See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/257778802 Designing tomorrow’s snow park jump Article in Sports Engineering · March 2012 DOI: 10.1007/s12283-012-0083-x CITATIONS READS 21 310 3 authors, including: James Mcneil Mont Hubbard Colorado School of Mines University of California, Davis 55 PUBLICATIONS 1,282 CITATIONS 171 PUBLICATIONS 2,194 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Ski jump safety View project Terrain park jump safety View project All content following this page was uploaded by Mont Hubbard on 04 June 2014. The user has requested enhancement of the downloaded file. Sports Eng (2012) 15:1–20 DOI 10.1007/s12283-012-0083-x ORIGINAL ARTICLE Designing tomorrow’s snow park jump James A. McNeil • Mont Hubbard • Andrew D. Swedberg Published online: 31 January 2012 Ó International Sports Engineering Association 2012 Abstract Recent epidemiological studies of injuries at parity with skiers [1]. Based on data from the National ski resorts have found that snow park jumps pose a sig- Sporting Goods Association, of 11.2 million snow-slope nificantly greater risk for certain classes of injury to resort participants in 2008, 5.3M skied only, 4.7M snowboarded patrons than other normal skiing activities. Today, most only, and 1.2M did both. Because the snowboarding recreational jumps are built by skilled groomers without an population is younger and demands more access to the engineering design process, but the Snow Skiing Com- acrobatic aspects of sliding than previously, ski resorts mittee (F-27) of the American Society for Testing and instituted and continue to experiment with snow terrain Materials is considering the inclusion of recreational jumps parks which include jumps and other airborne features. in their purview which may lead to a greater role for Epidemiological studies of injuries at ski resorts have engineering jump designs in the US in the future. Similar found that snow park jumps pose a significantly greater risk efforts are underway in Europe as well. The purpose of this for certain classes of injury to resort patrons than other work is to review the current state of the science of snow skiing activities [2–5]. In particular, due to increases in park jumps, describe the jump design process, and outline flight maneuvers and associated landings, a corresponding the role that modelling will play in designing tomorrow’s increase in the frequency and severity of head, neck and snow park jumps. upper-extremity injuries has been documented [2]. In a report widely publicized by the National Ski Areas Association (NSAA), Shealy et al. [6] noted that over the 1 Introduction period from 1990 to the present when overall snow terrain park use has risen, overall injury rates have actually fallen. The last two decades have witnessed a dramatic evolution Yet, all studies that focus on actual terrain park injuries in the skiing industry worldwide. The number of partici- show that terrain parks do indeed present a special hazard pants on snowboards has increased and now approaches to riders. The Shealy finding is most likely due to improved ski equipment and an aging, and therefore more cautious, demographic patron profile over the period & J. A. McNeil ( ) covered in his study. Early research recognized that Department of Physics, Colorado School of Mines, Golden, CO 80401, USA snowboard injury patterns differed from those of skiers e-mail: [email protected] [7], and that snowboard injury rates could be as much as six times higher than those of skiers [8]. The snowboard M. Hubbard injury rate was discovered to have doubled between 1990 Department of Mechanical and Aerospace Engineering, University of California, Davis, CA 95616, USA and 2000 from 3.37 to 6.97 per 1,000 participant days [9]. e-mail: [email protected] In addition, jumping was found early to be the most important cause of injury [8]. An increased risk of head A. D. Swedberg injury at terrain parks as compared to ski runs continued Department of Mathematics, U.S. Military Academy, West Point, NY 10996, USA through the end of the last decade [10]. A recent study of e-mail: [email protected] snowboard injury rates specifically in terrain parks found 2 J. A. McNeil et al. that the risk of injury on jumps was highest of all terrain is limited so such training is by no means universal. In park features [3]. Another study comparing ski and addition, rider education efforts such as Burton’s ‘‘Smart snowboard injuries inside and outside terrain parks found Style’’ have been beneficial. Yet adoption of quantifiable that the percentage of spine and head injuries inside the engineering design of terrain parks has been resisted. At terrain park was double that outside [4]. The principal present, in the US at least, terrain park jumps are typically hazards may be succinctly summarized as landing ‘‘hard’’ fabricated at the individual resorts using little or no quan- and/or landing upside down. titative analysis or engineering design by staff with no Many snow-related head, neck and back injuries are formal training in engineering analysis of the designs. extremely serious. A succinct summary provided by Me- The reluctance of ski resorts to adopt an engineering yers and Misra [11] states: ‘‘spinal cord injuries (SCIs) are design approach may be traced to their risk management among the worst ski outcomes.’’ A broad review of SCI strategy. As gleaned from the waiver forms attached to lift epidemiological trends by Jackson et al. [12] found an pass agreements and recent presentations by ski industry increase in SCI caused by snow (as opposed to water) defense lawyers, one apparent component of the legal skiing, and that snow skiing (presumably including snow- strategy in the US is to assert that the responsibility for boarding) had replaced football as the second leading cause safety resides with the patrons. Aside from minimum of SCI in the US. Ackery et al. [13] published a review of diligence related to roping, signage, lifts, rental shop 24 articles between 1990 and 2004 from 10 countries and operations, and marking man-made obstacles, ski resorts found evidence of an increasing incidence of traumatic are reluctant to acknowledge additional responsibility for brain injury and SCI in alpine skiing and snowboarding the safety of their patrons. This is not to say resorts are not worldwide. They noted that this increase coincided with concerned about safety; they are very much so, but the ‘‘development and acceptance of acrobatic and high-speed point is that as part of their risk management legal strategy, activities on the mountain’’. resorts are reluctant to explicitly acknowledge additional By as early as the end of the 1990s, Tarazi et al. had responsibilities. This strategy extends to terrain park jump found that the incidence of SCI in snowboarders was four designs. Specifically, the NSAA asserts that, due to rider times that in skiers and that jumping was the primary cause and snow variability, terrain park jump ‘‘standards are of injury (77% of snowboarder SCIs occurred from jump- impossible’’ [18]. Thus, by this reasoning, engineering ing) [1]. In a review by Seino et al. [14] of six cases of design of winter terrain park jumps is likewise impossible, traumatic paraplegia SCIs resulting from snowboard acci- which enables resorts to argue that they are not liable dents at a single institution over 3 years, researchers found should anything go wrong. In essence, the apparent legal that they occurred to young men between the ages of 23 position of the industry is one whereby the resorts provide and 25, and that the primary fracture mechanism was a (possibly unsafe) terrain park jumps for their patrons who, backward fall from an intentional jump. in deciding to use them or not, bear the full responsibility Although the above published studies are compelling, for the consequences. today it is still difficult to get a precise snapshot of While the participants must bear primary responsibility overall terrain park injury statistics nation- or worldwide. for and control over their safety while using terrain park In the US, although the NSAA collects skiing and jumps, employing engineering design principles to improve snowboarding injury data, these data are not made pub- the quality and safety of the jumps could prevent or miti- licly available. gate the potentially tragic consequences of poor patron These most serious SCIs (resulting in paraplegia or decisions and otherwise minor accidents. Our central pre- quadriplegia) exact a very large cost on society. That they mise is that, although there is significant variability due to happen uniformly to young people and are permanently snow conditions and rider decisions, these variations are debilitating means that there is an enormous economic and bounded in understandable ways that nevertheless allow social cost (see [15, 16]). One would hope that these large engineering designs that accommodate the variability or costs would lead to a more careful and scientific approach render it irrelevant. Indeed, based partly on this view, the to the design and fabrication of those terrain park features Committee (F-27) on Snow Skiing of ASTM (previously primarily involved, but this has not been the case. the American Society for Testing and Materials) is con- Although terrain parks have improved in many ways sidering bringing recreational winter terrain park jumps over the years, the quality of the end product varies widely within its purview. It appears that engineering design from resort to resort. There do exist creditable training approaches may soon be applied to winter terrain park programs, such as ‘‘Cutter’s Camp’’ [17], that are intended jumps.