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The incidence of behaviours associated with body checking among youth ice hockey players
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Journal of Science and Medicine in Sport 15 (2012) 463–467
Original research
The incidence of behaviours associated with body checking among youth ice hockey players Simon Malenfant a , Claude Goulet a,∗ , Luc Nadeau a , Denis Hamel c , Carolyn A. Emery b b
a Laval University, Department of Physical Education, Faculty of Education, Québec, Canada Sport Medicine Centre, Roger Jackson Centre for Health and Wellness Research, University of Calgary, Faculty of Kinesiology, Calgary, Canada c Québec Public Health Institute, Québec, Canada
Received 6 July 2011; received in revised form 9 February 2012; accepted 3 March 2012
Abstract Objectives: To determine if a difference exists between the incidence and intensity of the physical contacts of Pee Wee (aged 11–12 years) ice hockey players according to whether the players participate in a league in which body checking is permitted (Calgary, Canada) compared to a league in which body checking is not permitted (Québec City, Canada). Design: Cohort study conducted in Québec City and Calgary during the 2007–2008 Pee Wee ice hockey season. Methods: Ten games were randomly selected for each city (n = 20) and analysed. Games were videotaped and subsequently analysed with a validated observation system allowing quantification of the intensity of the various physical contacts. Incidence rate ratios (RR) based on multivariate Poisson regression were used to compare the physical contacts between provinces. All analyses were controlling for game period, score difference, and zone on the playing surface. Results: A total of 2418 physical contacts with the trunk and 757 other physical contacts were observed. Very light intensity trunk physical contacts were more frequent in Québec City (adjusted incidence RR [ARR]: 0.68; 95% CI: 0.48–0.97). Very high intensity trunk physical contacts were more frequent in Calgary (ARR: 12.72; 95% CI: 4.48–36.14). Hooking (ARR: 0.89; 95% CI: 0.84–0.95) and slashing (ARR: 0.91; 95% CI: 0.85–0.97) were more frequent in Québec City. Conclusions: Results suggest that players’ behaviours are different in leagues where body checking is permitted compared to leagues where it is not permitted. Policy allowing body checking in Pee Wee ice hockey increases the frequency and intensity of physical contacts. © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. Keywords: Ice hockey; Behaviours; Physical contacts; Body checking; Prevention; Athletic injury
1. Introduction With more than 577,000 players registered in Hockey Canada, ice hockey is one of the most popular sports in Canada.1 In 2010, there were over 100,000 registered players in the province of Québec and over 64,000 registered players in the province of Alberta.1 Despite the health benefits of youth ice hockey participation, the frequency of injury associated with this sport raises concern.2–4 Studies suggest that ice ∗ Corresponding author at: Department of Physical Education, Faculty of Education, Pavillon de l’Éducation physique et des sports, 2300, rue de la Terrasse, local 2176, Université Laval Québec, Québec, G1V 0A6 Canada. Tel.: +1 418 656 3870; fax: +1 418 656 3020. E-mail address: [email protected] (C. Goulet).
hockey injuries account for 10% of all youth sport injuries and furthermore physical contacts, which include body checking (BC), are the principal injury mechanism in this sport.2,3,5 BC has been associated with 45–86% of injuries among youth ice hockey players.6,7 Hockey Canada defines BC as an individual defensive tactic designed to stop the progression or to separate the puck carrier from the puck.8 This tactic is the result of a defensive player applying physical extension of the body toward the puck carrier moving in an opposite direction. The action of the defensive player is deliberate and forceful in a different direction to which the offensive player is moving and is not solely determined by the movement of the puck carrier. Thus, the defensive player uses force as a tactic to modify the offensive player’s trajectory.
