This article was published in an Elsevier journal. The attached copyis furnished to the author for non-commercial research and

education use, including for instruction at the author’s institution,sharing with colleagues and providing to institution administration.

Other uses, including reproduction and distribution, or selling orlicensing copies, or posting to personal, institutional or third party

websites are prohibited.

In most cases authors are permitted to post their version of thearticle (e.g. in Word or Tex form) to their personal website orinstitutional repository. Authors requiring further information

regarding Elsevier’s archiving and manuscript policies areencouraged to visit:

http://www.elsevier.com/copyright

Author's personal copy

Accident Analysis and Prevention 40 (2008) 787–797

Risk factors and prevention for spinal cord injury fromdiving in swimming pools and natural sites

in Quebec, Canada: A 44-year study

Peter Barss a, Hind Djerrari b, Bernard E. Leduc c,∗,Yves Lepage d, Clermont E. Dionne b

a Department of Epidemiology, Biostatistics, and Occupational Health, McGill University (at time of research),Now at Department of Community Medicine, Faculty of Medicine, United Arab Emirates University, Al Ain, United Arab Emirates

b Population Health Research Unit, Universite Laval, Quebec, Canadac Department of Physical Medicine and Rehabilitation, Institut de readaptation de Montreal, Quebec, Canada

d Department of Mathematics and Statistics, Universite de Montreal, Quebec, Canada

Received 27 June 2007; received in revised form 27 August 2007; accepted 12 September 2007

Abstract

Background: Diving is the most frequent cause of spinal cord injury (SCI) from recreation and sport in Canada. This study was done to identifyrisk factors for SCI from diving in the province of Quebec.Methods: An interview survey was done for a target population of 203 subjects with a SCI from diving treated in the two specialized rehabilitationcenters in Quebec during 1961–2004. Telephone interviews of consenting individuals were used to collect pertinent personal, equipment, andenvironmental factors for each incident.Results: Response was 44% (89/203); 92% were male and 85% <35 years old. Only 37% were aware prior to injury of the risk of SCI from diving,and only 33% had received water safety training. Swimming pools were the site of 51% (n = 45) and natural bodies of water for 49% (n = 44). 87%(n = 39) of pools were single-unit home pools and 57% (n = 26) above-ground. Depth indicators were absent for 100% of above-ground and 74% ofin-ground pools. For SCI in in-ground pools, 63% resulted from striking the up-slope between deep and shallow ends. For dives at natural sites, adock or wharf was the most frequent location, 36% (n = 16). In 52% of pools and 79% of natural sites, depth was <1.4 m (4.6 ft). Signs prohibitingdiving were absent in 96% of above-ground and 89% of in-ground pools. Alcohol was reported in 47% of SCIs.Interpretation: The target for prevention of diving SCI is male youths and young adults. Above-ground pools are too shallow and small for diving.Deep ends of many in-ground pools are excessively shallow and short since many SCIs resulted from striking the up-slope. Prevention of SCI fromdiving needs to focus on education of potential victims, pool vendors and manufacturers, and regulations for safety norms in private pools. Watersafety should highlight diving as a high-risk activity, and emphasize that most home pools and natural sites are unsafe. Safer evidence-based pooldesigns and more effective warnings need to be implemented.© 2007 Elsevier Ltd. All rights reserved.

Keywords: Spinal cord injuries; Diving/injuries; Spinal cord injuries/epidemiology; Spinal cord injuries/aetiology; Spinal cord injuries/prevention and control;Swimming pools; Tetraplegia

1. Introduction

Spinal cord injury (SCI) has devastating personal and eco-nomic consequences for victims, their families, and society.

∗ Corresponding author at: Institut de readaptation de Montreal, 6300 Dar-lington Ave., Montreal, Quebec, Canada H3S 2J4. Tel.: +1 514 340 2770;fax: +1 514 340 2775.

E-mail address: leduc 51@sympatico.ca (B.E. Leduc).

There are estimated to be 132,000 incident cases per yearglobally, an annual rate of 22 per million population (ICCP,2001). While global data are not available on the incidenceof sports-related SCI, in the United States and Europe sportaccounts for 9–10% of all SCI (Parliamentary Assembly, 2002;NSCISC, 2005). In many industrialized countries, includingthe United States, diving is the source of the majority ofsports-related SCI and is therefore a priority for sports injuryprevention.

0001-4575/$ – see front matter © 2007 Elsevier Ltd. All rights reserved.doi:10.1016/j.aap.2007.09.017

Author's personal copy

788 P. Barss et al. / Accident Analysis and Prevention 40 (2008) 787–797

The relative importance of diving as a cause of SCI variesenormously by country, ranging from 1 to 23%, with lowsin Japan, Turkey, and South Africa, mid-range in Australia,Canada, and the United States, and highs in Poland and Russia(ICCP, 2001; Parliamentary Assembly, 2002; NSCISC, 2005,2006; Blanksby et al., 1997; Karacan et al., 2000; Kiwerski,1993; Djerrari, 2000; O’Connor, 2002; RCIS, 2006; Griffiths,1980; Aito et al., 2005; DeVivo, 2003). While diving is muchless frequent as a source of SCI than traffic injuries, falls, andviolence in the United States, it was still the fourth leading causeat 7%, with about 770 diving SCIs per year, and the leadingsource for recreation and sport (NSCISC, 2005, 2006). All sportsinjuries combined accounted for 9% of SCI, with nearly 80%of this contributed by diving; however, the relative importanceof diving shows large racial differences in the United States(DeVivo, 2003). Elsewhere, in the Spinal Unit in Florence, Italy,diving injuries similarly comprised 62% of SCI from sports, and6% of all SCI (Aito et al., 2005).

Diving ranked higher as a cause of SCI in Canada, and inAustralia, than in the United States, where gunshots/violencewere third at 14% (Djerrari, 2000; O’Connor, 2002; RCIS,2006; Griffiths, 1980; NSCISC, 2005, 2006). In the provinceof Quebec, Canada, diving ranked third as a cause of SCI during1981–1994, accounting for 6% of SCI overall (Djerrari, 2000).While population-based incidence rates provide a better indi-cator of frequency and burden of SCI from diving and othercauses than do proportions and ranks, rates are rarely reported.Even better would be exposure per swimmer, diver, dives, andso forth, together with national information about prevalenceof pools with different attributes, but such data are currentlyunavailable.

Incidence and proportions for Quebec province, Canada, anda few other countries are shown in Table 1. In both Quebec andCanada, incidence rates were about 10 times higher for malesthan females, and the main risk groups by age were 15–44 years(Djerrari, 2000). Although the average incidence in Quebec wasslightly less than for the rest of the country during 1981–1994,greater improvement was evident in other provinces. During

1991–2000 in Canada, there were 31 head and/or spinal injurydeaths from diving reported by coroners, an average of about 3per year, or 1 per 10 million population (Barss, 2006).

It is reported that in all dives, velocity at maximum depthexceeds that required to dislocate cervical vertebrae, and in99% is sufficient to crush them (Blitvich et al., 2003a,b; Stone,2003). In some cases of SCI there is neither dislocation norfracture, and only spinal cord contusion is found. Clearly, anydive can potentially result in a lifetime of severe disability, ordeath.

