Occurrence and trends in ski injuries in Norway

OBJECTIVES: To provide an overview of ski injuries in Norway and to describe the changes between 1990 and 1996. METHODS: All ski injuries (7966) treated at four hospitals providing health care to a defined population of about 11% of the Norwegian population were registered prospectively from 1990 to 1996. For this study, 6462 injuries sustained in cross country skiing, downhill skiing, telemark skiing, and snowboarding were selected for further analysis. RESULTS: The relative distribution of ski injuries by type of skiing changed significantly from 1990 to 1996 (p<0.001). Injuries from snowboarding showed the highest relative increase, and those sustained during downhill skiing showed a decline. The proportion of fractures in all types of skiing increased during the study period (p=0.001). The proportion of injuries to knee/lower leg decreased and the proportion to the forearm/wrist/hand increased during the study period (p=0.03). The mean age of the injured skiers differed significantly among the different types of skiing activity (p<0.001): cross country skiers were the oldest followed by telemark skiers, downhill skiers, and snowboarders. CONCLUSIONS: Ski injury surveillance results in early detection of changes in temporal injury trends, allowing timely adjustment of injury prevention strategies. Injuries from snowboarding are on the increase in Norway, warranting more effective injury prevention measures.


     

Downhill skiing injuries and their cost at a Finnish skiing area

During the 1987–1990 ski seasons. 325 consecutive patients sustained downhill skiing injuries at a skiing area in central Finland. The calculated injury rate was 0.94 per 1000 skier-days (0.9%) and 0.56 per 1000 skiers (0.06%). Forty-one percent of the injuries were located in the lower limbs and 37% in the upper limbs. Sprain was the most common type of injury (34%), followed by fractures (22%) and contusions (17%). Only 7% of the patients needed surgery. The estimated mean cost of medical treatment and sick leave was FIM 5500 (USD 1400) per patient.     

Injury risk factors among telemark skiers

We performed a population survey of telemark skiers over two ski seasons to determine specific risk factors for injury. The survey inquired about the skier's sex, experience, equipment used, injuries, and number of days skied in each season. The respondents completed the surveys whether or not they were injured while skiing. We received 677 responses from telemark skiing clubs, with 19,962 skier-days of data. The number of self-reported injuries was 178, for an overall self-reported injury rate of 8.9 per 1000 skier-days. Knee injuries (N = 48) were the most common injury (27%), followed by thumb (N = 32, 18%) and shoulder (N = 21, 12%) injuries. Specific risk factors for injury were identified with multivariate regression and survival analysis. The skill level of the skier had a significant injury-sparing effect, as did the use of plastic telemark boots. The protective effect of the plastic boots was likely due to the increased stability they provided compared with traditional leather boots. There were fewer knee injuries with the recently available releasable bindings for telemark skis. Sex and age had no significant impact on injury rates in this study population. As all reported deaths associated with telemark sking were due to environmental hazards, skiers must continue to pay close attention to these hazards in the backcountry.     

Alpine ski injuries and their prevention

Alpine skiing is a popular sport with significant risk of injury. Since the 1970s, injury rates have dropped from approximately 5 to 8 per 1000 skier-days to about 2 to 3 per 1000 skier-days. The nature of the injuries has also been transformed over the same period. Lower leg injuries are becoming less common while the incidence of knee sprains and upper extremity injuries is becoming more common. Much of this change can be attributed to advancements in binding technology, which effectively reduces lower leg injury, but does not adequately address the issue of knee sprains. Along with design, binding adjustment and maintenance are important preventative factors. Poorly adjusted bindings have been correlated with increased injury rates. Upper extremity injuries constitute approximately one-third of skiing injuries, with ulnar collateral ligament sprains and shoulder injuries being the most common. Strategies to prevent these include proper poling technique and avoidance of non-detachable ski pole retention devices. Spinal injuries in skiers have been traditionally much less common than in snowboarders, but this disparity is likely to diminish with the recent trend of incorporating snowboarding moves into skiing. Strategies to help reduce these injuries include promoting the development of terrain parks and focussing on proper technique during such moves. Head injuries have been increasing in incidence over recent decades and account for more than half of skiing-related deaths. The issue of ski helmets remains controversial while evidence for their efficacy remains under debate. There is no evidence to demonstrate that traditional ski instruction reduces injury frequency. More specific programmes focussed on injury prevention techniques are effective. The question of pre-season conditioning to prevent injuries needs further research to demonstrate efficacy.     

