Windsurfing injuries: results of a paper- and Internetbased

Transcription

1 Wilderness and Environmental Medicine, 10, (1999) ORIGINAL RESEARCH Windsurfing injuries: results of a paper- and Internetbased survey ANDREW T. NATHANSON, MD, FACEP; STEVEN E. REINERT, MS From the Brown University School ofmedicine, Department ofemergency Medicine, Rhode Island Hospital, ProvidenCt', RI Objective.-To describe the frequency, pattern, and mechanism of windsurfing injuries. Methods.-A 24-question multiple-choice paper-based survey was distributed to windsurfers at beaches in the United States and the Dominican Republic, and an identical survey was placed on the Internet. Results.-Two hundred ninety-four surveys in all were completed describing 339 acute and 150 chronic injuries. The foot, knee, chest wall, and ankle were the most commonly injured body parts. Sprains (26.3%) were most common, followed by lacerations (21.2%), contusions (16.2%), and fractures (14.2%). Direct injury from the windsurfing apparatus resulted in 64.5% of the acute injuries, and 12% were caused by contact with the ocean floor. The maneuvers most likely to result in injury were jumping, high-speed falls, and catapult falls. There was no statistically significant difference between the Internet- and paper-based surveys regarding anatomic distribution of injuries or type of injury. The incidence of injuries requiring medical care in study participants was estimated to be one injury per 1000 days sailed. Conclusions.-Sprains, lacerations, and contusions to the lower extremity are the most common windsurfing injuries. Equipment modifications are suggested that may decrease the risk of injury. Key words: windsurfing, injury, Internet, survey Introduction 'Windsurfing is a water sport that is a hybrid of surfing and sailing. It was invented in Southern California in 1969 by Hoyle Schweitzer and Jim Drake. The original Windsurfer was an 11lh-foot, 42-pound surfboard connected to a hand-held sail by means of a flexible universal joint. This ingenious "free sail" system allows the board to be steered by moving the sail fore and aft, without the use of a traditional rudder. The sailor stands parallel to the board and grips the wishbone boom at shoulder width. Footstraps on the board allow the sailor to maintain control of the board in rough water and while airborne. Harness lines hanging from the booms may be engaged with a harness hook worn around the waist, enabling the sailor to sail for long periods of time with less fatigue (Figure 1). Windsurfing grew rapidly in the 1980s, particularly in Corresponding author: Andrew T. Nathanson, MD, Department of Emergency Medicine. Rhode Island Hospital. 593 Eddy Street. Providence, RI the coastal United States, Hawaii, Europe, and Australia. The sport became a new yachting event in the 1984 Olympics. In 1995, it was estimated that there were 2 million windsurfers in the United States and over 1I million woridwide. 1 Initially, the sport was practiced only on relatively heavy, stable longboards (>I I feet long) primarily on lakes and protected bays in low and medium winds of less than 15 knots. More recently, the trend has been toward lighter shortboards sailed in higher winds on rougher, more exposed waters. Shortboards are between 8 and 10 feet long, are more maneuverable, and are capable of much higher speeds. Over the last IS years, the sport has evolved to include the distinct disciplines of longboard triangle racing, shortboard slalom racing, and shortboard wave sailing. International competition in these three events occurs at both amateur and professional regattas. Much like the differences between downhill and cross-country skiing, the equipment, speeds, and injury patterns are different in each discipline. 2 The official speed record was 28 mph in 1980 and increased to 36 mph in The current speed record

2 Windsurfing injuries 219 Figure 1. Modem shortboard with sailor hooked into harness, feet in footstraps. is 50 mph, and recreational sailors now routinely reach speeds of 30 mph. Advanced wave sailors are capable of jumps in excess of 25 feet high and are capable of completing inverted aerial maneuvers such as forward and backward loops. Both equipment and maneuvers continue to evolve. Relatively little has been written about windsurfing injuries in the medical literature. A recent literature search found only five studies published in the English language. These studies have shown that the most common injuries are abrasions and lacerations to the lower extremities. 2,3 In a study of 67 injuries requiring medical attention, 30% involved tom knee ligaments, and 27% were due to head and neck trauma. 4 Pectoralis muscle rupture, urethral injury, and shoulder dislocation have au been reported. 5-7 The purpose of this study was to gather more information regarding windsurfing-related injuries. A 24- question survey was distributed to windsurfers at windsurfing beaches and via the Internet. Each injury was analyzed with regard to anatomical location, type of injury, severity of injury, mechanism of injury, wind strength, water conditions, type of board, and protective gear worn. These injuries were cross-referenced with the age, sex, physical conditioning, and sailing ability of each subject. We hope that identifying the most frequent injuries and their mechanisms will result in improvements in equipment design and will lead to recommendations in protective gear. Further, injury patterns identified may help physicians know what to expect and consider when caring for an injured windsurfer, thus improving the standard of care. We also wanted to test the feasibility of an Internetbased survey and compare its results to that of a traditional written survey.