On average, diving SCI are more disabling than SCI fromtraffic or falls as nearly all are cervical and result in tetraple-gia rather than paraplegia (DeVivo and Sekar, 1997; NSCISC,2005). Hence in countries where diving injuries are an importantissue, this cause assumes greater prominence as a source of cer-vical SCI. To illustrate, in Australia, diving accounted for about10% of admissions to spinal units, but for 20% of tetraplegias(O’Connor, 2002; RCIS, 2006; Griffiths, 1980). However, in theUnited States, 88% of SCIs from sports, mainly diving, resultedin tetraplegia, compared with road injuries 55%, falls 53%,and violence 29% (NSCISC, 2005). Even among tetraplegias,severity was greater for sports, with 46% complete tetraplegiasand 54% incomplete, compared with motor vehicles 40% com-plete, and falls 29% complete; only tetraplegias from violencewere more severe, 52% complete (NSCISC, 2005). Urbaniza-tion also affects relative importance of diving as a source ofcervical SCI; in Poland, diving accounted for 31% of cervicalSCIs of urban residents and 11% for rural, whereas among ruralresidents, falls from farm horse carts made up 42% (Kiwerski,1993).

External causes of SCI vary by age. Road injuries and sport,and in the United States, violence, are frequent among childrenand young adults and falls are among older adults (NSCISC,2005). Hence, the combination of young age of most diving SCIvictims plus severity of SCI means that economic costs of careare much greater than for most other causes, not to mention thelarge loss of disability-free life years (NSCISC, 2005; DeVivo,1997).

Table 1Incidence and proportion of spinal injuries from diving for Quebec and other populations

Population Time period Average/incidence/million/year Percent SCI due to

Diving (%) Falls (%) Traffic (%) Other (%)

Quebec, Canada (Djerrari, 2000) 1981–1994 2.1 6 30 58 8Quebec, Canadaa 1999–2003 1.7 5Ontario, Canadab (Tator et al., 1981) 1981 1.7 10Canada (Djerrari, 2000) 1981–1994 2.4United States (NSCISC, 2005, 2006) 1973–2004 2.8 7 23 48 23Europec (Parliamentary Assembly, 2002) 2001 1.0Austria (Schwarz et al., 2001) 1991–1998 1.0Australia (O’Connor, 2002; RCIS, 2006) 1998–2000 1.2 10Turkey (Karacan et al., 2000) 1992 0.15 1 36 49 14

a Unpublished data, 2004, Ministry of Health and Social Services of Quebec: about 12 cases of cervical SCI/year from diving, 1999–2003, out of 230–250 cases,50% cervical, of SCI/year from all causes.

b Incidence was calculated using estimated numbers of SCIs in source article and 1981 census population.c In Europe, 10% of an estimated 14 per million incident cases per year are from sport; based on US data, we conservatively estimated about 70% of sports SCI

due to diving.

Author's personal copy

P. Barss et al. / Accident Analysis and Prevention 40 (2008) 787–797 789

To better address SCIs from diving in Quebec and to improveprevention programs, we investigated personal, equipment, andenvironmental risk factors among patients with a diving SCI whohad been treated in either of the two major Quebec rehabilitationhospitals.

2. Methods

2.1. Study design and time period

Because diving SCIs are uncommon catastrophic injuries,we undertook a retrospective survey for the 44-year period(1961–2004) for which files were available, interviewing vic-tims contacted via the two main rehabilitation hospitals. Thestudy began in 1996 and was completed with an update during2004–2005.

2.2. Target population

This included all known survivors of SCI from diving intoshallow water. After the acute period, most patients are treated ineither the Institut de readaptation de Montreal (IRM) or the Insti-tut de readaptation en deficience physique de Quebec (IRDPQ).Quebec is the second most populous province in Canada with apopulation of 7.5 million; at study midpoint it was 6.5 million.

2.3. Data sources

Diving SCIs were identified with MedEcho, the provin-cial hospital database, using International Classificationof Diseases, Ninth Revision (World Health Organization,1978). This database includes all injured persons hospi-talized for >24 h and employs well-trained professionalcoders. Personal, equipment and environmental risk factorswere obtained by telephone interview. Since patients werecontacted only by telephone, impairment was not evalu-ated with the American Spinal Injury Association (ASIA)scale, nor was point of impact or exact level of injuryassessed.

2.4. Inclusion criteria

This study included persons with cervical SCI from divingsustained in Quebec with hospital stays of >24 h treated at IRMor IRDPQ; hence, deaths prior to transfer or minor injuries wereexcluded. SCIs due to diving are identified by external causecode E883.0, together with nature of injury codes 806.0–806.1(cervical spine fracture with SCI), and 952.0 (cervical SCI with-out spinal bone injury), or code 344 tetraplegia (World HealthOrganization, 1978). While E883 includes injuries from bothdiving and jumping, it is unlikely that jumping causes cervicalspine injury, and, in any case, diving was confirmed during inter-views. Other diving injuries and deaths prior to hospitalizationwere not assessed.

2.5. Sampling and ethical approval

Following approval by hospital ethics committees, all divingSCI admissions during 1961–2004 were selected. Confidential-ity guidelines do not allow contact between researchers andpatients until the hospital obtains informed consent. The medicalrecords department sent out our explanatory letters to eligiblepatients; those who consented were interviewed. Four letterswere sent to each before considering them non-contactable.

2.6. Data collection instruments

An interviewer-administered questionnaire with 56 mainlystructured closed-ended questions covering demographics andrisk factors was developed, reviewed by external experts in injuryprevention, and pre-tested. Trained interviewers averaged about30 min per subject.

2.7. Data analysis

Data were doubly entered and compared for keystroke errors,then transferred to SPSS for analysis.

3. Results

3.1. Study subjects and response

During 1961–1994, 171 individuals with cervical SCI fromdiving were identified by hospitals; 8 were deceased, including5 injured during 1961–1970 and 2 in 1971–1980. The aver-age number of cases per year during 1961–1994 was 4.8, anannual incidence of 0.75 per million population at the two hos-pitals. For 1995–2004, the average number per year was 4.0,an annual incidence of 0.53 per million. Of the 163 victimsalive during the first part of the study in 1996, 68 (42%) par-ticipated, and in 2004–2005, 21 of 40 eligible patients (52%)took part. Hence, total subjects were 89 and overall responserate excluding the deceased was 44% (89/203). Complete infor-mation was available for 87; two questionnaires were lost. Byyear of SCI, the final sample included: 5 from 1961–1970, 18from 1971–1980, 24 from 1981–1990, 32 from 1991–2000, and8 from 2001–2004.

3.2. Personal risk factors

Study participants were predominantly male (Table 2). Theyoungest was 12 years old when injured; 85% were <35 and95% <45. While 56% had taken swimming training, only 33%had training in water safety and only 37% had been aware ofthe risk of SCI associated with head-first diving prior to injury.Most had been swimming at least weekly during summer. While31% had at least some university education, only 13% of parentsdid. As for drugs, alcohol consumption at the time of injury wasself-reported by 47% and other drugs by 3%.