1440-2440/$ – see front matter © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jsams.2012.03.003
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The ice hockey community (coaches, sports experts, administrators, and practitioners) does not support one universal position regarding the introduction of BC in youth ice hockey. The opponents of early BC are concerned with the risk of injury and concussion specifically in young growing players.4 They suggest that the introduction of BC should occur when players are at a certain level of physical maturity. The opponents to early BC also argue that the early introduction of BC significantly contributes to an increase in violence in youth ice hockey.9,10 They observe that the sub-culture of violence inherent from BC does not help the harmonious development of youth ice hockey players.10 Opponents to early BC argue that BC is used as a tool of intimidation rather than a tactical defensive measure to slow down the opponent progression.10,11 On the other hand, for the early BC enthusiasts, BC is arguably an important part of the game at elite levels. Secondly, it is argued that if the players learn BC at young age, they will be protected from injury as they mature, and will become better players. Finally, they suggest that players will have more fun playing the game of ice hockey with BC.2,4,12 Recently, two Canadian studies brought research evidence to support some claims of the opponents to early exposition to body checking.6,13 The first study has examined if the risk of injury and concussion was different for similar Pee Wee (aged 11–12 years) ice hockey players in leagues where BC was permitted (Alberta) compared to leagues where BC was not permitted (Québec). Players’ level of play, rules of play and referee qualifications did not differ between provinces other than the rule allowing BC in Alberta and not in Québec. The outcomes indicate a greater than 3-fold increased risk of concussion, injury, severe concussion, and severe injury in games played in Pee Wee leagues in which BC was permitted compared to similar leagues in which BC was not permitted.6 As mentioned earlier, BC enthusiasts argue that if Pee Wee players learn BC, they will be protected from injury when they will get to the next category, that is Bantam (aged 13–14 years). Therefore, a Bantam cohort study13 followed the aforementioned Pee Wee study.6 The authors examined whether the risk of concussion and other injury among players in Bantam leagues differed between players with (Alberta) and those without (Québec) BC experience in Pee Wee. The results demonstrated that there is no increased risk of injury or concussion in a Bantam league where BC is introduced in Bantam compared to a league where players have two years of BC experience.13 In the province of Québec, BC is not allowed until elite bantam level (13–14 years old). It is the only province in Canada to do so. This policy is based in part on the research of Régnier and colleagues who demonstrated that allowing younger children to BC resulted in more penalties, more injuries and more aggressive play.3 The increasing risk of injury appears to be related to an important difference in height, weight and force of impact
between players in the same age groups.3 Thus, the authors suggested that these differences were explained by the great variability in the fast and sudden growth acceleration between players. The policies allowing BC at the Pee Wee level in Alberta and the Bantam level in Québec provided a unique opportunity to examine whether the incidence, the intensity, and the type of physical contacts (PC) differ for Pee Wee ice hockey players in a league that permits body checking vs a league that does not. There is clear evidence that shows that playing in a league where BC is permitted is associated with a significant increased risk of game-related injuries.6 But, the association between BC regulation and the incidence, the intensity, and the type of physical contacts (PC) is less well known. The hypotheses stated for this study are that the incidence and the intensity of the PC will be greater in leagues where BC is permitted, and that the type of PC will be different in both leagues. 2. Methods A prospective cohort study was conducted over one season of play (October 2007–March 2008). Cohorts were defined by their exposure to a league with rules that permitted BC (Calgary, Alberta, Canada) or not (Québec City, Québec, Canada). Teams in the top 10% by level of play were randomly selected in the Calgary (9 of the 27 teams; 33%), and Québec City (14 of the 34 teams; 41%) league. Since these teams were randomly selected, this sample of teams can be considered as representative of the teams playing in each league. Inclusion criteria were the following: teams formed with players aged 11–12 years during the season of play; male or female players; players registered with Hockey Calgary or Hockey Québec; teams play in elite division for each areas. Elite teams were selected to ensure the lowest variability possible in the level of play between teams in each cohort. Ten games were randomly selected and analysed for each cohort, for a total of 20 games, representing 5% of the games played in both cohorts. The representativity of this sample of games lies in the random selection of games. Most ice hockey studies in past years used game sheet reports to assess the occurrence of specific behaviours, for example the number and type of penalties per game.10,14,15 Contrary to past studies that used only game sheet reports, direct observation made by trained research assistants was used in the present study to better reflect the reality of the course of the game, and to allow the assessment of the PC. Based on the work of Nadeau and his colleagues, an observation system was validated to analyse PC occurring during games.16 During video viewing, for each PC, a research assistant had to record different characteristics of the PC. Table 1 presents these characteristics. To determine the location of the PC, the playing rink was delimited in five zones as presented in Fig. 1.
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Table 1 Characteristics of the physical contacts (PC) observed. Outcome
Measurements
Type of physical contact
Made with the trunk (level of intensity 1–5) Other contact with the limbs or a hockey stick Slashing, hooking, pushing
Who provide the PC
Defensive player Offensive player Puck carrier Non puck carrier
Intension of the player when doing the PC
Deliberate Non deliberate
The PC performed with the trunk were scored based on 5 levels of intensity. They are defined as: Level 1 refers to very light physical contact between players who are not moving forward. Players routinely battle for the puck along the boards or after a face-off. With this type of contact, it is sometimes difficult to distinguish between the puck carrier and the non-puck carrier, or to determine whether the player is offensive or defensive. Level 2 refers to light physical contact between two players skating in the same direction. The intention is to impede the progress of the opposing player, who is slightly or not at all affected by the contact. Level 3 refers to moderate physical contact between two players skating in the same direction. The intention is to impede the progress of the opposing player, who is moderately or totally affected by the contact. Level 4 physical contact occurs when a player applies a forceful physical extension of the body to an opposing player, who is usually skating in the opposite direction. The opposing player is moderately or totally affected by the contact. It corresponds to a heavy intensity PC. Level 5 physical contact occurs when a player deliberately extends toward an opposing player, who is usually skating in the opposite direction, in order to initiate contact and hit with excessive force. The intention is more than simply to impede the progress of the opponent, who is totally affected by the contact. PC of levels 4 and 5 correspond to BC as defined by Hockey Canada.8 SAS version 9.2 (SAS Institute Inc., Cary, NC) was used for the statistical analyses. Incidence rates were based on number of PC per team-game. Crude and adjusted incidence rate ratio (RR) based on multivariate Poisson regression were used to compare games played in Calgary and Québec City. To obtain valid estimates, RRs were adjusted for period of play (first, second, third), zone on the playing surface (Fig. 1), and score difference (0–1 goal, 2 or more). The data were also analysed using Generalized Estimating Equations (GEE) accounting for potential cluster effect (games). Over dispersion of data were also considered, using a Negative Binomial Distribution. Significance was based on α < 0.05. Approval
Fig. 1. Definition of the zones on the playing surface. Numbers indicate the zones where a physical contact may occur.
was granted by the Research Ethics Committee in Health Sciences at Laval University (approval number: 2007-134 A-1).
