Injury Rate and Pattern Among Elite World Cup Snowboarders
Injury Rate and Pattern Among Elite World Cup Snowboarders
We recorded injuries through the FIS ISS based on annual retrospective athlete interviews during six WC seasons (2007–2012). A methodological study has shown that retrospective interviews were the best method to register injuries, compared to prospective injury registration by FIS technical delegates and team medical personnel. Athletes on the WC teams from Austria, Canada, Finland, France, Germany, Italy, Norway and Sweden were interviewed. During the study period, we also included athletes from 23 other teams to increase the study population. The team had to have a response rate of 80% or more to be included. All the athletes included were registered in the FIS database and had started in at least one FIS WC competition.
All interviews were conducted at the end of each season in person by physicians or physiotherapists from the Oslo Sports Trauma Research Center in the finishing area or during organised meetings at the competitor hotel. We completed a standardised interview form for each athlete, where each athlete was asked to consent to participating in the FIS ISS. If the athlete reported an injury, an injury form was also completed. The injury form consisted of information about the date and place of injury, injury circumstances, body part injured, side (left/right), injury type, injury severity and the specific diagnosis. If an athlete was not present at the event, due to injury or other reason, or if the athlete did not understand English, the team coach, physician or physiotherapist was interviewed. If the athlete was injured at the time of the interview, we used the physician's prognosis to classify the severity of the injury.
We defined injuries as "all acute injuries that occurred during training or competition and required attention by medical personnel." The injury definition and the classification of body parts and injury types used in the injury form was based on a consensus document on injury surveillance in football. We classified the severity of the injuries, according to the duration of absence from training and competition, as follows: slight (no absence), minimal (1–3 days), mild (4–7 days), moderate (8–28 days) and severe (>28 days).
To calculate exposure, we obtained the exact number of started runs by each of the athletes interviewed from the official FIS competition database (http://www.fis-ski.com) for each of the six seasons (2007–2012). The result list for each of the WC races during the six seasons was extracted one by one from the FIS database online into an Excel file. Specific variables were added to the result for each of the athletes, that is, date, discipline, place and sex. In addition, we created a new variable to calculate the number of started runs for each athlete per competition. The exposure data in the Excel file were transferred to our database (Oracle Database 11g, Oracle Corporation, California, USA) where we linked the exposure data for each of the athletes to the information recorded through the interviews. We calculated total exposure, as well as exposure for males versus females and for each of the different snowboarding disciplines.
The injury rate was expressed as the absolute injury rate (injuries per 100 athletes per season) and the relative injury rate (injuries per 1000 runs) with the corresponding 95% CI. When calculating the absolute injury rate we included all recorded injuries, while we only included injuries in official WC, World Snowboard Championship (WSC) and OWG competitions when calculating the relative injury rate, as the number of runs started (exposure) was only available for these events. A total of 15 injuries reported to have occurred in competition could not be attributed to the event reported (HP: n=6, PGS/PSL: n=1, SBX: n=8). We included these in our analysis of the absolute injury rate, as it seems quite likely that these injuries occurred in training prior to the competition rather than in the competition itself. Calculations were based on the Poisson model, and Z tests were used to compare the injury rate and injury pattern between groups. The rate ratio (RR) with 95% CI was computed. A two-tailed p level of <0.05 was considered to be statistically significant.
Material and Methods
Study Design and Population
We recorded injuries through the FIS ISS based on annual retrospective athlete interviews during six WC seasons (2007–2012). A methodological study has shown that retrospective interviews were the best method to register injuries, compared to prospective injury registration by FIS technical delegates and team medical personnel. Athletes on the WC teams from Austria, Canada, Finland, France, Germany, Italy, Norway and Sweden were interviewed. During the study period, we also included athletes from 23 other teams to increase the study population. The team had to have a response rate of 80% or more to be included. All the athletes included were registered in the FIS database and had started in at least one FIS WC competition.
All interviews were conducted at the end of each season in person by physicians or physiotherapists from the Oslo Sports Trauma Research Center in the finishing area or during organised meetings at the competitor hotel. We completed a standardised interview form for each athlete, where each athlete was asked to consent to participating in the FIS ISS. If the athlete reported an injury, an injury form was also completed. The injury form consisted of information about the date and place of injury, injury circumstances, body part injured, side (left/right), injury type, injury severity and the specific diagnosis. If an athlete was not present at the event, due to injury or other reason, or if the athlete did not understand English, the team coach, physician or physiotherapist was interviewed. If the athlete was injured at the time of the interview, we used the physician's prognosis to classify the severity of the injury.
Injury Definition
We defined injuries as "all acute injuries that occurred during training or competition and required attention by medical personnel." The injury definition and the classification of body parts and injury types used in the injury form was based on a consensus document on injury surveillance in football. We classified the severity of the injuries, according to the duration of absence from training and competition, as follows: slight (no absence), minimal (1–3 days), mild (4–7 days), moderate (8–28 days) and severe (>28 days).
Exposure Registration
To calculate exposure, we obtained the exact number of started runs by each of the athletes interviewed from the official FIS competition database (http://www.fis-ski.com) for each of the six seasons (2007–2012). The result list for each of the WC races during the six seasons was extracted one by one from the FIS database online into an Excel file. Specific variables were added to the result for each of the athletes, that is, date, discipline, place and sex. In addition, we created a new variable to calculate the number of started runs for each athlete per competition. The exposure data in the Excel file were transferred to our database (Oracle Database 11g, Oracle Corporation, California, USA) where we linked the exposure data for each of the athletes to the information recorded through the interviews. We calculated total exposure, as well as exposure for males versus females and for each of the different snowboarding disciplines.
Statistical Analysis
The injury rate was expressed as the absolute injury rate (injuries per 100 athletes per season) and the relative injury rate (injuries per 1000 runs) with the corresponding 95% CI. When calculating the absolute injury rate we included all recorded injuries, while we only included injuries in official WC, World Snowboard Championship (WSC) and OWG competitions when calculating the relative injury rate, as the number of runs started (exposure) was only available for these events. A total of 15 injuries reported to have occurred in competition could not be attributed to the event reported (HP: n=6, PGS/PSL: n=1, SBX: n=8). We included these in our analysis of the absolute injury rate, as it seems quite likely that these injuries occurred in training prior to the competition rather than in the competition itself. Calculations were based on the Poisson model, and Z tests were used to compare the injury rate and injury pattern between groups. The rate ratio (RR) with 95% CI was computed. A two-tailed p level of <0.05 was considered to be statistically significant.
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