Cricket

Abstract

In this study we analysed technique, ball speed and trunk injury data collected at the Australian Institute of Sport (AIS) from 42 high performance male fast bowlers over a four year period. We found several notable technique inter-relationships, technique and ball speed relationships, and associations between technique and trunk injuries. A more front-on shoulder alignment at back foot contact was significantly related to increased shoulder counter-rotation (p < 0.001). Bowlers who released the ball at greater speeds had an extended front knee, or extended their front knee, during the front foot contact phase (p < 0.05). They also recorded higher braking and vertical impact forces during the front foot contact phase and developed those forces more rapidly (p < or =0.05). A maximum hip-shoulder separation angle occurring later in the delivery stride (p = 0.05) and a larger shoulder rotation to ball release (p = 0.05) were also characteristics of faster bowlers. Bowlers suffering lower back injuries exhibited typical characteristics of the 'mixed' technique. Specifically, the hip to shoulder separation angle at back foot contact was greater in bowlers who reported soft tissue injuries than in non trunk-injured bowlers (p = 0.03), and shoulder counter-rotation was significantly higher in bowlers who reported lumbar spine stress fractures than non trunk-injured bowlers (p = 0.01). The stress fracture group was also characterised by a larger hip angle at front foot contact and ball release, whereas a more flexed front knee at ball release characterised the non trunk-injured group.

Different tissue type categories of overuse injuries to cricket fast bowlers have different severity and incidence which varies with age

“…[8,10] Biomechanical research is often conducted on adolescent or young fast bowlers [6,11] or does not clearly identify the demographics of the injured vs. non-injured groups. [10] So it is unclear whether the risk factor of poor technique (excessive shoulder counterrotation) continues into the older age groups. [12] In a previous paper these authors demonstrated that different injuries to cricket fast bowlers classified by the structure injured (bone, muscle, tendon, joint) had different types of loading histories that were either protective or risky.…”

Relationships Between Fast Bowling Technique and Ball Release Speed in Cricket

“…A bowler facing directly down the wicket (front-on) was defined to have a shoulder and pelvis projection angle of 270°, standing in a purely side-on position corresponded to a projection angle of 180°. 5 Shoulder girdle forward-rotation was defined as the change in shoulder projection angle from the most side-on position to the orientation at BR. The pelvisshoulder separation angle was calculated by subtracting the pelvis projection angle from the shoulder projection angle.…”

“…5 However, a correlation between ball release speed and the timing of the maximum pelvis-shoulder separation angle during the delivery stride was observed. 5 Those bowlers whose maximum separation angle occurred later in the delivery action (relative to the instant of front foot contact, FFC) bowled faster. Similarly the position of the arm at FFC was a good predictor of release speed, with faster bowlers delaying the onset of arm circumduction.…”

“…10 A link between increased shoulder girdle and upper trunk rotation (shoulder girdle forward rotation) preceding ball release (BR) and faster release speed has been reported. 5 Increased flexion of the trunk (between FFC and BR) has also been reported to provide a significant contribution to ball release speed, contributing an estimated 11-13% of the final release speed. 6,11 A number of studies have identified links between the position of the arm (and ball) at the instant of ball release and the release speed.…”

“…3,4 Similarly, faster bowlers have been observed to have larger amounts of front knee extension during the period from full foot contact (front foot flat, FFF) until ball release. 5 It has been suggested that a front knee that extends, or is already extended, during the front foot contact phase may permit a more efficient transfer of energy to the ball and facilitate faster ball release speeds. [5][6][7] However, there is currently no firm agreement regarding the importance of the motion of the front knee in determining ball release speed.…”