Is bowling workload a risk factor for injury to Australian junior cricket fast bowlers?

OBJECTIVES: To examine whether bowling workload is a risk factor for overuse injury to Australian junior cricket fast bowlers and to evaluate the appropriateness of current bowling workload guidelines. METHODS: Forty four male fast bowlers (mean (standard deviation) age 14.7 (1.4) years) were monitored prospectively over the 2002-2003 season. Bowlers completed a daily diary to record bowling workloads and self reported injuries, which were validated by a physiotherapist. Bowling workload prior to the first injury (for those bowlers who were injured) was compared to workload across the whole season for uninjured bowlers. RESULTS: Eleven (25%) bowlers reported an overuse-type injury, with seven of these sustaining a back injury. Injured bowlers had been bowling significantly more frequently than uninjured bowlers (median number of days since the previous bowling day: 3.2 v 3.9 days, Mann-Whitney U = 105.0, p = 0.038). Compared with bowlers with an average of > or =3.5 rest days between bowling, bowlers with an average of <3.5 rest days were at a significantly increased risk of injury (risk ratio (RR) = 3.1, 95% confidence interval (CI) 1.1 to 8.9). There were also trends towards an increased risk of injury for those who bowled an average of > or =2.5 days per week (RR = 2.5, 95% CI 0.9 to 7.4) or > or =50 deliveries per day (RR = 2.0, 95% CI 0.7 to 5.4). CONCLUSIONS: This study has identified high bowling workload as a risk factor for overuse injury to junior fast bowlers. Continued research is required to provide scientific evidence for bowling workload guidelines that are age-specific for junior fast bowlers.

Cricket fast bowling performance and technique and the influence of selected physical factors during an 8-over spell.

The aims of this study were to determine the influence of an 8-over spell on cricket fast bowling technique and performance (speed and accuracy), and to establish the relationship of selected physical capacities with technique and performance during an 8-over spell. Fourteen first-grade fast bowlers with a mean age of 23 years participated in the study. Physical capacities assessed were abdominal strength, trunk stability, selected girth and skinfold measures. During the delivery stride, bowlers were filmed from an overhead and lateral perspective (50 Hz) to obtain two-dimensional data for transverse plane shoulder alignment and sagittal plane knee joint angle respectively. Ball speed was measured by a radar gun and accuracy by the impact point of each delivery on a zoned scoring target at the batter's stumps. Shoulder counter-rotation did not change significantly between overs 2 and 8 for all bowlers, but was significantly related to a more front-on shoulder orientation at back foot impact. When the front-on fast bowlers (n = 5) were isolated for analysis, shoulder counter-rotation increased significantly between overs 2 and 8. Ball speed remained constant while accuracy showed some non-significant variation during the spell. Shoulder counter-rotation was significantly related to accuracy scores during the second half of the 8-over spell. Chest girth and composition and body composition were significantly related to ball release speed at various times during the spell.