The pathomechanics of shoulder injuries in cricket bowlers
Injury surveillance research has established that over 20 % of cricket injuries are related to the upper limb (Leary & White, 2000; Ranson & Gregory, 2008; Stretch, 2003), with bowlers associated altered rotational joint range of motion (Aginsky et al., 2004, BellJenje & Gray, 2005 and Stuelcken et al., 2008). As the applicability of such observations is limited, the aim of this thesis was to provide researchers with a greater understanding of the pathomechanics of shoulder injuries afflicting cricket bowlers though quantifying associated musculoskeletal adaptations and subsequently through the development and validation of a bowling specific kinematic model, establish the influence these may impart on bowling technique. The use of diagnostic ultrasound within the first experimental study in a cohort of bowlers without a history of shoulder injury, established a high prevalence of supraspinatus (45 %) and subscapularis (50 %) tendon pathology, providing insight into common musculotendinous pathology and adaptations that are indicative of the future potential of injury. Data presented within the second study aimed to first quantify the kinematics of the shoulder during the bowling delivery in relation to humerothoracic motion and, second, the influence of rotation sequence to described humerothoracic motion was investigated. Findings established that whilst the bowling delivery was associated with large variability, future research must acknowledge the contribution of the scapula to shoulder motion. As such, due to the complexity of quantifying shoulder motion during cricket bowling, the following three experimental studies evaluated and developed the CSBT shoulder model through modifying current methods. The mCAST method in conjunction with an acromion cluster, was established to not only reduce resultant RMSE associated with scapula landmarks by up to 0.016 m, but also increase the repeatability and robustness of reconstructing GHJ location using the SCoRE method. The emphasis of the final experimental study was to apply the CSBT shoulder model to establish the contribution of individual rotator cuff muscles to shoulder joint stability and, to identify phases of the bowling delivery which increases the risk of injury. This case study established that during the bowling delivery the shoulder experiences large multi-planar forces placing demand on musculature, in particular supraspinatus and Subscapularis to stabilise the joint. These findings in conjunction with those of the first experimental study, not only identify structures at risk of injury but also establish that for the effective formulation of injury prevention strategies the bowling delivery must be investigated in its entirety.