ARTICLE IN PRESS JSHS403_proof ■ 25 May 2017 ■ 1/4 HOSTED BY Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect ScienceDirect Journal of Sport and Health Science xx (2017) 1–4 Production and hosting by Elsevier www.jshs.org.cn 1bs_bs_query Q2 Original article 2bs_bs_query 3bs_bs_query Risk factors for hamstring injuries in Australian male professional cricket 4bs_bs_query 5bs_bs_query players 6bs_bs_query Q1 a,b, b b 7bs_bs_query John Orchard *, Alex Kountouris , Kevin Sims a 8bs_bs_query School of Public Health, The University of Sydney, Sydney, NSW 2006, Australia b 9bs_bs_query Cricket Australia, Melbourne, Vic. 3002, Australia 10bs_bs_query Received 7 February 2017; revised 30 March 2017; accepted 8 April 2017 11 bs_bs_query Available online 12bs_bs_query 13bs_bs_query Abstract 14bs_bs_query 15bs_bs_query Background: Injuries to the hamstring are relatively common in professional cricketers (as they are in many team sports) and have increased in 16bs_bs_query incidence in the “T20 era” (introduction of 20-over matches) of cricket since 2006. 17bs_bs_query Methods: This study analyzed incidence of hamstring injury in the various elite male match types over a 20-year period (1995–1996 to 18bs_bs_query 2014–2015). Risk factors for hamstring strain were assessed using a multivariate logistic regression analysis technique. 19bs_bs_query Results: There were 276 match time-loss hamstring injuries recorded over a 20-year period at the Australian state or national player level, of which 20bs_bs_query 170 occurred in one of 40,145 player match sets. The overall rate of match onset rate was 22.5 hamstring injuries per 1000 team days. Fast bowling 21bs_bs_query onset injuries were the highest subcategory at a rate of 10.9 injuries per 1000 team days, although batting onset injuries were particularly common 22bs_bs_query in 50-over one day international matches. Significant risk factors in logistic regression analysis, in addition to hamstring injury history, were being 23bs_bs_query a fast bowler relative risk (RR) 2.5 (95% confidence interval (CI): 1.3–4.5) and playing a match in Australia RR 2.3 (95% CI: 1.3–3.9). 24bs_bs_query Conclusion: Fast bowlers suffer more hamstring injuries than other playing roles in cricket, particularly in First Class (multi-day) cricket. Batsmen 25bs_bs_query are more likely to get injured in 50-over (one day) cricket. Playing in Australia (compared to overseas venues) leads to increased risk of hamstring 26bs_bs_query injury. 27bs_bs_query © 2017 Production and hosting by Elsevier B.V.on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND 28bs_bs_query license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 29bs_bs_query 30bs_bs_query Keywords: Cricket; Fast bowling; Fielding; Hamstring strains; Muscle strains; Sprinting 31bs_bs_query 32bs_bs_query 1. Introduction cricket emerged: one day (or 50-over) cricket, in which each 52bs_bs_query 33bs_bs_query team’s scoring was limited to 50 overs (300 balls). This was 53bs_bs_query 34bs_bs_query Hamstring injuries have always been one of the highest followed by T20 (or 20-over) cricket (which emerged in the 54bs_bs_query 35bs_bs_query frequency injuries in cricket and have increased in incidence 1 early 2000s and became prominent at international level in 55bs_bs_query 36bs_bs_query since 2006. This time period (since 2006) coincides with the 2006), in which each team’s scoring was limited to 20 overs 56bs_bs_query 37bs_bs_query increasing prominence of the T20 format. Traditionally, cricket (120 balls for each team). A T20 match takes approximately 3 h 57bs_bs_query 38bs_bs_query has been a multi-day game where each team has 2 innings. At to complete (or half a day). The number of First Class and 58bs_bs_query 39bs_bs_query elite level the multi-day games are called “First Class” cricket 50-over matches has essentially remained the same in the T20 59bs_bs_query 40bs_bs_query and divided up into international matches (Test matches) and era, with additional T20 matches meaning that there are more 60bs_bs_query 41bs_bs_query domestic matches. The number of overs (6 bowling deliveries elite-level matches on the cricket calendar. Players can choose 61bs_bs_query 42bs_bs_query per over) that each team can face in First Class cricket is to play 1, 2, or all 3 formats of cricket, although the majority of 62bs_bs_query 43bs_bs_query unlimited—a team’s innings will continue until all 10 batsmen players typically play in all 3 formats; hence, the domestic and 63bs_bs_query 44bs_bs_query have been dismissed. This leads to potentially high workloads international matches are scheduled so that generally only one 64bs_bs_query 45bs_bs_query in the bowling unit, as the bowlers must keep bowling until they 2 format is being played at any given time. 65bs_bs_query 46bs_bs_query have dismissed the opposition. In the 1970s a second form of The Cricket Australia injury surveillance system recorded 66bs_bs_query 47bs_bs_query all match time-loss injuries sustained by Australia professional 67bs_bs_query 48bs_bs_query cricket players in domestic and international matches since 68bs_bs_query 49bs_bs_query Peer review under responsibility of Shanghai University of Sport. 