Author's personal copy

790 P. Barss et al. / Accident Analysis and Prevention 40 (2008) 787–797

Table 2Personal risk factors for victims of SCI from diving Quebec, Canada 1961–2004(n = 89)

Risk factor n %

Male sex 82 92

Age in years at time of SCI0–14 7 815–24 47 5225–34 22 2535–44 9 10≥45 4 5

Education in years at time of SCISCI victim

≤6 – primary school or less 1 17–11 – high school or less 36 4112–13 – community college 23 2614–16 – some university 19 22>16 – post-graduate 8 9

Victim’s parents≤6 26 307–11 – high school or less 29 3312–13 – community college 17 2014–16 – university 7 8>16 – post-graduate 4 5

Training prior to SCISwimming and water safety 29 33Swimming only 20 23None 38 44

Knowledge of risk of SCI from diving prior to SCI 33 37

Frequency of swimming during summer prior to SCIDaily 26 30Once or twice per week 37 44Once or twice per month 16 18Once or twice per summer 8 8

Self-reported consumption of alcohol at time of SCI 42 47Self-reported consumption of other drug 3 3

3.3. Environmental risk factors

About half of SCIs happened in pools and half in naturalbodies of water, mainly in rural locations (Table 3). The envi-ronment was new for 42% of victims, whose dive was their firstat the site. Darkness was reported in 30% of incidents.

Table 3Environmental risk factors for SCI from diving Quebec, Canada 1961–2004(n = 89)

Risk factor n %

Type of body of waterSwimming pool 45 49Natural bodies of water 44 51

Rural location 57 65

Time of dayDay 63 70Evening/dusk 12 14Night/dark 14 16

First dive at site by SCI victim 37 42

Table 4Environmental risk factors for SCI from diving in natural sites Quebec, Canada1961–2004 (n = 44)

Risk factor n %

Type of body of waterLake or pond 28 63River 9 20Ocean 3 7Other 4 9

Site of diveDock/wharf 16 36Shoreline* 9 20Boat 5 11Diving board 4 9Bridge 4 9Other 6 14

Poor visibility of bottom** 30 70Depth ≤1.4m at site of dive 34 79

Note: (*) Includes one person who dove off a cliff; (**) two victims could notrecall visibility.

Lakes were the most frequent natural body of water for SCIs,and docks or wharfs the most frequent site of dives into naturalbodies (Table 4). Poor visibility of the bottom was noted in 70%of cases. 79% of dives took place in water ≤1.4 m deep.

3.4. Equipment factors

Equipment factors were mainly pertinent for pool incidents(Table 5). Above-ground pools accounted for 57%, and 77% ofthem had a terrace. While 51% of dives originated from the pooledge, 16% were from a diving board and 9% from high locationssuch as a roof or second-floor balcony. Of considerable concern,three of the victims reported diving from diving boards wherepool depth was 2.74 m (9 ft) or deeper. The most frequent siteof impact was the up-slope between deep and shallow ends.Most SCIs occurred in single-unit home pools, and most at oneowned by friends rather than at home. 76% of pool victims saidthe bottom was visible, which contrasts with low visibility atnatural sites. In 52%, depth was ≤1.4 m at site of impact. Visibleindicators prohibiting diving or warning of depth were absentfrom all but a few pools. There were no significant trends in theproportion of SCIs that occurred in pools during the period ofthe study.

4. Discussion

Diving SCIs are an enormous burden for patients and theirfamilies, and very costly for taxpayers, since most victims suf-fer tetraplegia, mainly complete. In the United States, lifetimecosts for a 25 year-old with high tetraplegia average $US2.8million ($C3.1 m), compared with $US1.6 m for a 50 year-old(NSCISC, 2005, 2006). The greatest costs are incurred in thefirst year after injury, averaging $US0.7 m for high tetraplegia.During 1999–2004, the average annual number of new cervicalSCIs from diving was 12 in Quebec (Danielle Forest, Ministry ofHealth of Quebec, unpublished personal communication, 2004).

Author's personal copy

P. Barss et al. / Accident Analysis and Prevention 40 (2008) 787–797 791

Table 5Equipment risk factors for SCI from diving in swimming pools Quebec, Canada1961–2004 (n = 45)

Risk factor n %

Type of swimming poolAbove ground 26 57

With terrace 20 77Without terrace 6 33

In ground 19 43

Site of divePool edge 23 51Diving board 7 16Ladder 4 9Roof 2 4Other* 9 20

Site of impact for in-ground poolsUp-slope of bottom 12 63Flat bottom 4 21Diving board 1 5Security rope with floats 1 5Circular life ring, soft plastic 1 5

Ownership of poolPrivate

Single-unit home 39 87Apartment 1 2Hotel 1 2

Public 4 9

Ownership of single-unit home poolsFriends 24 62Self 6 15Parents 4 10Other 5 13

Depth ≤1.4 m at site of impact 23 52

Presence of indicator prohibiting divingAbove-ground pools** 2 4In-ground pools 1 11

Presence of depth indicatorAbove-ground pools 0 0In-ground pools 5 26

Note: (*) Other included 1 window, 1 second-floor balcony, 1 guardrail; (**)two persons could not remember if indicator was present.

If injuries remain unchecked, and one assumes expenses approx-imate those in the United States, they will cost the province about$C300 m per decade.

Since economic costs and suffering are extremely high fordiving SCIs, and all should be preventable, even a single casemust be considered unacceptable. It is essential for researchersand policy makers to introduce and evaluate interventions. It isjustifiable to dedicate at least a proportion of the millions thatsuch injuries cost annually to research and prevention, providedthey are evaluated and proven effective. Encouraging measuresthat shift the burden of funding research and prevention of divingSCIs at home pools from governments to pool vendors, or to acoalition of pool manufacturers and vendors, insurance compa-nies, water safety organizations, and government is desirablesince this consumer product, the pool, is the single greatestsource of diving SCI in Quebec, and probably elsewhere inCanada.

Risk factors for injury are frequently studied using variousinjury matrices devised by Haddon (Haddon, 1980, 1968), whichevolved from the classic epidemiologic triad of host, agent andenvironment. As we use it, the matrix includes personal, equip-ment, and environmental factors on one axis and the pre-event,event, and post-event phases of an injury incident on the other(Barss et al., 1998). Since much of Haddon’s work involvedtraffic safety, the equipment element was denoted by the morespecific term vehicle factors, or vector, but not by the etiologi-cal agent, which is for diving kinetic energy and for drowningblockage of energy processes.

4.1. Equipment and environmental risk factors for divingSCI

In the context of pool safety, equipment can be causal as inpools that are too short or shallow for safe diving and protectiveas with longer deeper pools providing safer diving or automati-cally closing and latching gates that avert drowning by excludingsmall children. Since it is mainly 1–4 year olds who drown inhome pools, making pools deeper will probably not change thatrisk – only automatic gates are likely to do so. Barriers may alsohelp to alert divers and all pool users that they have entered apotentially hazardous zone, and also to avert diving into at leastcertain hazardous natural sites.

