Jasper E. Shealy

A Method to Help Reduce the Risk of Serious Knee Sprains Incurred in Alpine Skiing

The incidence of severe anterior cruciate ligament sprains was once only a third the current rate. This fact led the authors to believe a means to help reduce the risk of anterior cruciate ligament injury among skiers might be found. Using videotapes of the occurrences of anterior cruciate ligament sprains in alpine skiers and the data associated with more than 1400 anterior cru ciate ligament injuries observed in a 22-year study, the authors identified two common mechanisms of anterior cruciate ligament injury. From this information, a study was designed to determine if training could help reduce the risk of anterior cruciate ligament sprains. During the 1993 to 1994 season, the on-slope staff from 20 ski areas participated in a training program involving view ing videotaped scenes where knee injuries occurred. Data from 22 ski areas, where staff were not exposed to the training, were assembled to form a control group. Data concerning anterior cruciate ligament injuries were collected from both groups for the three seasons 1991 to 1994. A total of 179 serious knee sprains were evalu ated. Serious knee sprains declined by 62% among trained patrollers and instructors compared with the two previous seasons, but no decline occurred in the control group.

Alpine ski bindings and injuries. Current findings.

In spite of the fact that the overall incidence of alpine ski injuries has decreased during the last 25 years, the incidence of serious knee sprains usually involving the anterior cruciate ligament (ACL) has risen dramatically since the late 1970s. This trend runs counter to a dramatic reduction in lower leg injuries that began in the early 1970s and to date has lowered the risk of injury below the knee by almost 90%.One of the primary design objectives of modern ski boots and bindings has been to protect the skier from tibia and ankle fractures. So, in that sense, they have done an excellent job. However, despite advances in equipment design, modern ski bindings have not protected the knee from serious ligament trauma.At the present time, we are unaware of any binding design, settings or function that can protect both the knee and lower extremities fromserious ligament sprains. No innovative change in binding design appears to be on the horizon that has the potential to reduce the risk of these severe knee injuries. Indeed, only 1 study has demonstrated a means to help reduce this risk of serious knee sprains, and this study involved education of skiers, not ski equipment.Despite the inability of bindings to reduce the risk of severe knee injuries there can be no doubt that improvement in ski bindings has been the most important factor in the marked reduction in incidence of lower leg and ankle injuries during the last 25 years. The authors strongly endorse the application of present International Standards Organisation (ISO) and American Society for Testing and Materials (ASTM) standards concerning mounting, setting and maintainingmodern ’state of the art’ bindings.

Snowboarding Injuries Trends Over Time and Comparisons With Alpine Skiing Injuries

Background: Participation in snowboarding as a winter sport is comparable to alpine skiing concerning the demographics of the participants, risk of injury, and variation in types of injuries sustained. Purpose: To examine the types of snowboarding injuries and changes in injury patterns over time. We also sought to highlight important differences in injury patterns between snowboarders and alpine skiers as affected by age, experience, and sex. Study Design: Case control; Level of evidence, 3. Methods: Data were collected on injured snowboarders and skiers in a base-lodge clinic of a ski resort in Vermont over 18 seasons (1988-2006) and included extensive information about injury patterns, demographics, and experience. Control data were also obtained during this time period to provide information about the population at risk. Results: The injury rates were assessed as mean days between injuries (MDBI). The average MDBI for all injuries among snowboarders was 345 as compared with 400 for skiers (the lower the number, the higher the injury rate). The most common type of injury for snowboarders was a wrist injury (MDBI, 1258), while for skiers, it was an anterior cruciate ligament (ACL) sprain (MDBI, 2332). Wrist injuries accounted for 27.6% of all snowboard injuries and 2.8% of skiing injuries, and ACL injuries composed 1.7% of all snowboard injuries and 17.2% of skiing injuries. Among snowboarders, more wrist injuries, shoulder soft tissue injuries, ankle injuries, concussions, and clavicle fractures were seen, while skiers had more ACL sprains, medial collateral ligament (MCL) sprains of the knee, lateral collateral ligament (LCL) sprains of the knee, lower extremity contusions, and tibia fractures. The trend analysis revealed an increased incidence of clavicle fractures (P < .01) and a decrease in MCL injuries (P < .01) and ankle injuries (P < .025) among snowboarders over time. Skiers had a decrease in thumb metacarpophalangeal-ulnar collateral ligament (MCP-UCL) injuries (P < .001) and MCL injuries of the knee (P < .001) over time. We found the highest rate of injury among young, inexperienced, female snowboarders. When examining the location of injury, 21.8% of snowboard injuries occurred in the terrain park compared with 6.5% of ski injuries. Conclusion: Injury rates in snowboarders have fluctuated over time but currently remain higher than in skiers. Wrist, shoulder, and ankle injuries are more common among snowboarders, while knee ligament injuries are more common in skiers. Injured snowboarders were significantly younger, less experienced, and more likely to be female than injured skiers or snowboard control participants. We did not find any evidence that those who spend time in terrain parks are overrepresented in the injury population.

