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Original article
Injuries in World Cup telemark skiing: a 5-year cohort study
  1. Melissa Woll Johansen1,
  2. Sophie E Steenstrup1,
  3. Tone Bere1,2,
  4. Roald Bahr1,2,
  5. Lars Nordsletten1,3,4
  1. 1Department of Sports Medicine, Oslo Sport Trauma Research Center, Norwegian School of Sport Sciences, Oslo, Norway
  2. 2Aspetar, Doha, Qatar
  3. 3Orthopaedic Department, Oslo University Hospital, Oslo, Norway
  4. 4University of Oslo, Oslo, Norway
  1. Correspondence to Melissa Woll Johansen, Department of Sports Medicine, Oslo Sports Trauma Research Center, Norwegian School of Sports Sciences, PB 4014 Ullevål Stadion, Oslo 0806, Norway; melissa.w.johansen{at}gmail.com

Abstract

Background There are limited data on injuries in World Cup (WC) telemark skiing.

Objective To describe the injury incidence and injury pattern seen among WC telemark skiers during the competitive season.

Methods We interviewed all WC athletes (or their coach, if the athlete was not present) at the end of five winter seasons from 2008 until 2013. All acute injuries occurring in the competitive season that required the attention of medical personnel were registered. Exposure was calculated based on the official International Ski Federation (FIS) results database.

Results 149 acute injuries were registered during 565 WC skier seasons. The absolute injury incidence was 26.4 injuries per 100 athletes per season (95% CI 22.1 to 30.6), higher for females than males (risk ratio (RR) 1.49, 95% CI 1.07 to 2.08). During the FIS WC competitions, 69 injuries were registered, corresponding to a relative incidence of 8.2 injuries per 1000 runs (95% CI 6.3 to 10.1). The most frequently injured body part was the knee (21%) followed by the hand-finger-thumb (20%), ankle (13%) and shoulder/clavicle (13%). The absolute risk of knee and shoulder/clavicle injuries was higher for females versus males (RR for knee injuries 2.72, 95% CI 1.35 to 5.51; RR for shoulder/clavicle injuries 2.55, 95% CI 1.06 to 6.14). No differences were detected in the injury incidence between disciplines.

Conclusions Female telemark skiers are at 1.5 times greater risk of injury than male skiers. The most commonly injured body part was the knee. The risk of knee and shoulder/clavicle injuries was higher for female athletes than for male athletes.

  • Epidemiology
  • Skiing
  • Injuries
  • Knee
  • Shoulder

https://doi.org/10.1136/bjsports-2014-094211

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    Introduction

    Telemark skiing is a relatively new competitive sport, although the telemark turn and technique have a long history dating back to the 1860s.1 In the early 20th century, the parallel turn and alpine skiing technique became more popular, as new binding constructions attached the heel to the binding. However, the telemark technique managed to hold its position as a landing technique in ski jumping competitions and backcountry skiing, where the free heel made it easier to climb mountains.2

    The International Telemark Committee (ITC) arranged the first World Ski Championship (WSC) in telemark skiing in 1987, and arranged the WSC from 1987 to 1995. Since then, the WSC has been organised by the International Ski Federation (FIS).3 Telemark is not currently an Olympic sport.

    The FIS World Cup (WC) telemark disciplines include telemark classic, telemark sprint and telemark parallel sprint. Telemark giant slalom was removed as a WC event in 2012 and replaced with parallel sprint. The races consist of a telemark section with slalom turns and obstacles, such as jumps and 360° turns, in addition to a cross-country section. Time penalties are given in seconds if a racer has a lack of telemark style while turning, if a racer does not jump as far as the line marked after the jump or fails to land in the telemark position.4 The classic discipline is a one-run race and the average time for the best five senior men should be a minimum of 100 s. The sprint has a two-run format and each run has an average time between 50 and 70 s.4 In the parallel sprint, racers compete side by side down two identical parallel courses. Each round has two runs, with skiers racing once on each side. The winner of the pair continues to the next round.4 A total of 77 WC telemark skiers, including 50 men and 27 women, competed in the FIS WC competitions during the 2012/2013 season.5

    Little is known about the injury incidence and injury pattern among WC telemark racers, but the FIS is committed to address this gap.6 The few studies available in telemark skiing include mainly recreational skiers and recent data are limited.7–17 We aimed to describe the injury incidence and the injury pattern among FIS WC telemark skiers based on data from the FIS Injury Surveillance System (ISS).

