Cricket: Fast bowling arm actions and the illegal delivery law in

• Published in: Sports biomechanics 2006-07, Vol.5 (2), p.215-230
• Main Authors: Portus, Marc R, Rosemond, Charles D, Rath, David A
• Format: Article
• Language: English
• ISSN: 1476-3141
• DOI: 10.1080/14763140608522875

This study investigated the bowling arm kinematics of 21 elite fast bowlers (mean - SD; age = 27.8 - 3.9 years) while performing in test, tour and one day international matches. Thirty-one of the 34 deliveries analysed exhibited straightening at the elbow joint (straightening min = 3DG, max = 22DG, mean - SD = 9 - 5DG), which by strict definition in the 2000 laws of cricket made them illegal. Five deliveries from three bowlers exhibited hyperextension of the bowling elbow (19 + 5DG). When assessed against an arbitrary threshold of 15DG for elbow straightening, ball speeds for deliveries above this threshold (39.5 - 2.0 m/s) were significantly faster (effect size = 1.4; p = 0.006) than deliveries below it (37.1 - 1.4 m/s). When grouped by delivery length, the bouncers and short deliveries recorded more elbow straightening (12 - 6.6DG) than the good length deliveries (9 - 4.4DG) and the full deliveries (8 - 5.7DG), although these were not statistically significant differences. The results of this study support the implementation of a tolerance threshold for assessing the legality of fast bowling actions. Further research is recommended into in-match kinematic modelling, laboratory based assessments of illegal bowling actions, perceptual aspects of bowling actions and remedial methods to reduce elbow straightening in bowling actions.