In recent years variability in behaviour of the sliotar, a small leather-bound ball used in the Irish sport of hurling, became evident in championship matches. The current standard has not provided adequate repeatability of ball performance. A new method for assessing the dynamic impact behaviour of approved sliotar cores has been characterised. This test system was developed to measure the performance characteristics, such as coefficient of restitution, deformation and contact time, and the viscoelastic properties of dynamic stiffness and hysteresis energy dissipation. In this paper, the relationship between the viscoelastic properties and the coefficient of restitution is presented.