3 220 Nathanson and Reinert Materials and methods A 24-question, multiple-choice, single-page survey was developed in April 1994 after several earlier surveys had been piloted. The survey was broken up into sections on demographics, acute injury description, and chronic injury. The demographics section collected data regarding the subjects' age, sex, physical conditioning, windsurfing proficiency, years of participation in the sport, average days of participation per year, protective gear worn, and chronic injuries. The injuries section collected data regarding the anatomic location of injury, type of injury, severity, mech-. anism, wind speed, water conditions, type of windsurfing equipment used, and protective equipment worn at the time of injury. Space was provided for text comments. More than one injury could be separately described by each subject. For questions for which an appropriate multiple-choice answer was not included, a free text "other" blank could be filled in. The questionnaire was distributed to a convenience sample at windsurfing sites in California, Rhode Island, Massachusetts, Hawaii, and the Dominican Republic. Between April 1994, and April 1997, 64 printed questionnaires were distributed and 50 were returned. Information from these forms was manually entered into an electronic database program (Panorama 3.0). An identical survey was put on a Web page using the Brown University Bio-Med server. The Web address of the survey was posted on the windsurfing newsgroup rec.windsurfing and distributed to the windsurfing E mail distribution lists, wincltalk@opus.hpl.hp.com and windsurfing@fly.com. The Web page went on line February 1997, and by May 1997,279 questionnaire forms were returned via the Internet. Information from these forms was directly downloaded into a database program (Panorama 3.0). The independent-sample t test and the chi-square test were used where appropriate, with a P value of.05 considered statistically significant. Statistical analyses were performed with Stata 5.0 (Stata Corp, College Station, TX). Questionnaire results were excluded if the responses were internally inconsistent (eg, wrist hypothermia or head sprain), if there were sections inappropriately left unanswered, or if all answers were left blank. If an identical Internet survey was submitted twice by the same individual (by pressing the "submit" button twice), only one copy of the data was entered in the final results. Results Fifty paper surveys were completed and returned. Two were excluded because sections were incomplete. Two hundred seventy-nine Web surveys were returned. Thirty-three (12%) of these Web surveys were excluded because the entire survey, or sections of it, were incomplete. No questionnaires of either type were excluded because of internal inconsistencies. A total of 294 subjects were included in the results. These subjects reported 339 acute injuries and 150 chronic injuries. One hundred twenty-five subjects reported 1 acute injury, 66 reported 2 acute injuries, and 23 reported 3 or more acute injuries. Forty-seven subjects reported no acute injuries. DEMOGRAPHICS The mean age of the study subjects was 35.5 years (SD := 9.3, range 15-70). Ninety percent of subjects were men. Mean time of participation in the sport was 9.2 years (SD := 4.8). The mean days sailed per year was 48 (SD := 40). Seven percent of the subjects rated themselves as beginners, 60% as intermediates, and 33% as experts. Included in the experts' category were two professional sailors. Participants in the study carne from 24 countries on six continents. The majority (67%) were from the United States, 10% were from Canada, 4% from Australia, 3% from the United Kingdom, and 16% were from other parts of the world. Three quarters of the study population stated that they used protective footwear, one fifth wore life vests, and 1 in 10 regularly wore helmets. ACUTE INJURIES Mechanism Direct injury from the windsurfing apparatus resulted in 64.5% (213) of all acute injuries (Figure 2). Twelve percent (40) of the acute injuries were caused by contact with the ocean floor, and 20% (66) were caused by some other mechanism. Of the injuries caused by equipment, 17.2% (57) were from the boom, 16.7% (55) were from the footstrap, 12.7% (42 ) were from the mast, 8.7% (29) were from the board, and 8.1 % (27) were from the fin. Injuries were nearly equally distributed between those caused by the board and its attachments and those caused by the sailing rig. Impact with the water resulted in nine injuries. There were two collisions with other windsurfers and one collision with a personal watercraft. The most common maneuver resulting in injury was jumping, which caused 21 % (71) of all acute injuries. Included in this category are loops (inverted jumps), which contribute to a small percentage of that total (Table 1). Because less than 5% of even the most active windsurfer's time is spent jumping, this maneuver con-