Cross-country skiing injuries and biomechanics

Cross-country skiing exercises most of the joints, muscles and tendons in the body giving the skier an all around workout. This, in combination with a low incidence of injury, makes cross-country skiing an ideal recreational and competitive sport. The new skating techniques developed during the last decade have resulted in greater velocity. The maximum speed during the diagonal stride technique is 6 m/sec compared to 8 to 9 m/sec when skating and double poling. Top-level skiers today use strong and ultra light skis of fiberglass and graphite. The ski weight is less than 500g. Today's skating technique does not require any waxing and only the cambered portion of the ski is waxed when performing the diagonal stride. The preparation of the ski course has improved with the development of special track machines. This allows top-level skiers to reach 60 to 80 km/h on downhill slopes, which has resulted in an increased risk of injury. Because cross-country skiing takes place wherever snow is available, it is difficult to establish accurate injury rates in comparison to alpine skiing which is performed on very specialised terrain at ski areas. Studies estimate the cross-country ski injury rate in Sweden to be around 0.2 to 0.5 per thousand skier days. A prospective study of cross-country ski injuries conducted in Vermont revealed an injury rate of 0.72 per thousand skier days. 75% of the injuries sustained by members of the Swedish national cross-country ski team during 1983 and 1984 were overuse injuries while 25% resulted from trauma. The most common overuse injuries included medial-tibial stress syndrome, Achilles tendon problems and lower back pain. Most common among traumatic injuries were ankle ligament sprains and fractures, muscle ruptures, and knee ligament sprains. Shoulder dislocation, acromioclavicular separation and rotator cuff tears are not infrequent in cross-country skiing. Injuries to the ulnar collateral ligament of the metacarpal phalangeal joint of the thumb (Stener's lesion) is the most common ski injury involving the upper extremity. Cross-country skiers 16 to 21 years of age complained more frequently of mild lower back pain than similarly aged non-skiers. This may result from repetitive hyperextension motions during the kick phase and the recurring spinal flexion and extension during the double poling phase. Repeated slipping on hard and icy tracks infrequently produce partial tears or microtrauma in the muscle tendinous units of the groin.(ABSTRACT TRUNCATED AT 400 WORDS)     

Are self‐reported risk‐taking behavior and helmet use associated with injury causes among skiers and snowboarders?

Over the last 10 years, ski helmet use has steadily increased worldwide. According to the “risk compensation theory,” however, studies found that up to one third of skiers and snowboarders self‐reported to engage in more risk taking when wearing a ski helmet. Therefore, to evaluate whether self‐reported risk taking and ski helmet use affect accident causes on ski slopes, more than 2000 injured skiers and snowboarders were interviewed during the 2011/2012 winter season about accident causes and potential intrinsic and extrinsic risk factors. Chi‐square tests revealed that ski helmet use did not significantly differ between self‐reported risky and cautious people (81% vs 83%). Multivariate regression analysis revealed younger age groups [odds ratios (ORs) 1.8–1.9, P < 005], male sex (OR 2.4, P < 0.001), Austrian nationality (2.2, P < 0.001), higher skill level (1.7, P < 0.001), and off‐slope skiing (OR 2.2, P = 0.060) to be predictive for a risky behavior on ski slopes. Neither the use of skis or snowboards nor accident causes were significantly associated with a riskier behavior on ski slopes. In conclusion, self‐reported risk‐taking behavior and ski helmet use seem not to be associated with accident causes leading to an injury among recreational skiers and snowboarders.     

