Incidence, mechanisms and risk factors for shoulder injuries in community Australian football players.
Abstract
Schwab, LM.(2020). PhD Thesis: Incidence, mechanisms and risk factors for shoulder injuries in community Australian football players. Griffith University Repository: Embargo 06/10/2021. https://doi.org/10.25904/1912/3990.
Background: Australian football is a physically demanding sport. Exposure to multidirectional body contact and the necessity for complex upper body skills can result in significant strain on regions such as the shoulder. Despite the rise in incidence and high recurrence of shoulder injuries reported at the elite Australian Football League (AFL) level there is limited evidence available to determine whether shoulder injuries are also a problem at a community level. The financial ramifications of shoulder injuries for the community AFL player and society can be considerable due to time off work, treatment costs and the high number and expense of emergency department presentations.
Objectives: The aim of this thesis was to evaluate the profile (incidence, severity, mechanisms and clinical management) of shoulder complex injuries in community-level AFL players using automated injury surveillance (SMS text messaging and online survey). The thesis also aimed to investigate whether factors identified during preseason (i.e. musculoskeletal screening, measurement of habitual activity levels, or in-season training workload) were related to shoulder, head or neck time-loss injuries.
Methods: Study 1 and 2 prospectively evaluated a novel, automated method of injury surveillance in community AFL players (during a 20-week season) to assess method feasibility (Chapter 3) and to evaluate the profile of shoulder injuries (Chapter 4). In study 3, video footage of elite AFL players (n = 26) retrospectively examined the biomechanical aetiology of injuries to the shoulder complex (Chapter 5). The final two prospective cohort studies (4 and 5) examined potential risk factors for upper body injuries with similar injury mechanisms. At baseline, community AFL players were assessed using seven screening tests of the upper body, trunk and whole-body function to identify any relationships with in-season injuries to the shoulder, head, or neck (Chapter 6). Screening reference values were also determined. Pre-season habitual activity levels and in-season training workloads were collected to prospectively identify associations with in-season injuries to the upper or lower body regions (Chapter 7).
Results: The automated method of injury surveillance was deemed feasible for reporting injuries in community AFL players. The incidence of injuries to the shoulder complex was reported to be high (2nd highest in matches, 4th overall; 10.4% of all injuries). The severity of these shoulder injuries was mostly mild (<3 games missed), but a substantial number required medical attention (emergency department or doctor). Results also indicated activity mechanisms of injury were body region dependent with the majority of upper body injuries (shoulder, head and neck) due to collision contact. Injuries common to lower body regions (thigh, knee and ankle) were from non-contact/ overuse mechanisms. Video analysis of biomechanical aetiology identified that the majority of shoulder injuries occurred with the arm below 100 degrees flexion/ abduction and were caused by lateral contact (34.6%) and hyperflexion/ abduction (19.2%) mechanisms; potentially unavoidable contact injuries. This study found limited evidence to support the use of the suite of musculoskeletal screening tests selected for the upper body, trunk and whole-body function to identify risk of in-season injuries to the shoulder, head or neck. Furthermore, the results identified the variable nature of total workload characteristics in community AFL players, however, no total workload relationships were identified with common in-season injuries to the upper or lower body.
Conclusions: Shoulder injuries are problematic for community AFL players and the use of feasible methods of injury surveillance may help overcome the challenges associated with collecting shoulder injury data in community team sport. The musculoskeletal screening tests and measures of training and habitual workload selected and investigated in this thesis, however, were unable to adequately detect players ‘at-risk’ of an in-season injury to the shoulder, head or neck region. Future studies could investigate different intrinsic risk factors to the ones selected in this study and results also suggest that examination of extrinsic factors (such as rule changes) could possibly be indicated with an aim of preventing shoulder injuries. Furthermore, results from video analysis of elite players may suggest that prophylactic strategies should be customised to the positions of shoulder injury and also focus on lateral contact injury prevention in community AFL players. Findings from this thesis may help to inform the development of injury prevention strategies and guide future research directions with an aim of decreasing injuries to the shoulder complex in community AFL players.