4 Windsurfing injuries 221 Mechanism ofinjury (n =339) Table 1. Maneuver resulting in injury (n = 339) % oftotal Maneuver Percentage of Total [ 12.7 Mast 1 Sail Collision 17.3 Boom 16.7 Foot Strap 4 Board (Unspecified) 2.7 Nose of board r Rail of board 1 Tail of board 2.7 Water 8.2 Fin 3 Marine Animal 9.1 Sea floor 19.6 Other Figure 2. Percentage of acute windsurfing injuries by reported mechanism. tributed a disproportionately high number of injuries. High-speed falls accounted for 18% (61) of the acute injuries, and being catapulted (thrown by one's harness) accounted for another 14% (47). If high- and low speedfalls and catapults are combined, these uncontrolled falls accounted for 37% (125) of all injuries. Beach starting, launching, or dismounting comprised 14% of the total. Less common maneuvers resulting in injury included jibing, waterstarting (using the force of sail to get onto the board), and sailing. Type and severity of injury Table 2 summarizes the types of acute injury reported. The most common were sprains, lacerations, contusions, and fractures. Less common injuries included abrasions, marine envenomations, near drowning, and hypothermia. Respondents sought medical care for less than half (42%) of these injuries, and only 3% required hospitalization. Of the 144 injuries requiring medical care, one third (48) were sprained or tom ligaments, one quarter (36) were fractures, and one quarter (36) were lacerations. Other severe injuries included dislocations, intervertebral disc injury, and contusions. Jumping, looping, and catapult falls were statistically more likely to result in injury requiring medical care (P ::=.02). Anatomic location of injury Table 3 summarizes the location of acute injuries. The lower extremity accounted for 45% (151) of all acute Jumping High speed fall Catapult fall Launching Jibing Water starting Low-speed fall Sailing Beach starting Wave riding Uphauling Looping Dismounting Rigging Other injuries, with the foot the most commonly injured body part. The knee and the ankle were also often injured. Of the 65 foot injuries, 31 (48%) were lacerations, 9 (14%) were fractures, and 9 (14%) were contusions. Of the 32 knee injuries, 18 (56%) were sprains, and 7 (22%) were tom ligaments or cartilage requiring surgery. The 29 ankle injuries included 17 (59%) sprains and 4 (14%) fractures. Not surprisingly, three quarters ofthe lower extremity fractures and ligamentous injuries were the result of the foot being engaged in the footstrap. There were 51 lacerations or puncture wounds to the lower extremity; 23 (45%) were the result of contact with the ocean floor. Shells, coral, sea urchins, needle fish, and scorpion fish were all identified as culprits. Table 2. Type of acute injury (n = 339) Injury Type Sprain Laceration Contusion Fracture Ligament tear Dislocation Disc herniation Abrasion Sting Near drowning Hypothermia Concussion Other Percentage of Total

5 222 Nathanson and Reinert Table 3. Anatomic location of acute injuries (n = 339) Body Region % Head and neck 17.8 Upper extremity Trunk Lower extremity Body Part % Head 7.4 Neck 4.7 Face 3.5 Eye 0.9 Nose 0.9 Teeth 0.9 Shoulder 7.1 Hand 4.4 Wrist 3.5 Ann 3.2 Elbow 0.3 Chest wall 8.9 Back 6.8 Foot 17.7 Knee 9.4 Ankle 8.6 Leg 7.4 Toe 1.5 Other 2.9 Nineteen (37%) lower-extremity lacerations were c~used by the fin of the board; 13 from long narrow "blade" fins, and 6 from shorter, swept-back "wave" type fins. Most of these lacerations occurred when the fin was accidentally struck while attempting to waterstart. Head and neck injuries accounted for 17.8% of all acute injuries. Of the 45 injuries to the head, 18 (40%) were lacerations, including 10 facial lacerations, 16 (40%) were contusions, and there was one concussion. There were also three tooth avulsions, three nasal fractures, and two tympanic membrane ruptures. Thirty-six percent of the head injuries were caused by the mast and 27% were caused by the boom. The upper extremity accounted for 18.5% of all acute injuries. Of these 62 injuries, there were 34 (55%) ligamentous injuries (24 sprains, 9 tom ligaments), 9 (15%) shoulder dislocations, 8 