3. Results A total of 2418 physical contacts with the trunk and 757 physical contacts with a limb or a hockey stick were observed. As presented in Table 2, significant differences between provinces were observed in the rate of PC per team-game. Teams in Calgary had more frequent physical contacts than teams in Québec City (adjusted incidence rate ratio [ARR]: 1.39; 95% CI: 1.03–1.88). Differences were also observed when PC were distributed by intensity. Significant differences were observed between the two regions for PC of intensity 1, 3, 4, and 5. Very light intensity PC (level 1) were more frequent in Québec City (ARR: 0.68; 95% CI: 0.48–0.97). Moderate intensity PC of level 3 (ARR: 1.80; 95% CI: 1.34–2.44), heavy intensity PC of level 4 (ARR: 7.01; 95% CI: 3.43–14.33) and excessive intensity PC of level 5 (ARR: 12.72; 95% CI: 4.48–36.14) were more frequent in Calgary. PC made by a defensive player (ARR: 1.58; 95% CI: 1.22–2.04) were more frequent in Calgary. Non-deliberate PC (ARR: 0.29; 95% CI: 0.11–0.76) were more frequent in Québec City. There was no statistical difference for the zone where the PC were made on the playing surface. We observed that most of the PC were made in zone 1 and in zone 5, along the board and in front of the goal. Players were using mostly the board to restrict the puck carrier progression, and in zone 5, players protecting the front of the goal (analyses not reported). Global rates of the other PC made with a limb or a hockey stick did not show significant differences between the two regions (Table 2). Differences were observed when PC were distributed by type. Hooking with a hockey stick (ARR: 0.89; 95% CI: 0.84–0.95) and slashing with a hockey stick (ARR:
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0.91; 95% CI: 0.85–0.97) were more frequent in Québec City.
4. Discussion Our results suggest that the rate of PC was different in leagues where BC was allowed compared to leagues where it was not allowed. As expected, more PC were observed in Calgary, where BC was permitted. Furthermore, Table 2 shows that the intensity of the PC made with the trunk was greater in leagues where BC was allowed. Therefore, Pee Wee ice hockey players in Calgary were more exposed to moderate to excessive intensity PC than players playing in Québec City. The quantity and type of PC were significantly different between leagues in the two cities. When BC was allowed, players were able to use physical opposition, which resulted in higher intensity physical contacts. In Québec City, BC was not permitted; therefore, more PC of very light intensity were observed, especially at face-off and when players battled for the puck along the board. Furthermore, our results suggest that players in Calgary were using the board to restrict the puck carrier progression and, in zone 5, players were protecting the front of the goal. MacPherson et al. have found that the rates of injuries were increased among young players when BC was allowed.2 Emery et al. have found an increased rate of injuries and concussion in young Pee Wee ice hockey players who were playing with BC.6 Thus, our results suggest that a higher intensity in PC may be related to an increased risk of injury and concussion in Alberta compared with Québec. In Calgary, the defensive players were more likely to favour PC against their opponents (Table 2). Non puck carrier
players were prone to use PC toward players in possession of the puck. The types of PC varied in both regions (Table 2). Québec City players used hooking and slashing behaviours more than Calgary players. Those actions were indirectly used to limit the progression of the opponents. In Québec City, players used those actions to slow down the opponent’s progression. Since the rules did not permit BC, the players avoided this technique to limit the opponent’s progression to elude being penalized. The action of hooking was considered as a tactical action for limiting the progression of the opponent.10 The action of slashing with a hockey stick was observed when the player tried to take possession of the puck from an opponent. The player hits the legs and the opponent’s ice hockey stick with his/her own stick. To limit the progression of the offensive player, the defensive player used the action of slashing with his/her hockey stick. Thus, this action can also be considered as a tactical action for limiting the progression of the opponent. The limitations of our study should be discussed. First, there is no reason to believe that the sample of analysed games (N = 20), nor the total of PC observed (n = 3175) were not representative of the type of ice hockey played in Calgary and Québec City for teams in the top 10% by level of play. The limited number of games observed on the other hand could reduce the power of the analyses. Nevertheless, interesting differences were found related to the characteristics of the PC made with the trunk and the other types of PC. Furthermore, some PC may not have been observed or recorded by the research assistant because of the poor image quality of the video or PC made in a camera’s dead angle. But there is no reason to believe that a systematic selection bias associated with those missed actions occurred.