Skiing safety in children: a prospective study of downhill skiing injuries and their relation to the skier and his equipment

A prospective analysis was made of 31 children who sustained an injury of the lower extremity during downhill skiing. They were compared with a control population of 183 skiers. The injured children were to a large extent less skillful skiers and tended to be injured at the start of their skiing season. In general, the risk of having an injury did not seem to be influenced by the question of where or by whom the bindings were adjusted. Nevertheless, beginners predominantly had had their bindings adjusted in ski shops. The heel mechanism functioned well in most cases, while the function of the toe mechanism was poor in the control population and even poorer in the injury group. The results indicate that many of the present release bindings used by children are of poor quality and should be improved. At present, a reasonable recommendation for children should be to set the heel mechanism according to the standard scale and the toe mechanism as loosely as possible without having a release during ordinary skiing. Increased use of testing devices is advocated. In Sweden, improved education of personnel in ski shops, with the children in focus, seems important, and training and supervision of the beginners should be intensified.     

Distribution of injury mechanisms and related factors in ACL-injured female carving skiers

While ACL injury mechanisms in skiers using traditional skis are well studied, no study has yet investigated the distribution of injury mechanisms in carving skiers. In traditional skiers, the backward twisting fall seems to be the dominant injury mechanism, especially in female skiers. Female recreational skiers have a threefold higher risk to sustain an ACL injury than male skiers; therefore, it is important to determine if carving skis influence the distribution of injury mechanisms and the related frequencies of ACL injuries in female skiers. We investigated the frequencies of injury mechanisms and related factors in 65 ACL-injured female carving skiers by questionnaire. The forward twisting fall was the most reported ACL injury mechanism with about 51%, followed by the backward twisting fall within 29% of cases. Catching an edge of the ski (59 vs. 24%, P = 0.03) when executing turns (69 vs. 41%, P = 0.053) was a more frequent cause for forward twisting falls than for the other types of falling. While 29% of bindings released during a forward twisting fall, only 3.1% released during the remaining mechanisms. In contrast to traditional skiers, the forward twisting fall was the dominant injury mechanism in female carving skiers with ACL injury.     

Physiology of Alpine skiing

Physiological profiles of elite Alpine skiers reveal the importance of muscular strength, anaerobic power, anaerobic endurance, aerobic endurance, coordination, agility, balance, and flexibility. On-hill snow training and dryland training programmes should focus on the elevation of these fitness components. Physical characteristics of elite skiers reveal an average height and body mass. Today, successful skiers are taller and heavier than their predecessors. Slalom skiers tend to be leaner than skiers in other events while the downhill racers are the heaviest. Elite skiers have strong legs when peak torque is measured during isometric and isokinetic conditions involving knee extension, which may be a specific adaptation since the skier is in a crouched position for a prolonged period when racing. Leg strength correlates significantly with performance in the downhill and giant slalom events. The glycolytic contribution in the slalom and giant slalom events is about 40% of the total energy cost. Following a race, blood lactate concentration averages 9 to 13 mmol/L. A muscle lactate concentration of 24 mmol/kg wet muscle tissue has been reported. Elite skiers have higher lactate values than advanced or novice skiers. The aerobic demands of competitive Alpine skiing may approach (90 to 95%) of the athlete's maximal aerobic power. Maximal heart rate is achieved during the latter part of the race. Elite skiers have a high VO2max. This may reflect their training programme and not the actual demands of the sport. When turning, muscular activity acts to impede blood flow and oxygen delivery. As a consequence, anaerobic metabolism is increased. Glycogen studies show significant utilisation from both slow and fast twitch muscle fibres. Skilled and unskilled skiers differ with respect to glycogen utilisation. Skilled skiers have greater glycogen depletion in the slow twitch fibres compared to unskilled skiers. Muscle glycogen decreases by about 32 mmol/kg wet muscle tissue following a day of ski training. Glycogen depletion may contribute to the injury pattern which peaks toward the end of the ski day. The risk of injury has been estimated at 17 injuries per 1000 skier days. When the severity criterion was an injury causing the skier to miss 3 days of skiing or visit a physician, the risk was 2 injuries per 1000 skier-days.(ABSTRACT TRUNCATED AT 400 WORDS)     

