Measuring and modelling the bounce and pace of county championship cricket pitches

The bounce of a ball (exit angle after ball impact relative to incident angle) and pace (exit speed relative to incident speed) are key characteristics which influence the competitive balance between batsman and bowler in the game of cricket. The aim of the study was to measure these playing characteristics, to identify the soil and turf factors that affect them and to determine how bounce and pace can be predicted. Over the period 1998 to 2003 a total of 92 County Championship match pitches were nominated. A standardised range of measurements were made on pitches including bounce, hardness and friction. Visual analysis was made of soil and turf features. The playing characteristics reported by umpires were assessed in relation to the pitch properties recorded. High speed video (HSV) recordings were made on twenty three of the pitches. A comparison between umpires' pitch ratings of bounce and HSV analysis indicated that umpires' assessments are quite reliable. Perceived bounce during play (by umpires) can be predicted by measured rebound resilience or hardness using a 2.25kg Clegg hammer to similar levels of reliability. Umpires' ratings of pace were not correlate with measurements of pace by HSV but were very closely correlated to their own assessments of bounce. It was concluded that visual ratings of pace by umpires are unreliable. Umpires' assessments of pace are confounded by the bounce of a pitch and therefore ball 'carry' is a dominant factor of assessment. A mathematical model was derived to predict true pace based on measurement of bounce and surface friction. The model was found to agree reasonably well with HSV analysis.