Table 2 Characteristics of the physical contacts (PC) made with the trunk and other PC made by Pee Wee ice hockey players in leagues in Québec City and in leagues in Calgary (2007–2008). Québec City (N/team-game) Intensity of PC with the trunka All 56.7 Level 1 28.4 18.2 Level 2 Level 3 8.5 1.4 Level 4 0.15 Level 5 PC with the trunk made 14.3 By an offensive player 42.4 By a defensive player On a puck carrier 24.3 32.3 On a nun puck carrier 3.0 Non delibarate Other PC 18.1 All 8.6 Pushing with a limb 5.8 Hooking with a hockey stick 3.7 Slashing with a hockey stick a b c
Calgary (N/team-game)
RR (95% CI)b
ARR (95% CI)c
p-Value for ARR
64.0 17.8 18.2 15.1 9.9 1.9
1.13 (0.88–1.45) 0.63 (0.43–0.90) 1.00 (0.74–1.53) 1.78 (1.32–2.37) 7.07 (3.54–14.00) 12.67 (4.45–36.05)
1.39 (1.03–1.88) 0.68 (0.48–0.97) 1.23 (0.83–1.81) 1.80 (1.34–2.44) 7.01 (3.43–14.33) 12.72 (4.48–36.14)
0.03 0.03 0.30 0.0001 <0.0001 <0.0001
7.9 56.1 35.2 28.8 0.8
0.55 (0.25–1.22) 1.32 (1.07–1.64) 1.45 (0.79–2.66) 0.88 (0.45–1.75) 0.27 (0.10–0.75)
0.63 (0.28–1.41) 1.58 (1.22–2.04) 1.64 (0.90–3.01) 1.14 (0.57–2.27) 0.29 (0.11–0.76)
0.26 0.0005 0.11 0.71 0.01
19.6 16.3 2.4 0.9
1.08 (0.74–1.57) 1.90 (1.09–3.29) 0.41 (0.23–0.75) 0.24 (0.11–0.55)
1.05 (0.76–1.46) 1.29 (0.99–1.68) 0.89 (0.84–0.95) 0.91 (0.85–0.97)
0.77 0.06 0.0005 0.01
Intensity as define in Section 2. RR, incidence rate ratio Calgary vs Québec City; CI, confidence interval. ARR, incidence rate ratio Calgary vs Québec City adjusted for game period, score difference, and zone on the playing surface; CI, confidence interval.
S. Malenfant et al. / Journal of Science and Medicine in Sport 15 (2012) 463–467
The teams were randomly selected and the observers were regularly reviewed by the principal investigator to assess the level of agreement between observers on the different categories of PC. Moreover, we were not able to measure the intention of the players just before the PC occurred and thus we cannot know the players’ intent of the PC (i.e. to limit the progression of the opponent or to cause harm). Also, the issue of the game score and the general standing of the teams were unknown. The observation system did not allow for measurement of the impact of these two variables. Finally, the quality of player skill was not assessed despite the fact that a skillful player might play differently than a low skilled player. Therefore, we were not able to report if players in leagues where BC was permitted played differently than those in leagues without BC. Further studies are necessary to compare the skill level of players playing with or without BC. 5. Conclusion These results suggest that higher intensity, higher frequency and different types of PC are observed in Pee Wee leagues where BC is permitted when comparing to Pee Wee leagues where BC is not permitted. Thus, policy-allowing BC seems to affect the frequency, the intensity and the type of PC during Pee Wee ice hockey games.
6. Practical implications • Administrators must take into account the higher intensity and different types of physical contact when decisions are to be made with regard to the introduction of body checking. • Coaches must know that BC leads to higher injury rates due to the higher frequency, intensity and the difference in type of PC and adapt their teaching of body checking accordingly. • Coaches must know that the rate of hooking and slashing behaviours is greater in leagues where BC is not allowed and adapt their teaching of body checking accordingly.
Acknowledgements This study was financially supported by the ministère de l’Éducation, du Loisir et du Sport du Québec [Québec Ministry of Education, Leisure, and Sport], the Canadian Institutes of Health Research, and the Max Bell Foundation.
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We also wish to thank the study coordinators and research assistants for their assistance in completing this research. Without the support of players, parents, coaches and administrators in Hockey Calgary and Hockey Québec, this work would not have been possible.