Type of sport is related to injury profile: A study on cross country skiers,swimmers, long‐distance runners and soccer players. A retrospective 12‐month study

This 12‐month retrospective questionnaire compared the occurrence of sports injuries in 149 cross country skiers, 154 swimmers, 143 long‐distance runners and 128 soccer players aged 15–35 years. Soccer had significantly more injuries (5.1 injuries/1000 exposure hour) than other sports (2.1–2.8, P<0.001). More runners than soccer players reported overuse injuries (59% vs 42%, P=0.005), locating typically in the foot in runners, soccer players and skiers. Swimmers reported overuse injuries in the shoulder more commonly than skiers (40% vs 1%, P<0.001), who also intensively load shoulders. Acute injuries in skiers (80%) and in swimmers (58%), and overuse injuries in skiers (61%), occurred during exercise other than own event. In soccer and running the absence time from sport because of injuries was significantly longer than in skiing and swimming. No severe permanent disabilities occurred due to injury but seven women quit sports because of injury. In conclusion, type of loading is strictly associated with the anatomical location of an overuse injury as shown by the difference in shoulder injury incidence between swimmers and cross country skiers. In some sports, a significant proportion of acute injuries occur in other than the main event.     

Mechanisms of anterior cruciate ligament ruptures in skiing

In the years 1980–1989, 78 patients with an acute anterior cruciate ligament (ACL) rupture sustained during downhill or cross-country skiing were treated at the University Hospital of Tampere, Finland. In every case, the ACL rupture was verified at arthroscopy or open surgery. The injury mechanism could be clarified for 51 patients using a collection of pictures of the most typical injury mechanisms in skiing. Thirty-nine of them (76%) were women and 12 men (24%). In 32 cases (63%) the injury occurred during downhill skiing and in 19 cases (37%) during cross-country skiing. In 24 cases (47%) the injury mechanism was valgus-external rotation, in 21 cases (41%) flexion-internal rotation, in two cases hyperextension-internal rotation, while in four cases the exact mechanism remained unclear. The great majority of the patients with an injury mechanism of flexion-internal rotation were women (90%), and they were significantly older than the patients with an injury mechanism of valgus-external rotation (mean ages 44 and 34 years, respectively:P<0.05). According to the patients' subjective evaluation, the main reasons for the injury were poor ski area conditions (such als slippery slopes and trails) and deficient equipment, especially poorly functioning bindings. Many of them had had little skiing experience before the accident.     

Parameters of injury reporting in skiing

An injury survey of 505 skiers from the 1971-72 and 5,459 skiers from thh 1972-73 season collected 601 time loss injries for a rate of 9.31000 skier days. Forty percent of these injuries were reported to a ski patrol and almost 60 to physicians. Fractures and lacerations were reported to the patrol more frequently than other injury types, bruises and strains less commonly. Injuries not reported to patrols and physicians were primarily bruises, sprains and strains. Although fractures were almost invariably reported to physicians, one in four was not seen by the ski patrol. Patrol-only or physician only reported injuries thus do not represent the full spectrum of time loss skiing injuries.     

Risk factors associated with alpine skiing injuries in children. A case-control study.

We investigated the relative contribution of four risk factors to the occurrence of injuries among alpine skiers aged 12 years and younger (3 to 12 years old; mean age, 9.43 years). The risk factors selected were deficient binding adjustment, absence of formal training, low skill level, and use of rented equipment. A group of injured skiers (N = 41) and a control group of uninjured skiers (N = 313) were recruited among young skiers at one major alpine ski center in the Quebec City, Canada, area during the 1995 to 1996 season. No significant group differences were found for mean age or sex distribution. The adjusted odds ratios for injury were 7.54 (95% confidence interval [2.57, 22.15]) for skiers in the low level of skill category relative to highly skilled skiers, 7.14 (2.59, 19.87) for skiers who rented their ski equipment compared with skiers who owned their equipment, and 2.11 (1.02, 4.33) for skiers with ill-adjusted bindings compared with skiers with better-adjusted bindings. Only formal training did not meet the 0.05 significance level for entry into the model; this is probably because of methodologic limitations. Implications of these results for the development of a prevention program aimed at young skiers are discussed.     