Equipment factors are highly pertinent to prevention of divingSCIs, since in Quebec at the time of the research half occurred ina consumer product, swimming pools. Current preventive factorsfor pools act mainly in the pre-event phase. A fundamental issueis whether most standard pools are safe for diving under anyconditions, especially for the average recreational user. Currentdesigns are generally planned with a view to aesthetics, togetherwith limitations of space, depth, and cost, rather than for safetyto prevent diving SCIs and drownings. Even children undergoingdiving training at recommended minimum depths achieved headvelocities capable of causing cervical spine injury to an adult(Blanksby et al., 1996, 1997; Blitvich et al., 2003a,b). Swimmingpool safety, including prevention of both drownings and divingSCIs, is an important issue for Quebec. During 1991–2000 47%of 121 pool drownings of 1–4-year-old children in Canada werein this province, which has 24% of the country’s population butabout half of the pools (Barss, 2006).

In our survey, above-ground pools predominated. Most werefitted with an elevated terrace or patio at water level – such sur-faces facilitate diving as well as access by toddlers from adjacentliving spaces of the home. These pools are very hazardous fordiving because they are too shallow for deep dives and of insuf-ficient length for shallow-entry ones; exposure to risk is highsince they are the most frequent variety in Quebec. Evidentlythere is an alarming lack of awareness among young peopleregarding the danger of such pools. It was astounding that indi-viduals dove from sites such as roofs, windows, and second-floorbalconies with or without alcohol: such events demonstrate thatpool users have not learned the hazards of diving headfirst. Sim-ilar behaviour was also reported from the United States threedecades ago (Green et al., 1980).

Author's personal copy

792 P. Barss et al. / Accident Analysis and Prevention 40 (2008) 787–797

As several SCIs occurred during dives from a diving boardin both our series and two earlier studies from the United King-dom (Frankel et al., 1980) and the United States (Green et al.,1980), evidently boards are installed on pools with deep endsthat are actually neither sufficiently deep nor long for diving.The up-slope, “quad wall” or “spinal wall” (Blanksby et al.,1997, 1996; Zader, 1998), of so-called hopper pools is the pointof impact for most diving SCIs. Hence, even for in-ground poolsit is doubtful that current designs are adequate in depth or lengthfor safe diving, especially for adult males. Many men are talland heavy, so the kinetic energy of impact onto a pool up-slopeis high. On the basis of experimental studies published as earlyas 1975, it was recommended that one should not dive into waterless than twice one’s height (Albrand and Walter, 1975). If wecompare the necessary depth for 1.22 metre (4 ft) and 1.83 m(6 ft) tall individuals, the difference is 1.22 m. Few, if any, homepools meet this requirement of 3.7 m depth for a moderatelytall adult male. This early research-based recommendation isworth remembering during assessment of old and new modelregulations for depth and length of pools.

It is also essential to consider depth at the location of maxi-mum dive depth since the deepest point in the dive is at a distancefrom the point of entry, and pool depth is more relevant at thispoint than where entry occurs. If the deep end is short, a divingboard extends over it for a metre, and the diver leaves it at anangle, actual depth at entry will be much less than the maximumat the deep end.

Experimental research (Blitvich et al., 1999) showed that indives from the pool deck, the distance covered to maximumdepth averaged 3.42 m with a maximum of 5.75. Dives fromcompetitive blocks at a height of 0.75 m averaged 4.02 m with amaximum of 5.96. If we add a metre of diving board extension tothese maximums, evidently maximum depth could be reachedat a distance of up to about 7 m (23 ft), from the edge of thedeep end of a pool, or 6 m from the tip of the diving board. Atypical design obtained, with difficulty, from a vendor for in-ground home pools in Quebec showed a total length of only8.8 m. Hence, a diver might reach maximum depth at a point upto 80% along the length of such a pool.

It is probably too ambitious for most home pools to bedesigned for both safe diving and swimming. In response toa million dollar quad wall SCI jury verdict in 1970, researchwas commissioned in the early 1970s by the United Statespool industry’s former national trade association, the NationalPool and Spa Institute (NSPI). The unpublished, indeed sup-pressed, results showed that the cheap, “hopper-bottom” poolsdesigned to fit an average residential backyard were too smallfor safety (Zader, 1998). The deepest portion constituted as lit-tle as 4% of the surface area. Exactly as we suspected fromthe present interview research in Quebec together with obser-vation of plans for new in-ground pools being marketed therein the late 1990s, the experimental research reported to NSPIin 1974 had demonstrated that water between the tip of div-ing boards and the quad wall was insufficient to deceleratea tall heavy athletic male. After losing a $US8 million set-tlement plus interest lawsuit and appeal to a teenager whosustained tetraplegia from an SCI in a hopper-bottom pool

in 1998, NSPI immediately declared bankruptcy, became theInternational Aquatics Foundation (IAF), and no longer pub-lishes norms (Zader, 1998). Hundreds if not thousands ofdiving SCIs in Canada, not to mention the United States,could probably have been averted if the NSPI’s research, con-ducted at the Massachusetts Institute of Technology’s pool, hadbeen immediately published and new safety standards insti-gated.

It is noteworthy that in the city of Toronto in Canada’s largestprovince, Ontario, research showed that during 1948–1973, 11%of 358 SCIs were from diving, but that only 1 of 36 diving SCIsoccurred in a pool, with all others in lakes in this region of cot-tage country (Tator et al., 1981). The authors went on to note aremarkable trend: during the subsequent years 1974–1979, halfof the victims of diving SCI in their acute unit had been injuredin pools. The paper recommended educational programmes andwarning signs and concluded as follows: “Reckless diving mustbe considered as one of summer’s main hazards.” Other publi-cations by the same author in Toronto confirmed the importanceof diving as the source of 11–12% of all SCIs and 52–70% ofsport/recreational SCI (sport/recreational cases represented 18%of all SCIs), but since most incidents had occurred in lakes, rec-ommendations focused on personal factors and warning signsrather than pool factors (Tator and Edmonds, 1979; Tator etal., 1993). A more recent study, 1997–2001, from another lessmetropolitan region of the province showed only 9% of all SCIfrom sport/recreation (Pickett et al., 2006). The difference couldbe due to a different urban/rural mix or to a wider trend towardsgreater safety in sport.

In retrospect, it appears likely, but deserves further study, thatthe reason for the sudden change in the epidemiology of divingSCI in Toronto was the introduction of a new hazardous product.As hopper pools had proliferated across the United States, so didquad wall SCIs. NSPI’s attorney, William Ginsburg, helped cre-ate a product liability committee to devise a defence for membersagainst lawsuits from diving SCI. Prior to their big loss in 1998his firm successfully defended hundreds of diving injury casesusing the strategy of always blaming the diver (Zader, 1998).Indeed, since the incidence of diving injury in Canada and theUnited States has been about double that in Europe in recentdecades (Table 1), a possible cause of this intercontinental geo-graphic variability could have been higher exposure to unsafehome pools. Supporting this, there was some improvement indiving SCIs in the United States in the late 1990’s comparedwith earlier years (DeVivo, 2003).

