THE RELATION OF BALL RELEASE SPEED TO THE BIOMECHANICS OF THE ANKLE IN THE CRICKET FAST BOWLER

Abstract

Introduction: Ankle injuries in cricketers are of topical interest with a number of elite fast bowlers sustaining injuries. Previous research has concentrated on the injury risk to the bowler’s vertebrae with no research focused on the ankle of the fast bowler and exploring the biomechanical basis for its predisposition to injury.

Materials and methods: Ten elite level cricket fast bowlers had their ankle biomechanics assessed during their bowling action. Using a nine-camera infra-red ViconTM 612 motion analysis system linked to a KistlerTM 9281CA force platform the moments of the subjects leading leg ankle during their delivery stride was calculated and analysed. Each subject performed ten trials at their maximum ball release speed (> 97km/hr) and ten trials at less than their maximum ball release speed (< 97km/hr) with the velocity of the ball tracked by a SR3600 radar gun.

Results: All six joint moments of the ankle were examined in both directions of all three orthogonal planes. Of these results only the difference in the ankle plantar flexion was found to be pertinent. The average ankle plantar flexion peak moment in the maximal ball release speed group was 2.008Nm/kg and in the sub-maximal ball release speed group 1.790Nm/kg. This difference was analysed using the paired Student t-test and was statistically significant (p< 0.02).

Discussion: This study shows the ankle plays a significant part in the fast bowler’s delivery action and suggests a biomechanical reason for ankle injuries in these individuals. It is recommended that in fast bowlers with ankle injuries a graduated return to maximal speed bowling is utilised in rehabilitation to prevent further injury and long term morbidity.

Conclusion: The increased ankle plantar moment reflects the important role the ankle plays in the generation of extra ball release speed in the cricket fast bowler.