Risk Factors for Hamstring Injuries in Australian Male Professional Cricket

ARTICLE IN PRESS JSHS403_proof ■ 25 May 2017 ■ 1/4

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1bs_bs_query Q2 Original article

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3bs_bs_query Risk factors for hamstring injuries in Australian male professional cricket

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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

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13bs_bs_query Abstract

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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.

28bs_bs_query license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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30bs_bs_query Keywords: Cricket; Fast bowling; Fielding; Hamstring strains; Muscle strains; Sprinting

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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

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all match time-loss injuries sustained by Australia professional 67bs_bs_query

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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 as T20 cricket (30.9 injuries per 1000 team days) and then First 155bs_bs_query

98bs_bs_query either fast or spin bowling, even though non-spin bowling is Class cricket (12.7 and 21.5 injuries per 1000 team days for 156bs_bs_query

99bs_bs_query sometimes divided into fast, fast-medium, and medium pace domestic and international, respectively). The incidence 157bs_bs_query

100bs_bs_query bowling. That is, bowlers considered to be medium pace ranking was the same if player days was used as the unit of 158bs_bs_query

101bs_bs_query bowlers were considered fast bowlers in this analysis (and we incident, but T20 cricket was ranked higher than 50-over cricket 159bs_bs_query

102bs_bs_query have used the term fast bowling rather than pace bowling for if player hours was the unit of injury incidence. If the unit 160bs_bs_query

103bs_bs_query clarity). chosen was player or team matches then First Class interna- 161bs_bs_query

104bs_bs_query We reported incidence in the unit of injuries per 1000 team tional cricket matches would have ranked highest (as these 162bs_bs_query

105bs_bs_query days of play. For example, 22 injuries per 1000 team days would matches last for up to 5 days). An hour of cricket led to more 163bs_bs_query

106bs_bs_query mean a team of 11 players could expect 22 match time-loss hamstring injuries in the shortest format (T20 cricket), in which 164bs_bs_query

107bs_bs_query injuries (i.e., injuries occurring in a match that resulted in a play was most intense, but a day of cricket was riskiest at the 165bs_bs_query

108bs_bs_query player being unable to perform their normal role) per 1000 team 50-over format, particularly at international level, given the 166bs_bs_query

109bs_bs_query days. This would convert to 2 injuries per 1000 player days, or combination of intensity and duration. 167bs_bs_query

110 bs_bs_query 20 injuries per 10,000 player days if a team was considered to Fast bowling had the highest incidence of hamstring injury 168bs_bs_query 4 111 bs_bs_query be 11 players. compared to the other roles in First Class cricket, which is the 169bs_bs_query

112 bs_bs_query We considered 5 different formats of match. Each of First longest format of cricket. Batting and ﬁelding had substantially 170bs_bs_query

113 bs_bs_query Class and 50-over cricket formats were separated into interna- higher incidence of hamstring injury compared to fast bowling 171bs_bs_query

114 bs_bs_query tional and domestic levels each, which resulted in 4 formats. in T20 cricket. Batting, fast bowling, and ﬁelding had substan- 172bs_bs_query

115 bs_bs_query T20 cricket was considered a combined category (both domes- tially higher incidence of hamstring injury compared to other 173bs_bs_query

116 bs_bs_query tic and international matches pooled together) as in many years roles in 50-over cricket. The incidence of hamstring injury was 174bs_bs_query

117 bs_bs_query

118 bs_bs_query Table 1

119 bs_bs_query Match injury incidence (hamstring injuries per 1000 team days) by type of match and cricket speciﬁc role.

120bs_bs_query Match Batting Fast bowling Spin bowling Fielding Wicketkeeping All*

121bs_bs_query T20 17.2 5.1 0 8.6 0 30.9

122bs_bs_query 50-over domestic 10.2 20.5 0 10.2 0.9 42.8

123bs_bs_query 50-over international (ODI) 31.3 15.6 0 13.4 0 67.0

124bs_bs_query First Class domestic 2.2 9.3 0 1.1 0 12.7

125bs_bs_query First Class international (Test) 6.1 9.2 0 4.1 0 21.5

126bs_bs_query Overall 6.6 10.9 0 4.0 0.1 22.5 = 127bs_bs_query Abbreviation: ODI one day international.

128bs_bs_query * Including those injuries with activity not speciﬁed, as a small number of hamstring injuries occurred during matches but with activity onset uncertain.