contusions, and 6 fractures of the hand or wrist. Sixteen percent of acute injuries were to the trunk, including 21 rib fractures, 7 rib contusions, 8 intervertebral disc injuries, and 8 back strains. Rib fractures accounted for 44% of all fractures, making this by far the most common type of fracture. Seventy percent of rib injuries resulted from contact with the boom, the majority of these from high-speed falls or catapults. Conditions and equipment Forty-four percent of the acute injuries occurred in choppy waters and 25% in flat water. Eighteen percent of the injuries took place in the surf and 13% in open ocean swells. The average wind speed at time of injury was 23 mph (SD = 7.2). There was no significant difference in wind speed (P =.3) between those injuries requiring medical care and those not requiring medical care. Seventy-two percent of participants were riding shortboards at the time of their injury; the others were riding longboards. Chronic injuries One hundred fifty chronic injuries were reported by 294 subjects. Lower-back pain was reported by 16% (47) of all respondents and neck pain by 10% (29). Lower-back pain was significantly more common among longboard sailors than those sailing shortboards (P =.005). Tendinitis of the elbow (11%), wrist (8%), and shoulder (3%) were also commonly reported. Carpal tunnel syndrome was described by 5% of subjects. Discussion This is the largest study of windsurfing injuries to date (n = 489) and has the most diverse demographic population. Prior studies by Allen and Locke, 2 Mettler and Beiner,3 McCormick and Davis,8 and others focused on elite Olympic longboard sailors, members of a windsurfing club, or sailors in a single geographic area. We included sailors of diverse abilities and experience in multiple sailing sites of 24 different countries. This is the first study to closely examine the mechanism, maneuver, equipment type, and wind and water conditions that contributed to each individual injury. We used the Internet as an inexpensive and effective way to disseminate a survey to a widely scattered population and to collect that data electronically. Using this relatively new resource, survey results may be tallied without the burden and potential errors of manual data entry. Our initial concerns that the results from the Internet would contain a lot of erroneous nonsense data were unfounded. When the data gathered from the Web were analyzed on a case-by-case basis, there were no internally inconsistent responses. Further, the free text descriptions describing individual injuries were undoubtedly written by people with an intimate knowledge of the sport. The injury pattern was very similar between the group responding to the paper survey and the group responding via the Internet. There was no significant difference between the two groups regarding body part injured (P = 0.28) or type of injury (P = 0.17). The demographics of the group who completed the questionnaire on paper were very similar to the Web responders. The average

6 Windsuifing injuries 223 age of those responding on paper was 35.5 years vs 35.6 years responding to the Web survey. The average number of years of experience windsurfing was 10 years for those responding to the paper survey vs 9 years for those responding to the Web survey. There was no statistically significant difference between the two groups for number of sailing days per year (P = 0.32). A statistically significantly higher percentage of women responded to the paper survey (21% vs 7%). In general, the results from the paper survey and the Internet survey were very similar, suggesting that the Internet is a useful tool for rapidly collecting a large sample of injury surveillance data. Other researchers using the Internet to gather survey data have made the same conclusion. 9 An Internet-based survey enjoys the benefits of low cost, wide dissemination, and computerized data entry. Using the average reported number of years windsurfing and the average reported number of days per year sailed, the incidence of significant injuries (that is, injuries for which the respondants sought medical care or were hospitalized) was estimated at roughly one injury per 1000 days sailed. By comparison, alpine skiing has 3.2 injuries per 1000 skier days, and cross-country skiing has less than one injury per 1000 skier-days.1o Ifthe average day sailed is estimated to be 3 hours' sailing time, then the incidence is 0.36 significant injuries per 1000 hours sailed. In his survey-based study of 73 windsurfers, McCormick 8 