title: Fast bowling arm actions and the illegal delivery law in men's high performance cricket matches.
abstract: 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 = 3 degrees, max = 22 degrees, mean +/- SD = 9 +/- 5 degrees), 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 +/- 5 degrees). When assessed against an arbitrary threshold of 15 degrees 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 +/- 6.6 degrees) than the good length deliveries (9 +/- 4.4 degrees) and the full deliveries (8 +/- 5.7 degrees), 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.
authors.affiliation: Cricket Australia, Jolimont, Victoria.
authors.forename: Marc R
authors.initials: MR
authors.lastname: Portus
authors.forename: Charles D
authors.initials: CD
authors.lastname: Rosemond
authors.forename: David A
authors.initials: DA
authors.lastname: Rath
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000379:methods*; D004550:Elbow / Q000502:physiology*; D004594:Electrophysiology; D015444:Exercise / Q000502:physiology; D006801:Humans; D016059:Range of Motion, Articular; D012399:Rotation; D013177:Sports / Q000502:physiology*; D013647:Task Performance and Analysis; D014741:Video Recording; D014953:Wrist / Q000502:physiology