Hamstring in cricket 3

5,6 bs_bs_query Table 2 175 purely to higher intensity of play. Alternatively, the risk in 234bs_bs_query

176bs_bs_query Signiﬁcant risk factors for 170 hamstring strains occurring in 40,145 player these activities may relate to change in intensity of running 235bs_bs_query

177bs_bs_query matches in 20 years from 1995–1996 to 2014–2015 seasons, revealed by logis-

speed when players transition from longer to shorter formats of 236bs_bs_query 178bs_bs_query tic regression analysis.

the game. That is, do hamstring strains in short form cricket 237bs_bs_query

179bs_bs_query Category Risk factor RR (95% CI)

occur more readily if a player has recently been playing more 238bs_bs_query

180bs_bs_query Primary role Fast bowler compared to spin bowler 2.5 (1.3–4.5) longer form cricket and is perhaps not conditioned to higher 239bs_bs_query

181bs_bs_query Match location Match played in Australia compared to 2.3 (1.3–3.9)

intensity running? Such a phenomenon has been recently 240bs_bs_query 182bs_bs_query overseas 9 reported in Australian Football. 241bs_bs_query 183bs_bs_query Season After 2006 compared to before 2006 1.5 (1.1–2.2)

184bs_bs_query Injury history Recent history of hamstring injury 3.7 (2.5–5.5) Spin bowlers had lower injury incidence of hamstring injury 242bs_bs_query

185bs_bs_query compared to no history of hamstring injury compared to fast bowlers, which appears to be related to speed 243bs_bs_query

186bs_bs_query Past history of hamstring injury compared 2.7 (1.9–3.7) 5,6 of the run-ups indicated by GPS data in previous studies. 244bs_bs_query

187bs_bs_query to no history of hamstring injury

However, it must be considered that spin bowlers have to also 245bs_bs_query = = 188bs_bs_query Abbreviations: CI conﬁdence interval; RR relative risk. bat and ﬁeld, so while they are relatively immune from ham- 246bs_bs_query

189bs_bs_query string strain during their primary role, they are exposed in the 247bs_bs_query

190bs_bs_query minimal for spin bowling and wicketkeeping. Batting and ﬁeld- other activities of the game in which they participate. 248bs_bs_query

191bs_bs_query ing appear to have higher incidence of hamstring injury in One of the unexpected risk factors revealed is playing in 249bs_bs_query

192bs_bs_query international matches compared to domestic matches (Table 1). Australia (domestic or international matches) compared to 250bs_bs_query

193bs_bs_query There were 40,145 player matches analyzed at the domestic playing overseas. A possible explanation for this is that Austra- 251bs_bs_query

194bs_bs_query or international level, of which 170 (0.4%) led to a hamstring lian ﬁelds may be larger when compared to other countries. 252bs_bs_query

195bs_bs_query injury (Table 2). The other hamstring injuries either occurred at Smaller ﬁelds tend to lead to a higher ratio of runs being scored 253bs_bs_query

196bs_bs_query a lower level match or a training session or had a gradual or through boundaries. The minimum length of a ﬁeld is 120 m but 254bs_bs_query

197bs_bs_query uncertain pattern of onset. The risk for fast bowlers to sustain 10 Q4 the vast majority of Australian ﬁelds are 160 m long. Many of 255bs_bs_query

198bs_bs_query hamstring injury was 2.5 times higher compared to that for spin the Australian cricket ﬁelds are also used by Australian Football 256bs_bs_query

199bs_bs_query bowlers. Batsmen, wicketkeepers, and spin bowlers did not games at the same venue, which is a sport played on a much 257bs_bs_query

200bs_bs_query have a signiﬁcant difference in incidence of hamstring injury. bigger ﬁeld than the other football codes. Probably not coinci- 258bs_bs_query

201bs_bs_query There was a 3.7 times higher risk of hamstring injury in those dentally, Australian Football has a very high rate of hamstring 259bs_bs_query

202bs_bs_query who had previously suffered a hamstring injury earlier in the 11 injury compared to other football codes. The larger playing 260bs_bs_query

203bs_bs_query season, and 2.7 times higher risk for those who had history of ﬁeld probably allows players to reach higher running speeds, 261bs_bs_query

204bs_bs_query hamstring injury in previous seasons. Matches being played in 9 which possibly expose them to injury. 262bs_bs_query

205bs_bs_query Australia (either international or domestic) led to a higher risk An alternative explanation for the higher incidence of ham- 263bs_bs_query

206bs_bs_query (2.3 times) of hamstring injury than matches being played over- string injury in Australia is that fast bowlers tend to bowl more 264bs_bs_query

207bs_bs_query seas. The vast majority of the overseas matches were interna- overs than spin bowlers in Australian conditions. As they are 265bs_bs_query

208bs_bs_query tional level matches (i.e., only a very small number of domestic already the group with the highest risk of hamstring injury, the 266bs_bs_query

209bs_bs_query matches were played outside of Australia). There was a higher greater percentage of overs bowled by this group may lead to 267bs_bs_query

210bs_bs_query incidence (1.5 times) of hamstring injury in matches played the higher injury incidence. 268bs_bs_query