References 1. Hockey Canada Annual Report. 2010. Available at: http://www.hockeycanada.ca/index.php/ci id/55192/la id/1.htm. Accessed 12 August 2010. 2. Macpherson A, Rothman L, Howard A. Body-checking rules and childhood injuries in ice hockey. Pediatrics 2006;117(2):143–147. 3. Régnier G, Boileau R, Marcotte G, et al. Effects of body-checking in Pee Wee (12 and 13 years old) division in the Province of Québec. In: Hoerner EF, editor. Safety in ice hockey. Philadelphia: American Society for Testing and Materials; 1989. 4. Marchie A, Cusimano MD. Bodychecking and concussions in ice hockey: should our youth pay the price? Can Med Assoc J 2003;169(2):124–128. 5. Emery CA, Hagel B, Decloe M, et al. Risk factors for injury and severe injury in youth ice hockey: a systematic review of the literature. Inj Prev 2010;16(2):113–118. 6. Emery CA, Kang J, Shrier I, et al. Risk of injury associated with body checking among youth ice hockey players. J Am Med Assoc 2010;303(22):2265–2272. 7. Darling SR, Schaubel DE, Baker JG, et al. Intentional versus unintentional contact as a mechanism of injury in youth ice hockey. Br J Sports Med 2011;45(6):492–497. 8. Hockey Canada, Background on Checking. 2009. Available at: http://www.hockeycanada.ca/6/8/6/2/index1.shtml. Accessed 12 August 2010. 9. Robidoux MA, Trudel P. Hockey Canada and the bodychecking debate in minor hockey. In: Artificial ice: hockey, culture, and commerce. Peterborough: Garamond Imprint; 2006. 10. Trudel P, Bernard D, Boileau R, et al. The study of performance and aggressive behaviors of ice hockey players. In: Hoerner EF, editor. Safety in Ice Hockey, vol. 2. Philadelphia: American Society for Testing and Materials; 1993. 11. Colburn K. Deviance and legitimacy in ice hockey – a microstructural theory of violence. Sociol Quart 1986;27(1):63–74. 12. Goodman D, Gaetz M, Meichenbaum D. Concussions in hockey: there is cause for concern. Med Sci Sports Exerc 2001;33(12):2004–2009. 13. Emery CA, Kang J, Shrier I, et al. The risk of injury associated with body checking experience in youth ice hockey players. Can Med Assoc J 2011;183(11):1249–1256. 14. Bernard D, Trudel P, Marcotte G, et al. The incidence, types, and circumstances of injuries to ice hockey players at the bantam level (14 to 15 years old). In: Hoerner EF, editor. Safety in ice hockey, vol. 2. Philadelphia: American Society for Testing and Materials; 1993. 15. Trudel P, Dionne JP, Bernard D. Differences between assessments of penalties in ice hockey by referees, coaches, players, and parents. In: Ashare AF, editor. Safety in ice hockey, vol. 3. Philadelphia: American Society for Testing and Materials; 2000. 16. Nadeau L, Godbout P, Richard JF. Assessment of ice hockey performance in real-game condition. Eur J Sport Sci 2008;8(6):379–388.
Journal of Science and Medicine in Sport 15 (2012) 463–467
Original research
The incidence of behaviours associated with body checking among youth ice hockey players Simon Malenfant a , Claude Goulet a,∗ , Luc Nadeau a , Denis Hamel c , Carolyn A. Emery b b
a Laval University, Department of Physical Education, Faculty of Education, Québec, Canada Sport Medicine Centre, Roger Jackson Centre for Health and Wellness Research, University of Calgary, Faculty of Kinesiology, Calgary, Canada c Québec Public Health Institute, Québec, Canada
Received 6 July 2011; received in revised form 9 February 2012; accepted 3 March 2012
Abstract Objectives: To determine if a difference exists between the incidence and intensity of the physical contacts of Pee Wee (aged 11–12 years) ice hockey players according to whether the players participate in a league in which body checking is permitted (Calgary, Canada) compared to a league in which body checking is not permitted (Québec City, Canada). Design: Cohort study conducted in Québec City and Calgary during the 2007–2008 Pee Wee ice hockey season. Methods: Ten games were randomly selected for each city (n = 20) and analysed. Games were videotaped and subsequently analysed with a validated observation system allowing quantification of the intensity of the various physical contacts. Incidence rate ratios (RR) based on multivariate Poisson regression were used to compare the physical contacts between provinces. All analyses were controlling for game period, score difference, and zone on the playing surface. Results: A total of 2418 physical contacts with the trunk and 757 other physical contacts were observed. Very light intensity trunk physical contacts were more frequent in Québec City (adjusted incidence RR [ARR]: 0.68; 95% CI: 0.48–0.97). Very high intensity trunk physical contacts were more frequent in Calgary (ARR: 12.72; 95% CI: 4.48–36.14). Hooking (ARR: 0.89; 95% CI: 0.84–0.95) and slashing (ARR: 0.91; 95% CI: 0.85–0.97) were more frequent in Québec City. Conclusions: Results suggest that players’ behaviours are different in leagues where body checking is permitted compared to leagues where it is not permitted. Policy allowing body checking in Pee Wee ice hockey increases the frequency and intensity of physical contacts. © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. Keywords: Ice hockey; Behaviours; Physical contacts; Body checking; Prevention; Athletic injury
1. Introduction With more than 577,000 players registered in Hockey Canada, ice hockey is one of the most popular sports in Canada.1 In 2010, there were over 100,000 registered players in the province of Québec and over 64,000 registered players in the province of Alberta.1 Despite the health benefits of youth ice hockey participation, the frequency of injury associated with this sport raises concern.2–4 Studies suggest that ice ∗ Corresponding author at: Department of Physical Education, Faculty of Education, Pavillon de l’Éducation physique et des sports, 2300, rue de la Terrasse, local 2176, Université Laval Québec, Québec, G1V 0A6 Canada. Tel.: +1 418 656 3870; fax: +1 418 656 3020. E-mail address: [email protected] (C. Goulet).
hockey injuries account for 10% of all youth sport injuries and furthermore physical contacts, which include body checking (BC), are the principal injury mechanism in this sport.2,3,5 BC has been associated with 45–86% of injuries among youth ice hockey players.6,7 Hockey Canada defines BC as an individual defensive tactic designed to stop the progression or to separate the puck carrier from the puck.8 This tactic is the result of a defensive player applying physical extension of the body toward the puck carrier moving in an opposite direction. The action of the defensive player is deliberate and forceful in a different direction to which the offensive player is moving and is not solely determined by the movement of the puck carrier. Thus, the defensive player uses force as a tactic to modify the offensive player’s trajectory.