There are unfortunately no model provincial regulations inQuebec for in-ground home swimming pools. Only public poolsmust conform to such norms, included in Le reglement sur lasecurite dans les bains publics which governs depth of waterat the end of the diving board (plummet) and other issues (GQ,2007). Depth at plummet is fixed at 2.7 m for a diving board of0.5 m or less above the water, 3.0 m for a board more than 0.5 andless than 1.0 m above the water, for a half-circle of 3.0 m fromthe end of the board. Such a norm would be expected to reducethe risk of striking the up-slope but in view of the evidence citedearlier and other norms below a depth greater than 3 m, extending5–6 m beyond the plummet, would be more appropriate.

Author's personal copy

P. Barss et al. / Accident Analysis and Prevention 40 (2008) 787–797 793

Model regulations for public or other pools where divingis permitted could not be found on the internet for CanadianStandards (CSA) or for individual provinces, with the exceptionof British Columbia, which for a board at deck level, requiresa depth of only 2.4 m (8 ft) at the plummet, 2.7 m (9 ft) at thedeepest point, and a distance from the plummet to the beginningof the upslope of only 2.4 m (8 ft) (GBC, 2007). The FederationInternationale de Natation – International Swimming Federation(FINA) – recommends 3.5 m (11.5 ft) depth at the plummet and3.4 m (11.2 ft) depth for at least 5.0 m (16.4 ft) from the plummetof a one-metre springboard (FINA, 2007). FINA standards ascited in a 1980 paper on SCI (Frankel et al., 1980) were lessdemanding, and required a depth at the plummet for recreationaldiving of only 2.6 m (8.5 ft), with this distance to be maintainedforward for only 3.0 m (9.8 ft).

In a study from the United Kingdom in the 1970s (Frankel etal., 1980), 35% of SCIs from diving had occurred in pools, ofwhich 46% occurred at the shallow end, but 21% at the deep endfrom the diving board. In another study from the United Statesaround the same time, 53% of diving SCIs in pools occurredin the shallow ends of in-ground pools or into above-groundpools, but 15% involved dives from boards (Green et al., 1980).The more recent FINA norms are clearly an improvement andmight have averted such SCIs if applied to all pools with div-ing boards, but whether they are adequate for pools used byuntrained recreational divers merits further study. Nonetheless,they do come close to meeting the 1975 experimentally basedrecommendations described above (Albrand and Walter, 1975).

The absence of norms for residential pools facilitates sale andinstallation of pools that are neither sufficiently deep nor withadequate distance between the end of the board and the up-slope.Hence, in usual short home pools of ≤9 m (30 ft) long, the depthwhere a diver’s head reaches the up-slope will be much shallowerthan at the middle of the deep end; even the deep end is as shallowas 2.4 m (8 ft) in some pools. Unless a pool is completely filled,actual water depth will be less than pool depth and the distancefrom the tip of the diving board or pool edge to the surface,and therefore acceleration and the resulting kinetic energy to bedissipated by the water, will be greater. Since the kinetic energytransferred to the cervical spine in striking the head directlyagainst a steep up-slope would be considerably greater than aglancing blow off a shallow bottom, gradual gradients ratherthan a sudden change could be safer since some untrained poolusers will inevitably dive in.

Although it is difficult to imagine it could compensate forinadequate pool dimensions, an event-phase protective equip-ment factor could be an energy-absorbing surface for the deepend and pool up-slope. Energy absorbing surfaces are alreadyused in many consumer products such as playground surfacesand various parts of automobiles where a head or other bodypart may impact; experimental studies would be necessary todetermine the effectiveness of such an approach.

Protective pre-event phase equipment includes signs to indi-cate depth and alert users that a pool is unsafe for diving. Suchsigns were uncommon at pools in this study. During a visit to alarge pool store, we observed a tiny warning sign on the rim of anabove-ground pool that would have been illegible to someone

standing on a terrace level with its edge. Evaluation of vari-ous signs to verify whether typical users such as young malesunfamiliar with the pool actually noticed and understood themduring day and night conditions – and modified their behaviour– is essential. Since our results show that the pool bottom isusually visible, large fluorescent warnings and depth indicatorsat this site might be obvious to most potential divers. Researchhas shown that typical no-diving signs are seldom noticed andeven when they are may actually provoke unsafe behavioursuch as diving into shallow water (Goldhaber and deTurck,1988). Hence, research-based guidelines (Wogalter et al., 2002)should be followed and safety warning signs evaluated objec-tively among the appropriate target group of young males. Thedifficulty in designing effective signs lends further support to theneed for pools that are also designed to be as safe as possible,on the basis of sound transparent research.

As for SCIs in natural bodies of water, the main site of diveswas docks or wharfs, both of which are modifiable products.Since most dives were into shallow water, barriers should beinstalled at hazardous locations where people might be temptedto dive, or dock areas dredged to provide a safer depth. Barriersat such locations, and at pools, could be designed in such amanner as to alert people that they have moved into an area ofincreased risk. Warning signs might be useful, bearing in mindthe requirements and limitations of such devices (Goldhaber anddeTurck, 1988; Wogalter et al., 2002).

Visibility is an environmental risk factor, and poor visibilityof the bottom was reported for SCIs from most dives at naturalsites. For SCIs at both pools and natural sites, 30% occurred atdusk or after dark; only a few pools were well-lit. During theday, pool bottoms were generally visible, but this did not appearto have deterred the victims. It could be that prominent depthmarkers on the bottom and sides of pools are necessary for validperception of depth, even when the bottom is visible. The impactof colours used for pool bottoms on depth perception needs tobe assessed. Guidelines for colour, size, and placement of depthmarkers and for lighting of pools are included in regulations forpublic pools in Quebec (GQ, 2007), and might be useful forhome pools if they are evidence-based.

4.2. Personal risk factors for diving SCI

As for personal or host factors, in our study, as in others,males 15–44-years-old were the main risk group (NSCISC,2005, 2006; Djerrari, 2000; O’Connor, 2002; RCIS, 2006;Griffiths, 1980; Aito et al., 2005). Most modifiable host factorspertain to the pre-event phase. Although most victims were fre-quent swimmers, few reported that they were aware of the hazardof diving headfirst. This suggests that although half had receivedswimming and one-third water-safety training, it was inadequatefor prevention of diving SCIs. Alcohol is a risk factor for manyinjuries, and diving SCIs are no exception, with consumptionprior to the incident reported by half; similar results have beenfound elsewhere (Blanksby et al., 1997). An experimental studyshowed progressive deterioration in performance of recreationaldivers beginning at 40 mg% blood alcohol (Perrine et al., 1994),half the legal limit for driving a car in Canada. Divers were

Author's personal copy

794 P. Barss et al. / Accident Analysis and Prevention 40 (2008) 787–797

unaware of their poor performance and increased risk of injury.Furthermore, a positive correlation between severity of SCI andblood alcohol level has been reported (Forchheimer et al., 2005).