1 1995–1996 season. Considering the rapid increased hamstring 69bs_bs_query 50bs_bs_query * Corresponding author. 51bs_bs_query E-mail address: [email protected] (J. Orchard) injury rate in T20 era since 2006, the purpose of this study was 70bs_bs_query http://dx.doi.org/10.1016/j.jshs.2017.05.004 2095-2546/© 2017 Production and hosting by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: John Orchard, Alex Kountouris, Kevin Sims, Risk factors for hamstring injuries in Australian male professional cricket players, Journal of Sport and Health Science (2017), doi: 10.1016/j.jshs.2017.05.004 ARTICLE IN PRESS JSHS403_proof ■ 25 May 2017 ■ 2/4 2 J. Orchard et al. 1 71bs_bs_query to assess the risk factors for sustaining hamstring injury in the number of international T20 matches is very small, which 129bs_bs_query 72bs_bs_query Australia male professional cricket players through an exami- would give an unreliable incidence rate. 130bs_bs_query 73bs_bs_query nation of hamstring injury incidences among various playing Occasions on which players sustained a hamstring strain 131bs_bs_query 74bs_bs_query roles (batting, bowling, and fielding) for different format of during a survey match were compared to those player matches 132bs_bs_query 75bs_bs_query cricket. in which no hamstring strain occurred, with risk factors used to 133bs_bs_query 76bs_bs_query predict these occurrences analyzed with a multivariate logistic 134bs_bs_query 77bs_bs_query 2. Methods regression analysis in the SPSS (Version 16; SPSS Inc., 135bs_bs_query 78bs_bs_query Chicago, IL, USA) program. The method used was forwards 136bs_bs_query 79bs_bs_query De-identified data was obtained from the Cricket Australia < > stepwise with a p 0.05 to enter and a p 0.10 to remove. The 137bs_bs_query 80bs_bs_query injury surveillance database. The Australian Government risk factors analyzed (in discrete rather than continuous catego- 138bs_bs_query 81bs_bs_query National Health and Medical Research Council Ethical 3 ries) were (1) player age, (2) primary player role, (3) history of 139bs_bs_query 82bs_bs_query Guidelines do not require ethics approval when using recent hamstring injury (earlier in the same season), (4) history 140bs_bs_query 83bs_bs_query de-identified data (negligible risk of harm). of past hamstring injury (not in the same season), (5) match 141bs_bs_query 84bs_bs_query The dataset contained information on all hamstring injuries type, and (6) year. 142bs_bs_query 85bs_bs_query that resulted in missed playing time, which included date of 143bs_bs_query 86bs_bs_query onset, match type of onset, and player details (both primary role 3. Results 144bs_bs_query 87bs_bs_query in team and role at the time of injury). Imaging such as mag- 145bs_bs_query 88bs_bs_query netic resonance imaging of injuries were not included because There were 276 match time-loss hamstring injuries, of which 146bs_bs_query 89bs_bs_query imaging was only routinely performed in the last decade. There- 170 occurred during a match under survey. The other 106 inju- 147bs_bs_query 90bs_bs_query fore, for the purposes of this study a hamstring injury was a ries occurred either during training sessions, warm-ups, lower 148bs_bs_query 91bs_bs_query clinical diagnosis made by relevant state or national medical level matches not under survey, or had an insidious onset. 149bs_bs_query 92bs_bs_query personnel. The overall match hamstring injury incidence was 22.5 inju- 150bs_bs_query 93bs_bs_query For match injury incidence, we considered match injuries ries per 1000 team days (Table 1). When incidence was calcu- 151bs_bs_query 94bs_bs_query from all playing roles combined (batting, bowling, and field- lated in team days, 50-over cricket had the highest hamstring 152bs_bs_query 95bs_bs_query ing) and the individual playing roles separately (including injury incidence (42.8 and 67.0 injuries per 1000 team days for 153bs_bs_query 96bs_bs_query fast bowling versus spin bowling and wicket keeping versus domestic and international matches, respectively) followed by 154bs_bs_query 97bs_bs_query other fielding positions). We characterized all bowling