Shoulder injuries of cricket fast bowlers in New Zealand. (2020)
Type of ContentElectronic Thesis or Dissertation
Thesis DisciplineHealth Sciences
Degree NameDoctor of Philosophy
PublisherUniversity of Canterbury
AuthorsWalter, Sibi Boycott Noelshow all
Cricket is predominantly a summer sport enjoyed by all age groups and has a high participation rate, across the globe. The likelihood for injury exposure is high, given the popularity of playing cricket. Therefore, injury surveillance is essential to quantify and subsequently design preventive measures to reduce injury prevalence. The studies encompassing this thesis were conducted according to van Mechelenís sports injury prevention model. The first three studies identified and quantified the extent and aetiology of cricket injuries across different performance levels, and the remaining two studies introduced preventive measures.
The first study quantified and classified cricket-related injuries in the resident New Zealand population. Cricket-related injury claim data from 2005-2016, were obtained from New Zealandís Accident Compensation Corporation and classified by injured body area, injury type and diagnosis. Based on the NZ population censuses, the age-standardised injury incidence (ASII) per 10,000 people-years was calculated using the Segi world standard for each calendar year. Results showed that the ASII for cricket injuries increased by 42% over the 12 year period. The hand/wrist (19.7 %), back/spine (15.7%) and shoulder (11.2%) were the three most injured body parts. Soft tissue injuries (76%) were the most prevalent injury, and 69% of all injuries were due to contact. The 31% non-contact injuries are likely due to repetitive and strenuous movements. One limitation of this study was that the injury onset was described generically rather than linking it to a specific cricket activity. The spine and shoulder areas experienced the greatest increase in injury prevalence over the 12 years, so it could be argued that soft tissue injuries to the spine and shoulder require special attention. The second study aimed to identify the most common activity being undertaken during injury onset in elite cricketers. This was achieved by analysing the results of media-based injury surveillance conducted during the 2015 Cricket World Cup (CWC) One-Day Tournament. During the 49 tournament matches, a total of 31 injuries were recorded. Of these, fast bowlers (12) and batsmen (11) had a similar number of injuries, but fast bowlers missed eight more matches (31) than batsmen (23). Among the 219 tournament players, nine (4%) were injured while bowling in matches, nine (4%) were injured during training and six (3%) while batting in matches.
In the results of study 1, it was identified that shoulders were one of the most commonly injured body parts and injuries were mostly due to non-contact repetitive strenuous movement. While in study 2, it was identified that fast bowling was a highly injury-prone cricketing position. Amongst existing cricket injury studies, very few explore shoulder injuries. So the third study was aimed at finding out where fast bowlers get injured and to identify the specific diagnoses of those injuries. Hence, study 3 was conducted using retrospective 12-month injury surveillance of 35 domestic New Zealand fast bowlers. These fast bowlers had an injury prevalence of 71% (25/35). The four most injury-prone areas were the lower back (19%), ankle/feet (15%), thigh (15%) and the shoulders (13%). The injury-specific diagnoses for the 13% shoulder injuries involved the rotator cuff and the subacromial space.
Stages 1 and 2 of the sports injury prevention model proposed by van Mechelen recommends quantification of injury extent and identifying its aetiology. The results of studies 1-3 highlighted the extent of cricket-related shoulder injury prevalence and identified the fast bowling position as the most injury-prone while describing the most common injury diagnoses for elite fast bowlers.
Repetitive bowling and throwing involve shoulder abduction and rotation. The rotator cuff muscles are the primary agonists for shoulder abduction and rotation. High bowling and throwing workloads combined with decreased rest periods weakens the rotator cuff muscle strength and affects glenohumeral stability. Asymmetries in glenohumeral range of motion and rotator cuff muscle strength can lead to anatomical changes in the shoulder joint which can manifest as chronic shoulder pain. Assessment of range of motion and rotator cuff muscle strength may identify the shoulder jointís functional restrictions and potentially could be used to predict injury risk.
Study 4 measures aimed at comparing the glenohumeral range of motion (ROM) and shoulder- rotator muscle strength between fast bowlers with and without shoulder pain. Subjective reporting and objective screening were undertaken for shoulder pain, while shoulder rotators muscle strength and glenohumeral rotational ROM was measured. Overall, 35% of fast bowlers experienced shoulder pain, and these bowlers exhibited a slight trend of lower ROM in comparison to their uninjured counterparts; IR ROM (injured 76 ± 8°, uninjured 79 ± 9°); ER ROM (injured 81 ± 12°, uninjured 86 ± 5°). Regardless of a shoulder injury, all bowlers exhibited slightly weaker external rotators in comparison to their internal rotators on their dominant side (IR, 42 ± 8 N.m; ER 39 ± 6 N.m). Although there was not a significant difference in strength between the internal and external rotators, previous shoulder injury research literature suggests that weaker external rotators are associated with the superior-anterior translation of the humerus and reduction in subacromial space. Strengthening the rotator cuff will help restore glenohumeral stability, resist humeral translation and limit subacromial impingement.
Stage 3 of van Mechelenís model suggests the introduction of preventive measures aimed at reducing injury occurrence. Therefore, a shoulder exercise programme was designed to strengthen the rotator cuff, which may potentially help prevent shoulder injuries. Study 5ís objective was to observe the effects of a 6-week Indian clubbell (ICB) exercise programme on shoulder range of motion and isometric muscle strength of fast bowlers. A total of 21 healthy male fast bowlers were pair-matched on their initial shoulder-rotator isometric muscle strength (IMS) and assigned to either an ICB shoulder strengthening group or a cricket training only group. The ICB group underwent a 6-week shoulder-rotator strengthening programme. Bilateral internal rotators IMS increased in the ICB group from baseline to week 6 (P<0.05). The ICB groupís non-dominant arm internal rotation (IR) ROM also increased (64 ± 10° to 70 ± 6°, P<0.05), while the posterior shoulder tightness decreased (31 ± 4° to 37 ± 3°, P<0.05). There was no significant increase in the external rotatorís strength. Rotator cuff strength is vital for positioning the humeral head in the glenohumeral joint. Stronger internal rotators and weaker external rotators may also cause superior-anterior translation of the humeral head. Thereby reducing the subacromial space and leading to impingement of its soft tissues. To create an effective shoulder injury prevention programme, the focus has to be on strengthening the shoulder rotators with special attention given to the external rotators.
In summary, study 1 identified that non-contact shoulder injuries in cricket occur mostly due to repetitive and strenuous movements. Study 2 found that fast bowling was the main activity during the onset of injuries. Study 3 revealed that fast bowlerís shoulder injuries involve the rotator cuff and subacromial space. Study 4 assessed the shoulders of injured fast bowlers and lastly study 5 introduced an exercise programme to strengthen the rotator cuff and potentially reduce shoulder injuries. All these thesis studies were conducted according to the stages proposed by van Mechelenís sports injury prevention model. The first three studies quantified the extent of the problem pertaining to cricket-related shoulder injuries and established injury aetiology. The last two studies investigated and introduced preventive measures aimed at reducing shoulder injuries. Future research should seek to conduct long term injury surveillance among fast bowlers to correlate shoulder injury incidence with an Indian clubbell exercise programme, and this would tie into the recommendation of stage 4 of the sports injury prevention model. Based on the beneficial outcomes of study 5, regular participation in an Indian clubbell exercise programme will help maintain shoulder ROM and strengthen the rotator cuff. Future investigation is required to assess the hypothesis that this will reduce shoulder overuse injury incidence.