1440-2440/$ – see front matter © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jsams.2012.03.003
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The ice hockey community (coaches, sports experts, administrators, and practitioners) does not support one universal position regarding the introduction of BC in youth ice hockey. The opponents of early BC are concerned with the risk of injury and concussion specifically in young growing players.4 They suggest that the introduction of BC should occur when players are at a certain level of physical maturity. The opponents to early BC also argue that the early introduction of BC significantly contributes to an increase in violence in youth ice hockey.9,10 They observe that the sub-culture of violence inherent from BC does not help the harmonious development of youth ice hockey players.10 Opponents to early BC argue that BC is used as a tool of intimidation rather than a tactical defensive measure to slow down the opponent progression.10,11 On the other hand, for the early BC enthusiasts, BC is arguably an important part of the game at elite levels. Secondly, it is argued that if the players learn BC at young age, they will be protected from injury as they mature, and will become better players. Finally, they suggest that players will have more fun playing the game of ice hockey with BC.2,4,12 Recently, two Canadian studies brought research evidence to support some claims of the opponents to early exposition to body checking.6,13 The first study has examined if the risk of injury and concussion was different for similar Pee Wee (aged 11–12 years) ice hockey players in leagues where BC was permitted (Alberta) compared to leagues where BC was not permitted (Québec). Players’ level of play, rules of play and referee qualifications did not differ between provinces other than the rule allowing BC in Alberta and not in Québec. The outcomes indicate a greater than 3-fold increased risk of concussion, injury, severe concussion, and severe injury in games played in Pee Wee leagues in which BC was permitted compared to similar leagues in which BC was not permitted.6 As mentioned earlier, BC enthusiasts argue that if Pee Wee players learn BC, they will be protected from injury when they will get to the next category, that is Bantam (aged 13–14 years). Therefore, a Bantam cohort study13 followed the aforementioned Pee Wee study.6 The authors examined whether the risk of concussion and other injury among players in Bantam leagues differed between players with (Alberta) and those without (Québec) BC experience in Pee Wee. The results demonstrated that there is no increased risk of injury or concussion in a Bantam league where BC is introduced in Bantam compared to a league where players have two years of BC experience.13 In the province of Québec, BC is not allowed until elite bantam level (13–14 years old). It is the only province in Canada to do so. This policy is based in part on the research of Régnier and colleagues who demonstrated that allowing younger children to BC resulted in more penalties, more injuries and more aggressive play.3 The increasing risk of injury appears to be related to an important difference in height, weight and force of impact
between players in the same age groups.3 Thus, the authors suggested that these differences were explained by the great variability in the fast and sudden growth acceleration between players. The policies allowing BC at the Pee Wee level in Alberta and the Bantam level in Québec provided a unique opportunity to examine whether the incidence, the intensity, and the type of physical contacts (PC) differ for Pee Wee ice hockey players in a league that permits body checking vs a league that does not. There is clear evidence that shows that playing in a league where BC is permitted is associated with a significant increased risk of game-related injuries.6 But, the association between BC regulation and the incidence, the intensity, and the type of physical contacts (PC) is less well known. The hypotheses stated for this study are that the incidence and the intensity of the PC will be greater in leagues where BC is permitted, and that the type of PC will be different in both leagues. 2. Methods A prospective cohort study was conducted over one season of play (October 2007–March 2008). Cohorts were defined by their exposure to a league with rules that permitted BC (Calgary, Alberta, Canada) or not (Québec City, Québec, Canada). Teams in the top 10% by level of play were randomly selected in the Calgary (9 of the 27 teams; 33%), and Québec City (14 of the 34 teams; 41%) league. Since these teams were randomly selected, this sample of teams can be considered as representative of the teams playing in each league. Inclusion criteria were the following: teams formed with players aged 11–12 years during the season of play; male or female players; players registered with Hockey Calgary or Hockey Québec; teams play in elite division for each areas. Elite teams were selected to ensure the lowest variability possible in the level of play between teams in each cohort. Ten games were randomly selected and analysed for each cohort, for a total of 20 games, representing 5% of the games played in both cohorts. The representativity of this sample of games lies in the random selection of games. Most ice hockey studies in past years used game sheet reports to assess the occurrence of specific behaviours, for example the number and type of penalties per game.10,14,15 Contrary to past studies that used only game sheet reports, direct observation made by trained research assistants was used in the present study to better reflect the reality of the course of the game, and to allow the assessment of the PC. Based on the work of Nadeau and his colleagues, an observation system was validated to analyse PC occurring during games.16 During video viewing, for each PC, a research assistant had to record different characteristics of the PC. Table 1 presents these characteristics. To determine the location of the PC, the playing rink was delimited in five zones as presented in Fig. 1.
