Discussion

Most terrain park injuries resulted from high falls among non-beginner male snowboarders aged 13–24 years, and were more likely to involve severe injury requiring hospital transport compared to injuries on slopes. Snowboarding injuries are common among young men.6–9 There were more injuries among self-rated intermediates and experts than beginners.6 10 Beginners may appropriately assess their low skill level and not attempt manoeuvres beyond their ability. Injured intermediates/experts may overestimate their true ability and be misclassified beginners.

Hagel hypothesised that beginner child snowboarders from the 1990s may now be experienced adolescent snowboarders attempting difficult tricks in terrain parks.6 Advanced skill implies faster speeds and attempts at higher, more difficult jumps. If aerial manoeuvres attempted are not in proportion to ability level, more severe injuries may occur. The sport of snowboarding and terrain park design allow for extreme tricks and high risk-taking attitudes.11 Some terrain park features are not designed for aerial manoeuvres, and traditional slopes may include terrain-like cliffs or moguls for aerial manoeuvres.

Helmet use is more prevalent among experts, children and snowboarders12–14; a higher proportion of those injured in terrain parks were wearing helmets, perhaps reflecting a younger, expert, snowboarder population. Terrain park injuries were more likely to be concussion or involve the head; however the majority of those injured in terrain parks were not wearing a helmet. There is convincing evidence that ski helmets reduce risk of head injury.4 15–17 Traumatic brain injury remains the leading cause of death and morbidity for both skiers and snowboarders.7 18–20 At national snowboarding events, head injuries only occurred in freestyle events (half-pipe and big air).11 Helmets are not mandatory at most US ski areas but perhaps should be mandatory in terrain parks.

Many terrain park features are designed for jumps and aerial manoeuvres. Terrain park injuries were from high falls and more likely to involve back injury. Snowboarders landing from a jump are more likely to fall backwards and sustain axial skeleton injury.3 Spine injuries are increasing, particularly among snowboarders, and as previously suggested, the advent of terrain parks and increased snowboarding popularity may explain this increase.1 9 21–23

Goulet et al reported that snow-park injuries were more likely to be severe and require ambulance evacuation than slope injuries; severe injuries were defined as fractures, internal injury to head, chest or abdomen, and concussion.2 The current study also reports a higher likelihood of severe injury and need for hospital transport in terrain parks versus slopes. Goulet et al found that snowboarders only had a higher risk of severe extremity injuries in snow-parks compared to slopes. In contrast this study found that severe snowboarding injuries in terrain parks were more likely to involve head and back, not extremities. Both studies suggest that it is primarily the nature and design of terrain parks that leads to severe injury, although activity type likely contributes. Evidence exists that snowboarding may inherently be more dangerous than skiing, and it has now been shown that terrain parks may be more dangerous than slopes.6 24 Terrain parks attract many snowboarders, and evidence suggests that an injury problem has arisen from this combination.

Terrain parks contain metal features like rails and boxes to slide along, and striking a body part on the feature may result in injury.25 Chest/abdomen injuries were almost twice as likely in snowboarders than in skiers injured in terrain parks. The fixed leg position restricts lower body movement and may predispose to trunk or upper body movement that leads to injury.11 The triad of male gender, aerial manoeuvres (jumping) and abdominal trauma, specifically splenic injury, has been labelled ‘boarder belly’ or ‘snowboard spleen’.26 27

Exposure data for time spent or runs completed in terrain parks compared to slopes was not available; rates of injury in terrain parks versus slopes could not be calculated. Ski patrol injury report forms did not distinguish between different self-rated ability based on terrain. Only injuries reported to and which received treatment from ski patrols were analysed. Injuries bypassing ski patrols and seen directly by another healthcare provider, and follow-up information on treatment and outcome of injuries requiring hospital transportation were not available for analysis. Ski patrol assessment is assumed to be correct. Moderate to almost perfect agreement has been shown between ski patrol injury reports and self-reported follow-up information.28 Misclassification of data on ski patrol injury reports is possible, but such misclassification would likely occur similarly to those injured in terrain parks and on traditional slopes.

This study's findings suggest an injury problem related to types of activities and manoeuvres performed in terrain parks. Future research could identify injury risk factors for each terrain park feature. Injury programmes might target at-risk populations which use terrain parks and ski areas which contain them. Detailed examination of injury events in terrain parks could lead to design changes that decrease injury; for example, less difficult features for beginners, and marking the difficulty of terrain park features with the same ratings as traditional slopes.29 Formal instruction targeting young male snowboarders and focusing on technical jumping and landing skills may reduce injury.25 Lessons could be mandatory before access to difficult terrain parks is granted.