While feet-first entry is to be preferred, and should be stronglyrecommended in home pools, many recreational swimmers dowant to and will dive in certain situations. Hence, training in thesafest diving techniques should be covered. A study of recre-ational swimmers found that in 18% of dives, the swimmerpulled his/her arms backward in a breaststroke motion leavinghead and neck unprotected (Blitvich, 2006). Variables of a divethat affect risk include depth of dive, flight distance, angle ofentry, and velocity at maximum depth (Blitvich et al., 1999).Variables of technique include locking hands together to pre-vent them being forced apart by water pressure, locking armstogether against the head to lock the head, and steering-up skillsto minimize depth and distance at depth. A study of diving train-ing in Australia showed that six 10-min sessions were sufficientto provide recreational swimmers with skills to make shallowdives and to lock the arms onto the head; skills were retained atleast 20 months (Blitvich et al., 2000, 2003a,b).

4.3. Limitations

Some limitations of this study should be noted. Despite upto four efforts to contact all patients, our response rate wasrelatively low at 44% of victims believed alive. This may, how-ever, reflect the retrospective study period necessary to recruitsufficient patients for meaningful study. Furthermore, limitingthe study to two rehabilitation hospitals could have excludedsome subjects treated at general or paediatric facilities. Indeed,

the incidence at the two hospitals was much less than reportedby MedEcho, as Table 1 evidences. There may have been a biasin type of individuals lost to follow-up, including more severeinjuries or older individuals. We did verify trends in the propor-tion of pools involved and did not detect significant change in thisvariable during the study period. In addition, long recall periodsmay have affected validity of some responses: participants mighthave underreported alcohol, and we did not assess diving relatedinjuries or fatalities other than hospitalization for cervical SCI.We had originally planned to compare pools where diving SCIoccurred with control pools, and victims with control divers, butwere unable to do this; it could be useful for future studies. Bet-ter exposure measures such as estimates of the number of divesper year into pools of different depths and the numbers of poolsof different depths might also prove worthwhile. It would havebeen useful to inquire about factors such as whether victimshad their arms out in front of them, locked or loose and whetherwater safety and swimming training had included details aboutkey elements of diving safety. Since SCI represents only about20% of all diving/jumping into water injuries in Quebec andelsewhere in Canada, investigation of other injuries would alsobe beneficial (Djerrari, 2000). Unfortunately, external causecodes in ICD 9 and ICD 10 classify diving and jumping together,complicating analysis (World Health Organization, 1978, 1992)

4.4. Recommendations

Table 6 summarises recommendations for prevention of SCIfrom diving, and is followed by more detailed consideration.

Table 6Recommended interventions to prevent SCI from diving

Equipment risk factorsModel consumer protection regulations for home and other swimming pools:• Establish province-wide, nation-wide, and international research-based norms of diving safety design parameters for low-risk home, public pools, and other

pools.• Prohibit sale of diving boards for usual home pools, and any other pools that do not meet research-based criteria and norms of low-risk pools for diving.• Discourage sale/use/purchase of home pools that have a deep end combined with an up-slope.• Ensure that vendors are required to be properly trained and to train purchasers in pool safety, including the hazards of head-first entry.• Implement codes to include warning signs prohibiting diving, that are highly visible and proven to be effective among young males in all lighting conditions.• Include depth indicators in codes, certified visible in all lighting conditions.• Use municipal aerial surveillance with photographs to identify potentially risky pools, followed up with ground surveillance by inspectors, for both diving

SCIs and automatic gates to prevent child drowning

Personal risk factors• Implement research-based comprehensive swimming and water safety, including diving safety, programmes for all children and youth.• Incorporate water safety into swimming programs, including the hazards of headfirst entry and limitations of most pools, to ensure water competence

(Brenner et al., 2006).• Reach high-risk individuals, including male youth, by mandatory comprehensive evidence-based training in water competence by health curriculum or

physical education at schools.• Encourage feet-first entry into pools and natural sites.• Discourage diving in home pools and other pools that do not meet criteria of low-risk diving.

Teach three key elements to those who insist on diving:• Diving environment must be known to be reasonably safe, i.e., certified on the basis of safety criteria as low-risk for diving by experts.• Diving should be undertaken only by individuals trained in safer diving skills.• Alcohol must be completely avoided by all divers, since diving skills and awareness of risk deteriorate at even low blood alcohol levels.

Environmental risk factors• Mandate pool lighting that ensures the entire bottom of pool is clearly visible.• Ensure water sufficiently clear so that bottom is visible.

Author's personal copy

P. Barss et al. / Accident Analysis and Prevention 40 (2008) 787–797 795

The best chance for success in reaching the greatest num-ber of persons is probably via comprehensive evidence-basedswimming and water safety programmes. Programmes such asthose provided by organizations like Red Cross would preferablyreach all young people in communities across the country andincorporate training not easily forgotten. All organizations thatprovide diving safety teaching must ensure that training materi-als and instructors are regularly updated on the basis of the bestavailable research evidence.

To reach high-risk individuals schools could be required toinclude water safety and swimming training in their health orphysical education curriculum. All swimming programs shouldincorporate water safety to ensure water competence (Brenneret al., 2006), including teaching the hazards of headfirst div-ing. Regular publicity is also needed to emphasize that divingis an activity with a high potential for injury. Training of newpool owners in pool safety, including drowning prevention andwhether diving safely is feasible in their new pools, shouldbe obligatory. Vendors should perhaps also be responsible forensuring that the purchasers have received effective trainingprior to handing over a new pool installation to them.

For swimmers who insist upon diving, at least three key ele-ments for low-risk diving need to be taught. First, the divingenvironment must be known to be reasonably safe, i.e. assessedas meeting up-to-date safety design parameters. Few if any homepools meet this requirement, nor do many hotel pools and nat-ural sites. Second, since diving is a high-risk activity, it shouldonly be undertaken by individuals with training in safer divingskills. Third, because diving skills and awareness of risk dete-riorate measurably even at low blood alcohol concentrations,all including the experienced must avoid diving after alcoholconsumption.

As for pools, historically, most private in-ground pools were,and probably still are, built in Quebec and elsewhere accordingto unofficial norms 2.4 m (8 ft) deep suggested by the now-bankrupt American National Spa and Pool Institute (NSPI). Yet,a few years ago these “norms” were judged unsafe in a US court,as noted in Section 4.1 (Zader, 1998). A working study wasdone in Quebec in 2006 to evaluate the possibility of designingnorms for “safe” pools equipped with a diving board, l’Etudede faisabilite sur l’elaboration d’une norme pour les piscinesresidentielles equipees d’un tremplin (Rousseau and Langlais,2006). It was conducted by the Bureau de normalisation duQuebec (BNQ) at the request of the Societe de sauvetage, theMinistry of Health and Social Services, and the Ministry of Edu-cation, Leisure and Sport. The report is considered a workingdocument.