The effects of complex wrist and forearm posture on wrist range of motion

Previous research on wrist functionality has focused almost entirely on range of motion (ROM) in 2 or 3 isolated planes (flexion/extension, radial/ulnar deviation, and forearm pronation/supination), without investigating the potential effects of complex wrist/forearm posture on ROM. A quantitative analysis of these effects on wrist ROM was performed. ROM was measured in one plane using both a manual method and an electrogoniometer while the participant maintained a fixed, secondary wrist and forearm posture. The study revealed that combinations of wrist/forearm postures have significant effects on wrist ROM; the largest effects are those of wrist flexion/extension on radial deviation ROM. The study also found that, consistent with previous research, wrist deviation measurements obtained with an electrogoniometer were significantly different from those obtained manually. Biomechanical theories for the results obtained are discussed. This research could be used to enhance ergonomic evaluation techniques by providing a more accurate risk assessment of certain complex wrist postures, particularly those in which wrist flexion/extension is combined with radial deviation.

Do Helmets Reduce Fatalities or Merely Alter the Patterns of Death

The use of helmets has been proposed as a means of reducing the incidence of fatality in skiing and snowboarding. This paper presents results that suggest that while helmets may be effective at preventing minor injuries, they have not been shown to reduce the overall incidence of fatality in skiing and snowboarding even though as many as 40% of the population at risk are currently using helmets. The results indicate that the use of a helmet will indeed influence the primary cause of death, but perhaps not the ultimate outcome.

Functional and Release Characteristics of Alpine Ski Equipment

Releasable bindings were developed to reduce the risk of lower leg injuries. However, the relationship between the incidence of specific alpine injury groups and the function and calibration of the release system has not been well understood. Over the 32 years between December 1972 and April 2004, the authors conducted a case control study at a northern Vermont ski area involving 17 967 injuries and 3617 uninjured controls. During that time, approximately 6.4 million skier visits were recorded at the area. Injured skiers were treated at clinic in the base lodge and their injuries diagnosed by the clinic staff. Data relating to the accident, the injury, and the equipment used were recorded. The release moments of equipment associated with lower extremity injuries and uninjured controls were measured using a commercially available test device. Case studies of 43 anterior cruciate ligament (ACL) sprains, 79 lower leg injuries, and 99 uninjured controls were conducted using data collected over seven years between December 1997 and April 2004. In terms of quantitative critical defects, 17 % of the control group, 14 % of the ACL group, and 39 % of the lower leg group exhibited release levels more than 30 % above recommended. When qualitative critical defects were considered, 27 % of the control group, 25 % of the ACL group, and 54 % of the lower leg group were found to exhibit one or more defects capable of having a significant effect on equipment function. The authors concluded that sprains, fractures, strains, and contusions of the lower leg among alpine skiers were associated with measurable or observable qualities of the release system. Serious sprains of the knee were not. A substantial reduction of injuries below the knee can be expected if potentially defective equipment can be identified and repaired, or replaced.