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Table 1 Characteristics of the physical contacts (PC) observed. Outcome
Measurements
Type of physical contact
Made with the trunk (level of intensity 1–5) Other contact with the limbs or a hockey stick Slashing, hooking, pushing
Who provide the PC
Defensive player Offensive player Puck carrier Non puck carrier
Intension of the player when doing the PC
Deliberate Non deliberate
The PC performed with the trunk were scored based on 5 levels of intensity. They are defined as: Level 1 refers to very light physical contact between players who are not moving forward. Players routinely battle for the puck along the boards or after a face-off. With this type of contact, it is sometimes difficult to distinguish between the puck carrier and the non-puck carrier, or to determine whether the player is offensive or defensive. Level 2 refers to light physical contact between two players skating in the same direction. The intention is to impede the progress of the opposing player, who is slightly or not at all affected by the contact. Level 3 refers to moderate physical contact between two players skating in the same direction. The intention is to impede the progress of the opposing player, who is moderately or totally affected by the contact. Level 4 physical contact occurs when a player applies a forceful physical extension of the body to an opposing player, who is usually skating in the opposite direction. The opposing player is moderately or totally affected by the contact. It corresponds to a heavy intensity PC. Level 5 physical contact occurs when a player deliberately extends toward an opposing player, who is usually skating in the opposite direction, in order to initiate contact and hit with excessive force. The intention is more than simply to impede the progress of the opponent, who is totally affected by the contact. PC of levels 4 and 5 correspond to BC as defined by Hockey Canada.8 SAS version 9.2 (SAS Institute Inc., Cary, NC) was used for the statistical analyses. Incidence rates were based on number of PC per team-game. Crude and adjusted incidence rate ratio (RR) based on multivariate Poisson regression were used to compare games played in Calgary and Québec City. To obtain valid estimates, RRs were adjusted for period of play (first, second, third), zone on the playing surface (Fig. 1), and score difference (0–1 goal, 2 or more). The data were also analysed using Generalized Estimating Equations (GEE) accounting for potential cluster effect (games). Over dispersion of data were also considered, using a Negative Binomial Distribution. Significance was based on α < 0.05. Approval
Fig. 1. Definition of the zones on the playing surface. Numbers indicate the zones where a physical contact may occur.
was granted by the Research Ethics Committee in Health Sciences at Laval University (approval number: 2007-134 A-1).
3. Results A total of 2418 physical contacts with the trunk and 757 physical contacts with a limb or a hockey stick were observed. As presented in Table 2, significant differences between provinces were observed in the rate of PC per team-game. Teams in Calgary had more frequent physical contacts than teams in Québec City (adjusted incidence rate ratio [ARR]: 1.39; 95% CI: 1.03–1.88). Differences were also observed when PC were distributed by intensity. Significant differences were observed between the two regions for PC of intensity 1, 3, 4, and 5. Very light intensity PC (level 1) were more frequent in Québec City (ARR: 0.68; 95% CI: 0.48–0.97). Moderate intensity PC of level 3 (ARR: 1.80; 95% CI: 1.34–2.44), heavy intensity PC of level 4 (ARR: 7.01; 95% CI: 3.43–14.33) and excessive intensity PC of level 5 (ARR: 12.72; 95% CI: 4.48–36.14) were more frequent in Calgary. PC made by a defensive player (ARR: 1.58; 95% CI: 1.22–2.04) were more frequent in Calgary. Non-deliberate PC (ARR: 0.29; 95% CI: 0.11–0.76) were more frequent in Québec City. There was no statistical difference for the zone where the PC were made on the playing surface. We observed that most of the PC were made in zone 1 and in zone 5, along the board and in front of the goal. Players were using mostly the board to restrict the puck carrier progression, and in zone 5, players protecting the front of the goal (analyses not reported). Global rates of the other PC made with a limb or a hockey stick did not show significant differences between the two regions (Table 2). Differences were observed when PC were distributed by type. Hooking with a hockey stick (ARR: 0.89; 95% CI: 0.84–0.95) and slashing with a hockey stick (ARR:
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0.91; 95% CI: 0.85–0.97) were more frequent in Québec City.
4. Discussion Our results suggest that the rate of PC was different in leagues where BC was allowed compared to leagues where it was not allowed. As expected, more PC were observed in Calgary, where BC was permitted. Furthermore, Table 2 shows that the intensity of the PC made with the trunk was greater in leagues where BC was allowed. Therefore, Pee Wee ice hockey players in Calgary were more exposed to moderate to excessive intensity PC than players playing in Québec City. The quantity and type of PC were significantly different between leagues in the two cities. When BC was allowed, players were able to use physical opposition, which resulted in higher intensity physical contacts. In Québec City, BC was not permitted; therefore, more PC of very light intensity were observed, especially at face-off and when players battled for the puck along the board. Furthermore, our results suggest that players in Calgary were using the board to restrict the puck carrier progression and, in zone 5, players were protecting the front of the goal. MacPherson et al. have found that the rates of injuries were increased among young players when BC was allowed.2 Emery et al. have found an increased rate of injuries and concussion in young Pee Wee ice hockey players who were playing with BC.6 Thus, our results suggest that a higher intensity in PC may be related to an increased risk of injury and concussion in Alberta compared with Québec. In Calgary, the defensive players were more likely to favour PC against their opponents (Table 2). Non puck carrier
players were prone to use PC toward players in possession of the puck. The types of PC varied in both regions (Table 2). Québec City players used hooking and slashing behaviours more than Calgary players. Those actions were indirectly used to limit the progression of the opponents. In Québec City, players used those actions to slow down the opponent’s progression. Since the rules did not permit BC, the players avoided this technique to limit the opponent’s progression to elude being penalized. The action of hooking was considered as a tactical action for limiting the progression of the opponent.10 The action of slashing with a hockey stick was observed when the player tried to take possession of the puck from an opponent. The player hits the legs and the opponent’s ice hockey stick with his/her own stick. To limit the progression of the offensive player, the defensive player used the action of slashing with his/her hockey stick. Thus, this action can also be considered as a tactical action for limiting the progression of the opponent. The limitations of our study should be discussed. First, there is no reason to believe that the sample of analysed games (N = 20), nor the total of PC observed (n = 3175) were not representative of the type of ice hockey played in Calgary and Québec City for teams in the top 10% by level of play. The limited number of games observed on the other hand could reduce the power of the analyses. Nevertheless, interesting differences were found related to the characteristics of the PC made with the trunk and the other types of PC. Furthermore, some PC may not have been observed or recorded by the research assistant because of the poor image quality of the video or PC made in a camera’s dead angle. But there is no reason to believe that a systematic selection bias associated with those missed actions occurred.