211bs_bs_query after 2006 (in T20 era) compared to matches played before There was a higher risk of hamstring strain in those who had 269bs_bs_query

212bs_bs_query 2006. Player age did not enter the equation as a signiﬁcant risk previously suffered a hamstring strain earlier in the season and 270bs_bs_query

213bs_bs_query factor once the other factors were taken into account. in previous seasons. This is in keeping with hamstring strain 271bs_bs_query

214bs_bs_query 11 risk factors in other sports and in contrast to oblique abdomi- 272bs_bs_query 215bs_bs_query 4. Discussion

nal injury in fast bowlers, in which recent injury is not a sig- 273bs_bs_query 216bs_bs_query 12 217bs_bs_query Although fast bowling is the activity most associated with niﬁcant risk factor. 274bs_bs_query

218bs_bs_query sustaining a hamstring injury, the T20 era has seen an increase 275bs_bs_query

bs_bs_query 219bs_bs_query in hamstring injuries related to ﬁelding and batting. The inci- 5. Conclusion 276

277bs_bs_query 220bs_bs_query dence of hamstring injuries in this study correlates quite well

This study reveals some risk factors for hamstring injury 278bs_bs_query

221bs_bs_query with numbers of sprinting efforts when measured by Great 5,6 similar to those observed in other sports (past and recent history 279bs_bs_query 222bs_bs_query Q3 Public Schools (GPS) in cricket. Fast bowlers—assessed in

of hamstring injury). There are some risk factors revealed that 280bs_bs_query

223bs_bs_query this study as having the highest incidence of hamstring strain— 5 are unique to the sport of cricket: being a fast bowler, playing in 281bs_bs_query 224bs_bs_query sprint more often than other roles in cricket. Batsmen sprint 5 Australia (on larger grounds), and playing in shorter-form 282bs_bs_query 225bs_bs_query more often in T20 and 50-over cricket than in multi-day. In

games. These additional risk factors all seem to relate some- 283bs_bs_query

226bs_bs_query multi-day cricket, the higher rate of ﬁelding hamstring injury in

what to the degree of sprinting intensity in the circumstances 284bs_bs_query

227bs_bs_query First Class international cricket seen in this study (compared to

described. That is, the more often sprinting occurs, the greater 285bs_bs_query

228bs_bs_query domestic level matches) correlates with the higher number of 6 the risk of hamstring injury. 286bs_bs_query 229bs_bs_query sprint efforts seen in international First Class matches.

287bs_bs_query

230bs_bs_query Sudden increases in workload have been associated with 7,8 Authors’ contributions 288bs_bs_query 231bs_bs_query increase in fast bowling injury in cricket. This study poses the 289bs_bs_query

232bs_bs_query question of whether increased rates of batting and ﬁelding ham- JO is the injury surveillance coordinator for Cricket Austra- 290bs_bs_query

233bs_bs_query string injuries in short form (50-over and T20) cricket is related lia under the supervision of AK and undertook the statistical 291bs_bs_query

4 J. Orchard et al.

4. Orchard JW, Ranson C, Olivier B, Dhillon M, Finch C, Gray J, et al. bs_bs_query 1292bs_bs_query analysis for the paper; KS was primarily in charge of paper 315

Consensus statement on injury surveillance in cricket: 2016 update. Br J 316bs_bs_query 293bs_bs_query revisions and response to reviewers; all authors contributing

Sports Med 2016;50:1245–51. 317bs_bs_query

294bs_bs_query substantially to the writing of the original manuscript. All 5. Petersen CJ, Pyne D, Dawson B, Portus M, Kellett A. Movement patterns 318bs_bs_query

295bs_bs_query authors have read and approved the ﬁnal version of the in cricket vary by both position and game format. J Sports Sci 2010;28: 319bs_bs_query

296bs_bs_query manuscript, and agree with the order of presentation of the 45–52. 320bs_bs_query

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movement patterns between 1-day and test cricket. J Strength Cond Res 322bs_bs_query 298bs_bs_query

2011;25:1368–73. 323bs_bs_query

299bs_bs_query Competing interests 7. Hulin BT, Gabbett TJ, Blanch P, Chapman P, Bailey D, Orchard JW. 324bs_bs_query

300bs_bs_query Spikes in acute workload are associated with increased injury risk in elite 325bs_bs_query

301bs_bs_query None of the authors declare competing ﬁnancial interests. cricket fast bowlers. Br J Sports Med 2014;48:708–12. 326bs_bs_query

302bs_bs_query 8. Orchard JW, Blanch P, Paoloni J, Kountouris A, Sims K, Orchard JJ, et al. 327bs_bs_query

Cricket fast bowling workload patterns as risk factors for tendon, muscle, 328bs_bs_query 303bs_bs_query References

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