What do we know about ski injury research that relates binding function to knee and lower leg injuries

This review paper presents what is generally accepted today as scientific certainty in the field of alpine skiing; it is based upon knowledge that has been published in the peer-reviewed literature, presented at scientific meetings, or from other sources such as ski trade and consumer publications. The contents of the review come from a multitude of worldwide research, as well as from the 29-year case control study by the authors. In that case control study, the release binding system performance for controls and selected injury diagnosis groups has been evaluated under simulated loads using a device defined by the American Society for Testing and Materials (ASTM) standard F504 Standard Test Method for Measuring the Quasi-Static Release Moments of Alpine Ski Bindings, or by other test devices as defined by F1061 Specifications for Ski Binding Test Devices. The paper concentrates on common lower extremity injuries in skiing related to the unique mechanical properties of the ski-binding-boot system. It does not address non-lower extremity injuries, such as head, neck, upper body, etc. except in the context of possible inadvertent system release resulting in injury. KEYWORDS: ski injuries, epidemiology, binding function, lower leg injuries, tibial shaft fractures, knee injuries, injury mechanisms Language: en

A Relative Analysis of Downhill and Cross-Country Ski Injuries

This is a clinical analysis of XC and DH injuries reported thru the CPSC NEISS data files. It suggests that there are significant differences between the two sports and that there are occasionally significant interactions with gender as well. There are some implications with regard to injury mechanisms as well as hardware factors. In order to more fully understand and interpret these findings, it will be necessary to couple these findings with an examination of the populations at risk in a quasi-epidemiological methodology.

2010/2011 NSAA 10-Year Interval Injury Study

Skiing and snowboarding are common activities at ski resorts that may result in injury. In 1980, The National Ski Areas Association (NSAA) commissioned the first 10-Year Interval national injury study. This is the fourth such study. The objective of the study was to obtain estimates of the prevalence, incidence, and nature of snow sports injuries across the US. These studies are used to evaluate injury trends. The method for the study was to obtain Ski Patrol Incident data from selected ski resorts in the US on the basis of size and geographical location. The data were weighted by the % of resort visits based on size and location. National skier and snowboarder control demographic data came from the NSAA 2010 National Demographic Study. Resort visit totals came from the NSAA 2010 Kottke National End-of-Season Survey. A retrospective stratified study design was used. Statistical package for the social sciences (SPSS) was used to evaluate incidence trends using linear regression. Incidence rate differences were evaluated using t-test. Prevalence was evaluated using Chi-Square tests. The 0.05 level of significance was used. The sample areas generated 13 145 incident reports and 4 618 194 visitation days. The weighted skiing incident rate was 3.1 per 1000 visits in 1980, 2.7 in 1990, 2.6 in 2000, and 2.5 for 2010. The weighted 2010 snowboard rate was 6.1 per 1000 visits; it was 3.3 in 1990, and 7.0 for 2000. Ultimately, skiing injury rate continues to decrease. Snowboarding injury rate has decreased since the last study: injury patterns for snowboarding versus skiing is unchanged, injury patterns for males versus females is unchanged, incidence of jumping related incident reports has declined since last report, the prevalence of collision incidents with fixed objects on the slope decreased, and Terrain Parks are not associated with increase in injury rates or prevalence of jumping injuries. KEYWORDS: ski, snowboard, injury trend analyses Language: en

Reaction Times of Skiers and Snowboarders

Collisions with obstacles, such as trees, rocks, and other people, are a common occurrence in the sports of skiing and snowboarding. Once an obstacle becomes visible, whether or not the skier has time to avoid it is largely determined by that skier’s reaction time (RT)—the time it takes to detect and identify the obstacle, make a decision about how to respond, and initiate that response. Stopping and turning RTs were measured in ten expert skiers and four expert snowboarders at Mammoth Mountain, California. Participants were told to search for a sign along a closed intermediate course and to execute the instruction on the sign as quickly as possible. The sign was positioned such that it was not visible until participants crested a berm. Two high-speed video cameras captured the movements of each participant. RT was defined as the time between when the sign first came into view and when the skier or snowboarder initiated a response (the time of initial ski, snowboard, or body movement away from the original path or arc of the participant). The average RT for skiers and snowboarders was 856 and 1056 ms, respectively. No difference in RT was observed between stopping and turning responses. These data can be used to estimate the limits of performance for an attentive, experienced skier or snowboarder under good environmental conditions.