Nevertheless, since few home pools meet safety norms forpublic pools, since there are many more home than publicpools and their use is largely unsupervised, and since the con-sequences of a catastrophic diving SCI are the same wherever itoccurs, it may be safer to simply prohibit fitting of diving boardsand strongly discourage diving for home pools. An exceptioncould be made for home pools that meet or exceed internationalsafety design requirements for low-risk diving public pools,such as those of FINA (FINA, 2007). Furthermore, since manySCIs occur at a pronounced up-slope and some individuals will

inevitably dive into home pools, hopper-type pools should bebanned and only pools with a gradual up-slope accepted. Thiscould also help avoid drownings among waders who are non-swimmers. Similar considerations should apply to hotel andother pools.

All the foregoing leads us to suggest adoption of province-wide, nation-wide, and indeed international norms for privatepools similar to existing ones for public pools, providedthe norms for public pools are evidence-based. Such norms,as has been the case for automatic pool gates to preventchild drownings, may be resisted by pool vendors. Due tocosts of deeper and longer excavations and to space limita-tions, vendors tend to lobby for shallow in-ground pools withshort deep ends. Nevertheless, many now-standard safety mea-sures for other hazards were initially resisted by industry:examples include automatic protection for vehicle occupants,such as airbags, seatbelts, and intrusion-resistant frames.Some municipalities in Australia now use aerial surveil-lance with photographs to identify pools, followed up byinspectors who verify the presence of the appropriate safetygates and fences to protect small children from drowning.Municipal surveillance of pools should be comprehensivefor both diving SCIs and drowning. Hence sound provin-cial and federal norms of consumer protection, togetherwith municipal regulations and enforcement, are urgentlyrequired for this hazardous product. While norms shouldbe developed to protect untrained recreational divers, theyshould be complemented by universal water safety training askey elements of population-based prevention of water-relatedinjuries.

Competing and conflict of interest

None declared.Contributors: Peter Barss planned the initial study and the

protocol to obtain initial funding, supervised Hind Djerrari forher M.Sc. research, and prepared the final version of this paperin collaboration with other authors. Ms. Djerrari helped withcollecting and analyzing data and some interviews as part ofher thesis in Community Health in the Department of Socialand Preventive Medicine of Laval University. Clermont Dionne,Quebec Health Research Fund scholar, was a co-supervisor ofMs. Djerrari’s MSc and reviewed the final version of the paper.Bernard Leduc collaborated with writing up the study, helpedobtain part of the funding, and facilitated collaboration withhospitals. Yves Lepage helped with data analysis for part of thestudy.

Acknowledgements

We thank especially study participants for sharing detailsof their injuries and Dr. Pierre Proulx, formerly of the Insti-tut de readaptation de Montreal, for suggesting the research andhelping to obtain initial funding. M. Andre Senecal and his foun-dation were very supportive. Isabelle Masson and Dr. AlisonMacpherson did administrative coordination and epidemio-logic assistance, medical records departments helped locate and

Author's personal copy

796 P. Barss et al. / Accident Analysis and Prevention 40 (2008) 787–797

communicate with patients, Anna Cockerton helped with inter-viewing, and Sophie Lapointe with data entry. Funding was byFondation pour la recherche sur la moelle epiniere and Fonda-tion de l’Institut de readaptation de Montreal. Administrativesupport was provided for part of the study by Direction de lasante publique de Montreal-Centre, Ministere de la sante et desservices sociaux, and by the Research Institute, Montreal Gen-eral Hospital of McGill University Health Centre. Terri Everestreviewed the English of the final drafts. Dr. Peter Barss had fullaccess to all of the data in the study and takes responsibility forthe integrity of the data and the accuracy of the data analysis.

References

Aito, S., D’Andrea, M., Werhagen, L., 2005. Spinal cord injuries due to divingaccidents. Spinal Cord 43, 109–116.

Albrand, O.W., Walter, J., 1975. Underwater curves in relation to injuries fromdiving. Surg. Neurol. 4, 461.

Barss, P., 2006. Drowning and Other Water-Related Injury Fatalities inCanada: An Analysis of the Circumstances and Trends of Water-Related Fatalities in Canada in 1991–2000. The Canadian Red CrossSociety (also published in French), Ottawa, ON, p. 23. Available at:http://www.redcross.ca/cmslib/general/drowrep2006overview en.pdf.

Barss, P., Smith, G.S., Baker, S.P., Mohan, D., 1998. Injury Prevention: AnInternational Perspective. Epidemiology, Surveillance, & Policy. OxfordUniversity Press, New York, 12–25.

Blanksby, B.A., Wearne, F.K., Elliott, B.C., 1996. Safe depthsfor teaching children to dive. Aust. J. Sci. Med. Sport 28,79–85.

Blanksby, B.A., Wearne, F.K., Elliott, B.C., Blitvich, J.D., 1997. Aetiology andoccurrence of diving injuries. A review of diving safety. Sports Med. 23,228–246.

Blitvich, J., 2006. Section 5.17 Spinal Injuries: Prevention, Immobilisation andExtrication from the Aquatic Environment – 5.17.1 Prevention of SpinalInjuries. In: Bierens, J. (Ed.), Handbook on Drowning. Springer-Verlag,Heidelberg, pp. 289–291.

Blitvich, J.D., McElroy, G.K., Blanksby, B.A., Douglas, G.A., 1999. Character-istics of ‘low risk’ and ‘high risk’ dives by young adults: risk reduction inspinal cord injury. Spinal Cord 37, 553–559.

Blitvich, J.D., McElroy, G.K., Blanksby, B.A., 2000. Risk reduction in divingspinal cord injury: teaching safe diving skills. J. Sci. Med. Sport 3, 120–131.

Blitvich, J.D., McElroy, G.K., Blanksby, B.A., Parker, H.E., 2003a. Long-termretention of safe diving skills. J. Sci. Med. Sport 6, 348–354.

Blitvich, J.D., McElroy, G.K., Blanksby, B.A., 2003b. Retention of safe divingskills. J. Sci. Med. Sport 6, 155–165.

Brenner, R., Moran, K., Stallman, R., Gilchrist, J., McVan, J., Swimming Abili-ties, 2006. Water safety education, and drowning prevention. In: Bierens,J.J.L.M. (Ed.), Handbook on Drowning. Prevention Rescue Treatment.Springer-Verlag, Berlin, pp. 112–117.

DeVivo, M.J., 1997. Causes and costs of spinal cord injury in the United States.Spinal Cord 35, 809–813.

DeVivo, M.J., 2003. Epidemiology of spinal cord injury. In: Lin, V.W.(Ed.), Spinal Cord Medicine. Demos Medical Publishing, New York,pp. 79–85.

DeVivo, M.J., Sekar, P., 1997. Prevention of spinal cord injuries that occur inswimming pools. Spinal Cord 35, 509–515.

Djerrari, H., 2000. Circumstances of Spinal Cord Injuries from Diving inQuebec, Canada, 1961–1994 [M.Sc. Thesis]. Departement de sante com-munautaire, Universite Laval, Quebec, Canada.

Federation Internationale de Natation (FINA) – International Swimming Fed-eration. Rules and Regulations – Facilities Rules: FR5.3 Dimensions forDiving Facilities. Website consulted 22 August 2007. Available at URL:http://www.fina.org/rules/english/facilities.php.

