An evaluation of biomechanical measures of bowling action legality in cricket

Abstract

Cricket bowling is traditionally thought to be a rigid-arm motion, allowing no elbow straightening during the delivery phase. Conversely, research has shown that a perfectly rigid arm through delivery is practically unattainable, which has led to rule changes over the past years. The current rule requires a bowler not to increase the elbow angle by more than 15 degrees, thus requiring a measurement to confirm legality in "suspect" bowlers. The aims of this study were to evaluate whether the current rule is maintained over a range of bowlers and bowling styles, and to ascertain whether other kinematics measures may better differentiate between legal and suspect bowling actions. Eighty-three bowlers of varying pace were analysed using reflective markers and a high-speed (240 Hz) eight-camera motion analysis system in a laboratory. The change in elbow segment angle (minimum angle between the arm and forearm), the change in elbow extension angle with respect to the flexion-extension axis of a joint coordinate system, and the elbow extension angular velocity at ball release were measured. We found that bowlers generally bowled within a change in elbow extension angle of 15.5 degrees. However, this limit was unable to differentiate groups of bowlers from those who were suspected of throwing in the past. Improved differentiation was attained using the elbow extension angular velocity at ball release. The elbow extension angular velocity at ball release may be conceptually more valid than the elbow extension angle in determining which bowlers use the velocity-contributing mechanisms of a throw. Also, a high value of elbow extension angular velocity at ball release may be related to the visual impression of throwing. Therefore, it is recommended that researchers and cricket legislators examine the feasibility of specifying a limit to the elbow extension angular velocity at ball release to determine bowling legality.

The influence of elbow joint kinematics on wrist speed in cricket fast bowling

“…However, Ferdinands and Kersting (2007) found that elbow joint angular displacement could not differentiate between participants who had been previously suspected of "throwing". The authors suggested that using the velocity of elbow extension at ball release would be a conceptually more valid measure in identifying bowlers that use this velocity component of throwing to their advantage.…”

Illegal bowling actions contribute to performance in cricket finger‐spin bowlers

“…While research examining the area of illegal actions in cricket has been undertaken, the primary focus has involved quantifying or exploring improved methods for the accurate measurement of elbow kinematics . While this research has explored important issues, the underlying and fundamental question, what is the relationship between elbow extension values and known performance benefits, has yet to be sufficiently answered.…”

“…It will also provide support staff with knowledge that will allow better coaching of bowlers, while also facilitating remediation of bowlers with illegal actions. To date, research attempting to explore the performance benefits of bowling with an illegal action has been limited to small bowling cohorts, in‐silico modeling of the effect of elbow fixed flexion, or simple planar analysis of fast bowling …”

“…ball revolutions, cricket, finger-spin bowling, illegal action quantifying or exploring improved methods for the accurate measurement of elbow kinematics. [5][6][7][8][9][10][11][12][13][14][15] While this research has explored important issues, the underlying and fundamental question, what is the relationship between elbow extension values and known performance benefits, 16 has yet to be sufficiently answered. Further, perhaps other biomechanical variables (other than elbow extension) discriminate bowlers who deliver the ball with an illegal, compared with a legal action.…”

Sports Medicine and Indian Cricket: Exploring the Past, understanding the Present and accommodating a Future of Scientific Conception

“…29 To add on, another research study compared twodimensional (2D) video analysis with 3D motion analysis to assess fast bowling action of Indian male university level fast bowlers. 30 The concept of biomechanical analysis is still quite new to Indian cricket compared to other cricketing nations where there have been numerous research studies conducted over the past decade, such as Dr Rene Ferdinands' investigations which include the use of 3D motion analysis system to assess lumbar segment kine matics of fast bowlers, 31 evaluating biomechanical measures of fast bowling to differentiate between legal and suspect bowling actions 32 and more recently, examining the dynamics of spin bowling using a smart cricket ball and a cortex motion analysis system. 33 Research on biomechanical aspects of the game of cricket in India is relatively new.…”