A systematic video analysis of 69 injury cases in World Cup alpine skiing

We have limited insight into how injuries occur in professional ski racing. The aim of this study was to describe the injury situations in World Cup alpine skiing. Injuries reported through the International Ski Federation Injury Surveillance System for three consecutive World Cup seasons (2006–2009) were obtained on video. In total, 69 injuries and 124 runs of matched controls were analysed by five experts to evaluate the skiing situation, skier behavior, as well as piste‐related factors. A chi‐square test (95% CI, P ≤ 0.05) was used to examine whether there was a difference between course sections regarding where the injury situation occurred. The skier was most frequently turning (n = 55) or landing from a jump (n = 13) at the time of injury. Most of the injuries to the head and upper body (96%) resulted from crashes, while the majority of knee injuries (83%) occurred while the skier was still skiing. Gate contact contributed to 30% of the injuries, while 9% occurred at contact with safety nets/material. Almost half of the injuries (46%) occurred in the final fourth of the course. A particular concern was the high contribution of inappropriate gate contact and the high‐energy impacts to the body when crashing.     

Injury patterns in nordic ski jumpers. A retrospective analysis of injuries occurring at the Intervale Ski Jump Complex from 1980 to 1985

No studies describing the types and frequencies of nordic ski jumping injuries have been reported in the medical literature. We examined records of injuries sustained at the Intervale Ski Jump Complex (15, 40, 70, and 90 meter jumps) in Lake Placid from 1980 to 1985. Forty-seven injured jumpers sustained 72 total injuries. The most frequent injuries were contusions. Fractures occurred in 11 jumpers; most were nondisplaced. Upper extremity fractures outnumbered lower extremity fractures. Injuries requiring hospitalization were uncommon; none of these resulted in permanent disability. Injury rates for non-World Cup and for World Cup competitions were 4.3 and 1.2 injuries per 1,000 skier-days, respectively. This is roughly equivalent to injury rates in alpine skiing. Our study suggests that the dangers of nordic ski jumping have been overestimated.     

Epidemiology of alpine skiing injuries in lowlanders

During one alpine skiing season injuries were registered prospectively among 951 Danish alpine skiers. The injury incidence was 19.4 injuries per 1000 skiing days, or 3.4 injuries per 1000 skiing hours. The incidence of injuries treated by a doctor was 5.9 injuries per 1000 skiing days, which is 2–5 times higher than previously reported. Lower extremity doctor-treated injuries comprised 65% of the total and upper extremity doctor-treated injuries 25% - a distribution seen 25 years ago in alpine skiing countries. Only 18% of the thumb injuries were seen by a doctor. Neither age, preholiday training, self-rated skiing ability, ski school attendance during the week nor the use of rented versus owned equipment significantly influenced the risk of injury.     

Impact of environmental factors on knee injuries in male and female recreational skiers

In alpine skiing, the knee represents the dominant injury location with marked gender differences. Snow, slope and weather conditions as well as altitude and low temperatures are thought to influence the prevalence of knee injuries. Therefore, ski patrol injury reports were used to compare gender-specific prevalence of knee injuries with regard to several environmental factors including the actual air temperatures. A total of 1039 non-contact knee injuries were reported with a corresponding prevalence of knee injuries of 44.4% (males: 30.1%; females: 57.4%). Temperature quartiles of all recorded injuries were calculated to compare gender-specific prevalence of knee injury with regard to temperatures. Comparing the first quartile (mean temperature -11°C) with the fourth quartile (mean temperature +3°C), the prevalence of knee injury in female skiers was higher at low ambient temperatures (61% vs 50%, odds ratio: 1.60, 95% confidence interval: 1.16-2.22; P=0.005) while no such association was found for male skiers. Additionally, knee-injured females showed a twofold prevalence when skiing during snowfall compared with females with other injuries (15.4% vs 8.6%; P=0.001). No other environmental factor showed a significant association with the gender-specific prevalence of knee injury. In conclusion, low ambient temperature and snowfall are important environmental risk factors for knee injuries in female skiers.     

