechanical properties of selected tennis balls. A single-degree-of-freedom viscoelastic ball model was developed, and through the use of a numerical integration solution, values of stiffuess and damping, peak force and contact time were reported for impact velocities of 16- 66m/s. To establish how such differences between balls may be perceived, an interview study was completed on a group of sixteen elite tennis players in order to determine their perception of 'feel' of a tennis ball. The resulting interviews were structured to form eight dimensions of 'feel'. Two subsequent experiments were completed into the sound and vibration at impact, with both experiments capturing synchronous subjective perceptions and objective data in a realistic playing environment. In order to capture the subjective perceptions, the method of paired comparisons was adopted that allowed the reliability of the players to be evaluated through the analysis of their responses. Suitable objective metrics were determined for the analysis of sound and vibration data. Significant correlations were found between subjective perceptions and objective metrics for both sound and vibration experiments. It was found that the strongest correlations between the subjective data and objective metrics were obtained for those players deemed reliable, highlighting that generally only skilled test subjects are capable of such fine discriminations between balls.