    Materials and methods

    Study design and population

    Prior to the 2006–2007 winter season, FIS established the FIS ISS as a continuous injury reporting system for all FIS events.18 Injuries were recorded through the FIS ISS based on retrospective interviews at the end of five WC seasons from 2008 until 2013. Athletes participating in the FIS telemark WC from Austria, Canada, the Czech Republic, Denmark, Finland, France, Germany, Great Britain, Japan, Norway, Slovenia, Spain, Sweden, Switzerland and the USA were interviewed and included in the study. All nations included had a ≥80% response rate to the athlete interviews. All athletes included gave their consent and were registered in the FIS database. Interviews were conducted at the WC finals at the end of each of the five seasons in Bjorli, Norway (March 2009), La Plagne, France (March 2010), Rjukan, Norway (March 2011) and Espot, Spain (2012 and 2013).

    The research teams consisted of physicians or physical therapists from the Oslo Sports Trauma Research Center. All interviews were performed in person in the finishing area or during organised meetings at the competitors’ hotels. A standardised interview form outlining the competition schedule since the start of the season was used and if the athlete reported an injury, a specific injury form was completed.18 Specific injury information from the injury form included the date and place of injury, injury location (expressed as the body part injured), injured side (left/right), injury severity (number of days of absence from full participation in training and competition), injury type, injury circumstance and specific diagnosis. Information on where the injury occurred, if it was during the WC/WSC competitions, official training for these competitions, other competitions, regular training on snow or basic training not on snow was also recorded. If the athlete was not present in person (due to injury or other reasons), interviews were conducted with his/her coach, physician and/or physiotherapist. The coaches were asked to control and correct the list of athletes to confirm that the athletes were official members of the WC team. Athletes who were not defined as being on the WC team were excluded (eg, racers on the national quota). The aim was to register all injuries that occurred between 1 November (start of season) until the season-ending event in March.

    Injury definition

    The FIS ISS defined injuries as “all injuries that occurred during training or competition and required attention by medical personnel.” The injury definition, as well as the classification of the type of injury and body part injured, was based on a consensus document on injury surveillance in football.19 The severity of the injuries was classified according to the estimated duration of absence from training and competition. An injury was classified as slight (no absence), minimal (1–3 days), mild (4–7 days), moderate (8–28 days) or severe (>28 days).19

    Exposure registration

    To calculate exposure, the number of runs started by each athlete per competition for each of the five seasons was counted using the official FIS competition database (http://www.fis-ski.com/). The official results of each of the WC/WSC races during the five seasons were extracted one by one from the FIS online website into an Excel file. Variables such as date, discipline, place, sex and number of started runs were added for each of the athletes. If an athlete did not finish or was disqualified from a run, we included the runs up to, as well as the run where the athlete did not finish or was disqualified. The exposure data in the Excel file were transferred to our database (Oracle database 11g, Oracle Corporation, California, USA), where the exposure data were linked to the information recorded through the interviews. We calculated the total exposure, exposure for males and females and for each of the different telemark disciplines.

    Statistics

    The injury incidence was expressed as the absolute injury incidence (injuries per 100 athletes per season) and the relative injury incidence (injuries per 1000 runs in competition) with their corresponding 95% CIs. All injuries during training and competitions were included when calculating the absolute injury incidence, while injuries occurring in official WC and WSC competitions were included when calculating the relative injury incidence, as the number of runs started (exposure) was available for these events only. Calculations were based on the Poisson model, and Z tests were used to compare injury incidence and injury patterns between groups. The risk ratio (RR) with 95% CI was computed. A two-tailed p level of <0.05 was considered statistically significant.