reported 0.22 significant injuries (defined as days lost from sports participation or the seeking out of medical care) per 1000 hours sailed. STUDY LIMITATIONS AND FUTURE DIRECTIONS The calculation of injury rates is subject to several significant limitations. Injury data are subject to reporting bias in that people with injuries are more likely to fill out a survey than those without injuries. This would falsely increase the calculated injury rates. Recall bias plays a role because individuals may not remember all injuries they have sustained while windsurfing and are more likely to remember the more severe injuries. The relative anonymity of the Internet may encourage false reporting. Further bias may be introduced because the on-line survey was limited to those with Internet access, which may not be a representative sample of all participants in the sport. The reliance on self-described injuries by nonmedical responders could also lead to erroneous data. As in all surveys, since this descriptive data is not population-based, direct conclusions should not be generalized to the sport as a whole. In order to establish a more accurate pattern and in- cidence of windsurfing injuries, a cohort of sailors could be followed prospectively. Another prospective study design would be to document all windsurfing injuries presenting to emergency departments located near heavily sailed sites, such as Maui, HI, or the Columbia River Gorge, OR, where treatment options are limited to a few local hospitals. However, the number of patients at risk for injury in such studies would be difficult to calculate, and minor injuries would be missed. SIGNIFICANT FINDINGS This study found that the lower extremity was the most commonly injured part of the body (44%). This finding is similar to that of Habal,4 who reported that 45% of all serious injuries were to the lower extremities. Ullis and Anno!! found that approximately 30% of injuries to competitive sailors in Hawaii were to the lower extremities. However, our study showed significantly more ankle injuries (9.4%) than those of UIlis and Anno ll (3.2%) or Habal 4 (l%). We also found double the percentage of foot and ankle fractures than the two other studies. This may be because those studies were published more than 10 years ago, when the use of footstraps was not universal. This study found a higher percentage of significant orthopedic injuries than had been reported by earlier investigators. We found that 26% of all injuries were sprains, 14% were fractures, and 4% were joint dislocations. By contrast, Mettler and Beiner,3 in a study of 189 members of the Swiss Sailboarding Federation, found that 16% of injuries were sprains, 3% fractures, and 0.6% dislocations. Allen and Locke 2 reported approximately 10% sprains, 3% fractures, and no dislocations. Both of these studies focused primarily on longboard sailors, who usually sail in lighter winds and at lower speeds than do shortboard sailors, who made up three quarters of our population. Another important finding is the 21 rib fractures (6% of all injuries) reported in our study. Habal 4 reported 1.3% "chest wall" injuries in a study of 153 injuries. Neither Ullis and Anno ll nor McCormick and Davis s reported any rib fractures. This may be due the lowered chest level boom height that has been adopted by most sailors over the last 5 years. It is also likely that the higher speeds attained on today's more efficient modem boards and sails result in higher-energy injuries. Chronic lower-back pain was found to be more common among longboard sailors than shortboard sailors (P =.005). This finding is borne out by Allen and Locke's2 study of 41 longboard sailors, 56% of whom reported chronic back problems, whereas Ullis and Anno'sll study of shortboard sailors found that only 10% of men had chronic back problems. This may be due to different

