A multi-factorial evaluation of lower back injury risk factors in fast bowlers.

Fast bowlers have consistently been reported to suffer with the greatest frequency of injury, with the lower back being the most common site. The biomechanics of technique, musculoskeletal fitness and workload parameters have all been implicated in the risk of injury. Conversely, aspects of spinal morphology (spinal shrinkage and lumbar curvature) have received little attention, and thus this thesis aimed to investigate whether these should be considered as part of the multifactorial risk of injury to elite fast bowlers. The Spinal Mouse demonstrated good to high within and between day inter- and intra-rater reliability for measuring sagittal lumbar lordosis, although no acute changes were found after bowling in club standard fast bowlers. Stature measured before, during and after bowling, using a custom-built laboratory stadiometer, resulted in 5-6 mm of spinal shrinkage in club standard fast bowlers. However, this stadiometer did not provide adequate reliability for between-day intra-rater measurements and an alternative device for measuring stature changes in the field was required. The Seca 287 ultrasound stadiometer demonstrated excellent within- and between-day reliability alongside excellent concurrent validity for measuring large stature changes associated with exercise such as fast bowling. Using the Seca 287 and Spinal Mouse, spinal morphology measurements before and after bowling, were included as injury risk factors alongside three-dimensional kinematics of the bowling action, fitness measures and musculoskeletal function of 14 First-Class county cricket elite fast bowlers. A retrospective analysis of injuries over the 2019 season supported previous research demonstrating that elite fast bowlers experienced a high injury incidence. Bowlers who suffered lower back injuries experienced significantly more spinal shrinkage after five overs of bowling than those who remained injury free (8 ± 1 mm vs 4 ± 3 mm), indicating that this may be of clinical significance. Lumbar lordosis of the injured bowlers (31 ± 2°) was not significantly greater than the non-injured bowlers (25 ± 6°), although the effect size was large (r = 0.5), indicating its potential importance as an injury risk factor. Biomechanical parameters of the action, fitness measures and musculoskeletal function were not found to be related to lower back injury. Bowling and physical workload were measured across 4-day, 50 over and T20 cricket formats during the 2019 season in 10 elite bowlers, using GPS units, as additional risk factors. More deliveries were bowled in 4-day and 50 over matches when compared to T20, although adjusting for deliveries per hour resulted in no difference between formats. Intensity of bowling in T20 cricket was perceived to be lower than other game formats, although GPS metrics that calculated changes in acceleration indicated that the T20 format placed an increased intensity on the body when bowling. A lack of high intensity running and sprinting during bowling training sessions was associated with a high injury rate, although bowling workload was not associated with injury to fast bowlers. This thesis has shown that measures of spinal shrinkage and lumbar lordosis should be added to other injury risk factors measured during pre-season screening. These new risk factors should not be viewed in isolation, but as part of an approach that examines the interrelationships between the factors that could potentially lead to injury. Utilizing big data, machine learning, and a new injury model for fast bowlers may aid future research