    Results

    Interviews were conducted covering 565 WC skier seasons throughout five winter seasons (2008–2013). Of these, 293 interviews (52%) were performed with the athletes themselves and 272 (48%) with their coaches or medical personnel. A total of 149 injuries were reported corresponding to an absolute injury incidence of 26.4 injuries per 100 athletes per season (95% CI 22.1 to 30.6; table 1). The absolute injury incidence was higher for women than for men (RR 1.49, 95% CI 1.07 to 2.08; table 1). The majority of injuries occurred during WC/WSC competitions (n=69, 46.3%) or regular training on snow (n=53, 35.6%). The remaining injuries were registered in other competitions (8.1%, n=12), during official training for WC/WSC competitions (6.7%, n=10) or basic training not on snow (2.0%, n=3). In two cases, we did not have information on the circumstances of injury.

    View this table:
    Table 1

    Number of interviews, injuries and runs for males and females during five seasons of International Ski Federation (FIS) World Cup telemark skiing (2008–2013) with corresponding absolute injury rates (injuries per 100 athletes per season) and relative injury rates (injuries per 1000 runs) with their 95% CI

    The relative injury incidence during a total of 8408 runs during WC/WSC competitions was 8.2 injuries per 1000 runs (95% CI 6.3 to 10.1, n=69). No sex difference was detected in the relative injury incidence (table 1). We did not detect any change in absolute or relative injury incidence during the five-season observation period.

    Of all injuries recorded (n=149), 71% were time-loss injuries (n=105). Of these, 31% were severe, that is, with an absence of >28 days (n=32). This corresponds to an absolute injury incidence of 18.6 injuries per 100 athletes per season (95% CI 15.0 to 22.1) for time-loss injuries and 5.7 (95% CI 3.7 to 7.6) for severe injuries. The relative injury incidence for time-loss injuries was 4.8 injuries per 1000 runs (95% CI 3.3 to 6.2, n=40). The knee was the most frequently injured body part, as well with the most severe injuries (table 2).

    View this table:
    Table 2

    Distribution of and relationship between injured body part and injury severity during five seasons of International Ski Federation (FIS) World Cup telemark skiing (2008–2013; n=149)

    The absolute injury incidence for knee injuries was significantly higher for females (10.1 injuries per 100 athletes per season, 95% CI 5.1 to 15.0) than males (3.7 injuries, 95% CI 1.8 to 5.6; RR 2.72, 95% CI 1.35 to 5.51). There was also a significantly higher absolute rate for shoulder/clavicle injuries in females (6.3 injuries per 100 athletes per season, 95% CI 2.4 to 10.2) than among males (2.5 injuries per 100 athletes per season, 95% CI 0.9 to 4.0; RR 2.55, 95% CI 1.06 to 6.14). For the other body parts injured, there were no sex differences.

    For the 69 WC/WSC injuries, we detected no difference in the relative injury risk between disciplines (table 3).

    View this table:
    Table 3

    Competition exposure (runs), number of injuries and relative injury incidence (expressed as the number of injuries per 1000 runs) with 95% CI for all recorded injuries and time-loss injuries (≥1 day absence) for the specific disciplines during five seasons (2008–2013) of International Ski Federation (FIS) World Cup telemark skiing

    Discussion

    This is the first study to examine the injury incidence and injury pattern in WC telemark skiing. The main findings were that the absolute injury incidence (injuries per 100 athletes per season) was 1.5 times higher for female telemark skiers than for male telemark skiers. The knee was the most commonly injured body part, and the absolute injury incidence for knee and shoulder/clavicle injuries was higher for females than for males. There was no difference in the relative injury incidence (injuries per 1000 runs) between the different disciplines.

    Relatively high injury incidence

    We found an absolute injury incidence of 26.4 and a relative injury incidence of 8.2.