7 224 techniques used to raise the sail once it has fallen in the water (uphauling vs waterstarting); it may also be attributable to the fact that longboard racers are often in a static stance for long periods of time as compared with the variety of positions used by shortboard sailors. Board contact events resulted in 65% of all injuries in this study and 75% of all injuries reported by Mettler and Beiner 3 The boom, footstraps, mast, and fin were most often implicated. Nathanson and Reinert teet the chest wall from injury with the boom. The use of flotation vests in large surf is controversial, as some expert sailors feel they impede recovery of lost equipment, especially when trying to duck under oncoming waves. It is particularly important that protective equipment be worn when attempting jumps and loops, as these maneuvers accounted for over 20% of all injuries and a disproportionate number of severe injuries. SUGGESTED EQUIPMENT MODIFICATIONS Improved design of windsurfing apparatus may prevent many injuries and requires further study. Development of a break-away footstrap may reduce the incidence of lower extremity ligamentous injuries and fractures in the same way that multimode release bindings used in alpine skiing reduced the number of lower leg injuries in skiers. JO We found that three quarters of these injuries are caused by rotational forces generated by the long lever arm of the board against the foot wedged in the footstrap. Most professional sailors have their footstraps adjusted to allow the midfoot to be covered by the strap. They feel the added control of the board they gain more than offsets the difficulty in exiting the footstrap. Less experienced sailors who are more likely to experience unexpected falls should probably adjust the footstrap to allow only the forefoot in, allowing a faster exit. Fins with duller or softer edges and shorter lengths would likely reduce the number of lacerations caused by the fin. The recent trend toward longer, more pointed blade fins raises concerns because of their potential for serious injury. From conversations with study respondents, we are aware of four deaths caused by penetrating fin trauma. A harness hook that disengaged from the harness line at a load equal to the sailor's body weight could prevent injuries obtained from being catapulted. This maneuver accounted for 14% of all injuries. Catapulting often occurs in gusty winds with intermediate-level sailors who are unable to disengage the harness rapidly and thus are launched into the air, often landing on the booms or mast. SAFETY RECOMMENDATIONS Personal safety gear should include the use of punctureresistant footwear to prevent foot lacerations and injury from marine animals. Helmets should be worn to prevent head injury from the mast and from collisions with other sailors. The addition of a facemask protects the face and teeth. Personal flotation devices would potentially decrease the incidence of drowning and also serve to pro- Conclusion Windsurfing appears to be a relatively safe sport when compared with other thrill sports such as alpine skiing. The majority of injuries are sprains, lacerations, and contusions. Fractures and dislocations appear to be increasing in frequency, perhaps as a result of the current emphasis on high-wind shortboard sailing and the higher speeds attained on efficient, modem windsurfing equipment. Lower-extremity injuries are most common, followed by upper-extremity, head and neck, and trunk injuries. Jumping is a high-risk maneuver that results in a disproportionate number of severe injuries. The results of a paper-based survey on Windsurfing injuries are statistically very similar to those of an identical Internet-based survey. The Internet-based survey instrument simplifies data collection and data processing and provides easy access to a large number of individuals worldwide. Acknowledgment A.T.N. thanks his father, Dr Larry Nathanson, without whose encouragement and insight this paper may never have been written. References 1. Van Tilburg C. Windsurfing medicine. Surfing Med. 1995; 14: Allen GD, Locke S. Training activities, competitive histories, and injury profiles of elite boardsailing athletes. Aust J Sci Med Sports. 1989;21: Mettler R, Beiner K. Athletic injuries in windsurfing. Schweiz Z Sportmed. 1991;39: Habal MB. Athletic injuries caused by the new sport of windsurfing and a proposed set of preventive measures. J Fla Med Assoc. 1986;73: Jespersen S, Wettergren A. Shoulder dislocation caused by windsurfing. Ugeskr Laeger. 1988;150: Senn E, Bandhauer K. Urethral injuries due to windsurfing. Schweiz Z Sportmed. 1982;30: Dunkelman NR, Collier F, Rook JL, et al. Pectoralis major muscle rupture in windsurfing. Arch Phys Med Rehabil. 1994;75:

8 Windsurfing injuries 8. McConnick Dp, Davis AL. Injuries in sailboard enthusiasts. Br J Sports Med. 1988;22: Trissel D, Alexander RB. Chronic prostatitis: results of an Internet survey. Urology. 1996;48: Hartung HG, Goebert DA. Watersports injuries. In: Caine 225 D, Caine C, Koenraad L, eds. Epidemiology ofsports Injuries. Champaign, IL: Human Kinetics Publishers; 1996: Ullis KC, Anno K. Injuries of competitive board sailors. Phys Sports Med. 1984;12:86-93.