Forchheimer, M., Cunningham, R.M., Gater, D.R., Maio, R.F., 2005. The rela-tionship of blood alcohol concentration to impairment severity in spinal cordinjury. J. Spinal Cord Med. 28, 303–307.

Frankel, H.L., Montero, F.A., Penny, P.T., 1980. Spinal cord injuries due todiving. Paraplegia 18, 118–122.

Government of British Columbia. Health Act Swimming Pool, Spray Pool,and Wading Pool Regulations, B.C. Reg. 289/72, O.C. 4190/72 (includesamendments up to B.C. Reg. 451/2003), Part 4 Pool Construction: Item21 Requirements for Diving, p. 8, and Appendix C, pp. 1–2. Websiteconsulted 21 August 2007. Available at URL: http://www.qp.gov.bc.ca/statreg/reg/H/Health/Health289 72/289 72.htm#section21.

Goldhaber, G.M., deTurck, M.A., 1988. Effectiveness of warning signs: genderand familiarity effects. J. Products Liability 11, 271–284.

Gouvernement du Quebec. Reglement sur la securite dans les bains publics –Loi sur la securite dans les edifices publics (L.R.Q., c. S-3, a. 39) Derniereversion disponible, incluant la Gazette officielle du 25 juillet 2007, consulted23 August, 2007, Section 2 Piscines, articles 11, 12, 15, 21, available at URL:http://www2.publicationsduquebec.gouv.qc.ca/dynamicSearch/telecharge.php?type=2&file=/S 3/S3R3.html.

Green, B.A., Gabrielsen, M.A., Hall, W.J., O’Heir, J., 1980. Analysis of swim-ming pool accidents resulting in spinal cord injury. Paraplegia 18, 94–100.

Griffiths, E.R., 1980. Spinal injuries from swimming and diving treated inthe spinal department of Royal Perth Rehabilitation Hospital: 1956–1978.Paraplegia 18, 105–117.

Haddon, W., 1968. The changing approach to the epidemiology, prevention, andamelioration of trauma: the transition to approaches etiologically rather thandescriptively based. Am. J. Publ. Health 58, 1431–1438.

Haddon, W., 1980. Advances in the epidemiology of injuries as a basis for publicpolicy. Publ. Health Rep. 95, 241–411.

International Campaign for cures of spinal cord injury paralysis. GlobalSummary of Spinal Cord Injury, Incidence and Economic Impact.ICCP March 2001 (Revised July 2004) Available at: http://www.campaignforcure.org/globalsum.htm.

Karacan, I, Koyuncu, H., Pekel, O., Sumbulo glu, G., Kırnap, M., Dursun, H.,Kalkan, H., Cengiz, A., Yalınkılic, A., Unalan, H.I., Nas, K., Orkun, S.,Tekeog, I., 2000. Traumatic spinal cord injuries in Turkey: a nation-wideepidemiological study. Spinal Cord 38, 697–701.

Kiwerski, J.E., 1993. The causes, sequelae and attempts at prevention of cervicalspine injuries in Poland. Paraplegia 31, 527–533.

National Spinal Cord Injury Statistical Center. Annual Statistical Report forthe Model Spinal Cord Injury Care Systems, 2005. Birmingham, Univer-sity of Alabama, p. 69, 71, 132 (pages change with updates). Available at:http://images.main.uab.edu/spinalcord/pdffiles/facts05.pdf.

National Spinal Cord Injury Statistical Center. Facts and figures at aglance – June, 2006. Birmingham, University of Alabama. Available at:http://www.spinalcord.uab.edu/show.asp?durki=21446.

O’Connor, P., 2002. Spinal Cord Injury, Australia, 1999–2000. AustralianInstitute of Health and Welfare, Injury Research and Statistics Series,Number 10, AIHW cat no. INJCAT 40. Canberra, Australia. Available at:http://www.nisu.flinders.edu.au/pubs/reports/2001/injcat40.php.

Parliamentary Assembly, Council of Europe, 2002. Towards concerted effortsfor treating and curing spinal cord injury [Report]. Social, Healthand Family Affairs Committee. Rapporteur: M Ouzky. Available at:http://assembly.coe.int/Documents/WorkingDocs/doc02/EDOC9401.htm.

Perrine, M.W., Mundt, J.C., Weiner, R.I., 1994. When alcohol and water don’tmix: diving under the influence. J. Stud. Alcohol 55, 517–524.

Pickett, G.E., Campos-Benitez, M., Keller, J.L., Duggal, N., 2006. Epidemiologyof spinal cord injury in Canada. Spine 31, 799–805.

Research Centre for Injury Studies, 2006. Bulletin 22 – Factors Associatedwith the SCI Event, 1998–1999. Flinders University. Adelaide, Australia.Available at: http://www.nisu.flinders.edu.au/pubs/bulletin22/bulletin22-Factors.html.

Rousseau, J., Langlais, D., 2006. Etude de faisabilite sur l’elaboration d’unenorme pour les piscines residentielles equipees d’un tremplin. Bureau denormalisation du Quebec, Quebec, Canada, pp. 1–45.

Schwarz, N., Sim, E., Nestinger, K., 2001. Injuries of the thoracic vertebrae inhead-first dive into water. Unfallchirurg 104, 300–302.

Author's personal copy

P. Barss et al. / Accident Analysis and Prevention 40 (2008) 787–797 797

Stone, R.S., 2003. A rationale for rating pools with diving boards.(Arthur D. Little Study No. 4). Cambridge, MA: Arthur D. Little Inc.,1981. Cited in: Blitvich, J.D., McElroy, G.K., Blanksby, B.A., Parker,H.E. Long-term retention of safe diving skills. J. Sci. Med. Sport 6,348–354.

Tator, C.H., Edmonds, V.E., 1979. Acute spinal cord injury: analysis of epidemi-ologic factors. Can. J. Surg. 22, 575–578.

Tator, C.H., Edmonds, V.E., New, M.L., 1981. Diving: a frequent and potentiallypreventable cause of spinal cord injury. CMAJ 124, 1323–1324.

Tator, C.H., Duncan, E.G., Edmonds, V.E., Lapczak, L.I., Andrews, D.F., 1993.Changes in epidemiology of acute spinal cord injury from 1947 to 1981.Surg. Neurol. 40, 207–215.

Wogalter, M.S., Conzola, V.C., Smith-Jackson, T.L., 2002. Research-basedguidelines for warning design and evaluation. Appl. Ergonom. 33, 219–230.

World Health Organization, 1978. Manual of the International Classificationof Diseases, Injuries, and Causes of Death. Ninth Revision, vols. I and II.WHO, Geneva.

World Health Organization, 1992. International Statistical Classification of Dis-eases and Related Health Problems. Tenth Revision, vol. I. WHO, Geneva,p. 1060.

Zader, F. Industry Trade Association Hits Bottom. Washington StateTrial Lawyers Association. Trial News, November 1998, p. 1–8.Available at: http://www.pypfirm.com/pypwebpdfs/Ind%20Trade%20Assn%20Hits%20Bottom.pdf.