    Previous studies in telemark skiing, mainly among recreational skiers, have reported an injury incidence between 0.9 and 10.7 injuries per 1000 skier days.7 ,10 ,11 ,13 ,14 ,20 Comparisons of these results to our findings are difficult because we used a more accurate exposure calculation, as well as a different injury definition and injury registration method. However, the absolute and relative injury incidence has been reported in other FIS disciplines. Our results show that WC telemark skiers are almost at the same risk of injury as WC athletes in alpine skiing, freestyle skiing and snowboarding. However, they are less prone to severe injuries (absence >28 days).21–23 Telemark skiers do not achieve the same speed as alpine skiers because of different elements included in a course and the fact that they ski with a raised heel of the inner ski, which results in less turning energy. The focus on correct technique, where penalties are given for faults, might contribute to lower energy during skiing and less impact in a fall.

    Knee injuries dominant

    The knee was the most commonly injured body part among WC telemark skiers—21% of all injuries. This is similar to WC alpine skiing, freestyle skiing and snowboarding; it extends previous studies in recreational skiing and telemark skiing clubs in North America and Sweden.8 ,11 ,13–15 ,17 Ekeland and Rødven17 studied the injury pattern in Norwegian ski resorts from 1996 to 2008, and reported that as telemark equipment developed the injury pattern began to mimic that of alpine skiing injuries with more injuries to the knee and fewer injuries to the lower leg/ankle. Nevertheless, ankle injuries rank third in telemark skiing, with an injury risk similar to that for shoulder injuries.

    The knee injury mechanisms have been described in alpine skiing.24 ,25 However, owing to the differences in equipment and technique, it is unknown if the same injury mechanisms apply in telemark skiing.

    Female skiers have twice the risk of knee injuries as males

    Female telemark skiers had a higher absolute injury risk than male telemark skiers during the competitive season, especially for knee injuries. This extends several studies suggesting that female skiers have twice the risk of knee injuries compared with male skiers.12 ,16 ,17 ,26–31 A study on anterior cruciate ligament (ACL) injuries among young ski racers in Austria found female athletes to be at greater risk of ACL injury.32 The study provided evidence that poor core strength was a critical factor, irrespective of gender.32 It is also suggested that young female athletes may not be sufficiently prepared for elite ski racing, and may therefore be at higher risk of injury.33 Ekeland and Rødven17 reported that knee injuries were related to skiing ability, and that the population of injured recreational female skiers had lower ability than that of injured males on Norwegian slopes. It is not known if these explanations apply to our findings.

    In contrast, Bere et al33 reported no sex difference in knee injury risk among WC alpine skiers. The high energy involved was suggested to cancel out potential sex-related intrinsic risk factors. Anatomical and physiological differences between women and men in WC alpine skiing would therefore have less influence on the risk of knee/ACL injuries. The energy in WC telemark skiing is probably not as high as that in WC alpine skiing. It is also important to note that female and male WC telemark skiers compete in the same course, unlike WC alpine skiers who have different courses for males and females. In telemark skiing, the skiers are therefore influenced by the same extrinsic factors (course length, height of vertical drop, jump, 360), except the length of the jumping zone, which is usually shorter for women than for men.34

    This is the first study to report a higher risk of shoulder injuries among female skiers than male skiers, which is in contrast to previous studies in recreational skiing.12 ,14 ,17 More cautious skiing was suggested as an explanation for why female skiers and snowboarders had a lower risk of upper limb injuries.12 Upper limb and head injuries were often associated with falling from a jump.12 Recreational skiing males might jump more in the backcountry or in the slope than females, while in the WC females and males compete on the same course with the same elements. However, as the jumping zones are different, with males jumping farther, there might be more energy involved in male jumps. It is difficult to say whether this relates to our results, as we do not have data on how or under which circumstances the skiers were injured. Further research into the injury situations and injury mechanisms in WC telemark skiing using video analysis would help us clarify the circumstances of injury.

    We did not detect any significant difference in relative injury risk between sexes, most likely because the number of injuries in competition is limited. When doing subanalyses of the data, the statistical power is very low.