Anterior cruciate ligament injury incidence among male and female professional alpine skiers

A retrospective review of anterior cruciate ligament injuries among professional alpine skiers was performed to compare sex-related differences in injury incidence. We screened 7155 ski patrollers or instructors (4537 men and 2618 women) for knee injuries before each ski season between 1991 and 1997. Screening involved a ski history questionnaire, a knee injury history questionnaire, and a knee physical examination. Any patient with an equivocal Lachman or pivot shift test was evaluated by KT-1000 arthrometry and excluded from the study if the manual maximum side-to-side difference was 3 mm or more. Thus, the study population was limited to subjects with intact anterior cruciate ligaments. Skiers injured during the study were identified through mandatory workers' compensation claims. Each injured skier was reevaluated using an injury questionnaire and physical examination. The men skied an average of 110 days per year (499,070 skier-days) and the women skied an average of 87 days per year (227,766 skier-days). Thirty-one skiing-related anterior cruciate ligament injuries were diagnosed, 21 in men and 10 in women. The incidence of ACL disruption was 4.2 injuries per 100,000 skier-days in men and 4.4 injuries per 100,000 skier-days in women. These data suggest that the incidences of anterior cruciate ligament injuries among male and female professional alpine skiers are similar.     

Spinal injuries in skiers and snowboarders

Spinal injuries are among the most devastating injuries associated with recreational sports. Snowboarding spinal injury patterns have not been described. During two seasons (1994 to 1995 and 1995 to 1996), 34 skiers and 22 snowboarders suffered serious spinal injuries (fracture or neurologic deficit or both) at two ski areas in British Columbia, Canada. Ski patrol records, the Provincial Trauma Database, and hospital records were reviewed. Injury rates were based on computerized lift-ticket data and a population estimate of 15% snowboarders (ski patrol observation). The incidence of spinal injury among skiers was 0.01 per 1000 skier-days, and among snowboarders was 0.04 per 1000 snowboarder-days. Mean age was 34.5 years for skiers and 22.4 years for snowboarders. Seventy percent of the skiers were men, whereas all of the snowboarders were men. Jumping (intentional jump > 2 meters) was the cause of injury in 20% of skiers and 77% of snowboarders. Neither age nor sex accounted for any significant portion of this difference. The rate of spinal injuries among snowboarders is fourfold that among skiers. Although jumping is the primary cause of injury, it is an intrinsic element of snowboarding. Until research defines effective injury-prevention strategies, knowledge of the risk of snowboarding should be disseminated and techniques for safe jumping should be taught.     

Prior myocardial infarction is the major risk factor associated with sudden cardiac death during downhill skiing

More than 90% of all sudden cardiac deaths (SCDs) during downhill skiing, the most popular winter sport world-wide, are attributed to men over the age of 34. However, no data exist on additional risk factors and triggers for SCD related to downhill skiing. Therefore risk factor profiles of 68 males who died from SCD during downhill skiing were compared to those of 204 matched controls. Skiers who suffered SCD had much more frequently prior myocardial infarction (MI) (41% vs. 1.5%; p<0.001), hypertension (50% vs. 17%; p<0.001), known coronary heart disease (CHD) without prior MI (9% vs. 3%; p=0.05) and were less engaged in strenuous exercise (4% vs. 15%; p<0.05) when compared to controls. Multivariate analyses even enhanced the importance of these risk factors. Downhill skiing is considered to be a serious trigger for SCD especially in skiers with prior MI but also for those with hypertension, known CHD without prior MI, or insufficient adaptation to strenuous exercise. Skiing-related increased sympathetic activity might well disturb the autonomic balance with subsequent arrhythmias and/or may increase cardiac work and platelet aggregability with possible plaque rupture and coronary thrombosis. Therefore adaptation to high intensity exercise and therapeutic interventions or abstinence from skiing in certain cases should be considered for downhill skiers at high risk.