Table 2 Characteristics of the physical contacts (PC) made with the trunk and other PC made by Pee Wee ice hockey players in leagues in Québec City and in leagues in Calgary (2007–2008). Québec City (N/team-game) Intensity of PC with the trunka All 56.7 Level 1 28.4 18.2 Level 2 Level 3 8.5 1.4 Level 4 0.15 Level 5 PC with the trunk made 14.3 By an offensive player 42.4 By a defensive player On a puck carrier 24.3 32.3 On a nun puck carrier 3.0 Non delibarate Other PC 18.1 All 8.6 Pushing with a limb 5.8 Hooking with a hockey stick 3.7 Slashing with a hockey stick a b c
Calgary (N/team-game)
RR (95% CI)b
ARR (95% CI)c
p-Value for ARR
64.0 17.8 18.2 15.1 9.9 1.9
1.13 (0.88–1.45) 0.63 (0.43–0.90) 1.00 (0.74–1.53) 1.78 (1.32–2.37) 7.07 (3.54–14.00) 12.67 (4.45–36.05)
1.39 (1.03–1.88) 0.68 (0.48–0.97) 1.23 (0.83–1.81) 1.80 (1.34–2.44) 7.01 (3.43–14.33) 12.72 (4.48–36.14)
0.03 0.03 0.30 0.0001 <0.0001 <0.0001
7.9 56.1 35.2 28.8 0.8
0.55 (0.25–1.22) 1.32 (1.07–1.64) 1.45 (0.79–2.66) 0.88 (0.45–1.75) 0.27 (0.10–0.75)
0.63 (0.28–1.41) 1.58 (1.22–2.04) 1.64 (0.90–3.01) 1.14 (0.57–2.27) 0.29 (0.11–0.76)
0.26 0.0005 0.11 0.71 0.01
19.6 16.3 2.4 0.9
1.08 (0.74–1.57) 1.90 (1.09–3.29) 0.41 (0.23–0.75) 0.24 (0.11–0.55)
1.05 (0.76–1.46) 1.29 (0.99–1.68) 0.89 (0.84–0.95) 0.91 (0.85–0.97)
0.77 0.06 0.0005 0.01
Intensity as define in Section 2. RR, incidence rate ratio Calgary vs Québec City; CI, confidence interval. ARR, incidence rate ratio Calgary vs Québec City adjusted for game period, score difference, and zone on the playing surface; CI, confidence interval.
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The teams were randomly selected and the observers were regularly reviewed by the principal investigator to assess the level of agreement between observers on the different categories of PC. Moreover, we were not able to measure the intention of the players just before the PC occurred and thus we cannot know the players’ intent of the PC (i.e. to limit the progression of the opponent or to cause harm). Also, the issue of the game score and the general standing of the teams were unknown. The observation system did not allow for measurement of the impact of these two variables. Finally, the quality of player skill was not assessed despite the fact that a skillful player might play differently than a low skilled player. Therefore, we were not able to report if players in leagues where BC was permitted played differently than those in leagues without BC. Further studies are necessary to compare the skill level of players playing with or without BC. 5. Conclusion These results suggest that higher intensity, higher frequency and different types of PC are observed in Pee Wee leagues where BC is permitted when comparing to Pee Wee leagues where BC is not permitted. Thus, policy-allowing BC seems to affect the frequency, the intensity and the type of PC during Pee Wee ice hockey games.
6. Practical implications • Administrators must take into account the higher intensity and different types of physical contact when decisions are to be made with regard to the introduction of body checking. • Coaches must know that BC leads to higher injury rates due to the higher frequency, intensity and the difference in type of PC and adapt their teaching of body checking accordingly. • Coaches must know that the rate of hooking and slashing behaviours is greater in leagues where BC is not allowed and adapt their teaching of body checking accordingly.
Acknowledgements This study was financially supported by the ministère de l’Éducation, du Loisir et du Sport du Québec [Québec Ministry of Education, Leisure, and Sport], the Canadian Institutes of Health Research, and the Max Bell Foundation.
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We also wish to thank the study coordinators and research assistants for their assistance in completing this research. Without the support of players, parents, coaches and administrators in Hockey Calgary and Hockey Québec, this work would not have been possible.
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