    No difference in injury incidence between telemark disciplines

    We did not find any significant difference in the relative or absolute injury incidence between the different disciplines in WC telemark skiing. Looking at the incidence for each discipline, the number of injuries was limited when assessing subgroups. It should be kept in mind that the data from parallel sprint are from two seasons only, and the results should be interpreted with caution because of the low study power.

    Methodological considerations

    Recall bias is a challenge when using retrospective interviews as a method for recording injuries. In this study, all injury recording during the five WC seasons was through interviews with athletes, medical personnel or coaches. A methodological study found that retrospective interviews gave the most complete picture of injuries to WC skiers and snowboarders compared with prospective injury recording by team medical personnel or FIS technical delegates.18 A critical strength of our approach was that all interviews were performed at the end of each season and interview forms based on race schedules were used to help the interviewee remember incidents during the season. Despite this, owing to the recall bias, we cannot guarantee that all injuries have been reported, especially slight or minor injuries not causing substantial time loss. Also, as some teams travel without medical personnel, this might have influenced their decision to seek medical attention for minor injuries or not. In addition, injury severity was reported at the time of the interview, so our injury severity classification may underestimate (or overestimate) the true severity for those who are injured at the end of the season and have yet to be medically cleared.

    Telemark athletes should focus preventive training towards knee injuries based on the injury pattern observed. Whether this proves effective will need to be tested, but systematic review data from other sports are encouraging.35

    Whether women and men should compete in different courses should be evaluated. Continuing injury surveillance for more consecutive seasons would strengthen the data and could give a clearer picture of any sex differences in injury incidence. Strong data over a larger amount of seasons showing that females have an increased risk of injury could provide a basis for discussions around the safety of males and females competing on the same courses. Subsequently, competing on different courses could be one of the safety measures to explore.

    Future studies should attempt to identify injury situations and injury mechanisms in WC telemark skiing by obtaining videos of telemark skiing injuries to describe the mechanisms involved.

    In summary, female telemark skiers were at 1.5 times the risk of male telemark skiers for sustaining an injury during the competitive winter season, especially knee and shoulder injuries.

    What are the new findings?

    • In the first cohort study examining the injury incidence and injury pattern in World Cup telemark skiing, injury risk is high compared with the other International Ski Federation (FIS) disciplines of alpine skiing, snowboarding and freestyle skiing.

    • The knee was the most commonly injured body part, and almost half of these injuries were severe.

    • The injury risk was higher in females than in males, especially for knee and shoulder/clavicle injuries.

    How might it impact on clinical practice in the near future?

    • Prevention strategies in World Cup telemark skiing should focus on knee injuries and severe injuries.

    • Particular attention should be paid to injury prevention among female telemark skiers.

    • Continued research into injury situations and injury mechanisms is needed. This can be achieved by analysing videos of injury situations.

    Acknowledgments

    The authors thank the International Ski Federation staff and officials for all practical support in collecting injury data, as well as the athletes, coaches and medical staff who participated in this study. The authors would also like to thank Tonje Wåle Flørenes, MD, PhD, who was responsible for establishing the International Ski Federation Injury Surveillance System (FIS ISS).

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    Footnotes

    • Contributors MWJ, SES, TB, RB and LN contributed to the study conception, design and methodology. MWJ, SES and TB coordinated the study and managed the data collection. MWJ wrote the first draft of the paper, and all authors contributed to the final manuscript. MWJ and LN are guarantors.

    • Funding The Oslo Sport Trauma Research Center has been established at the Norwegian School of Sport Sciences through generous grants from the Royal Norwegian Ministry of Culture, the South-Eastern Norway Regional Health Authority, the IOC, the Norwegian Olympic Committee & Confederation of Sport and Norsk Tipping AS. The FIS Injury Surveillance System is supported by the International Ski Federation and was established through a grant from Don Joy Orthotics (DJO).

    • Competing interests None.

    • Ethics approval The project has been reviewed by the Regional Committee for Medical Research Ethics, South Eastern Norway Regional Health Authority, Norway and approved by the Social Science Data Services.

    • Provenance and peer review Not commissioned; externally peer reviewed.