| 1. |
- Jonsson, Bertil, 1956-
(författare)
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Interaction between humans and car seats : studies of occupant seat adjustment, posture, position, and real world neck injuries in rear-end impacts
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: The latest generation of rear-end whiplash protection systems, as found in the WHIPS Volvo and SAHR Saab, have reduced injury rates by almost 50% in comparison with the previous generation of seat/head restraint systems. Occupant behaviour, such as seated posture and seat adjustment settings, may affect the injury risk. Method: Five studies were conducted. Studie I was an injury outcome study based on insurance data. Studies II-IV investigated seat adjustment, occupant backset, and cervical retraction for drivers and occupants in different postures and positions in the car, during stationary and driving conditions. Study V compared the occupant data from studies II and III with a vehicle testing tool, the BioRID dummy, using the protocols of the ISO, RCAR, and the RCAR-IIWPG. Results: Female drivers and passengers had a threefold increased risk for medically-impairing neck injury in rear-end impacts, compared to males. Driver position had a double risk compared with front passenger seat position. Female drivers adjusted the driver seat differently to male drivers; they sat higher and closer to the steering wheel and with more upright back support. The volunteers also adjusted their seat differently to the ISO, RCAR, and RCAR-IIWPG protocol settings; both sexes sat further away from the steering wheel, and seat back angle was more upright then in the protocols. In stationary cars, backset was highest in the rear seat position and lowest in the front passenger seat position. Males had a larger backset than females. Cervical retraction decreased and backset increased for both sexes when posture changed from self-selected posture to a slouched posture. The BioRID II dummy was found to represent 96th percentile female in stature, and a 69th percentile female in weight in the volunteer group. Conclusions: Risks in car rear-end impacts differ by sex and seated position. This thesis indicates the need for a 50th percentile female BioRID dummy and re-evaluation of the ISO, RCAR, and RCAR-IIWPG protocols, and further development of new safety systems to protect occupants in rear-end impacts.
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| 2. |
- Ahlm, Kristin, 1956-
(författare)
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Traffic and drowning incidents with emphasis on the presence of alcohol and drugs
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Worldwide, fatal traffic injuries and drowning deaths are important problems. The aim of this thesis was to investigate the cirumstances of fatal and non-fatal traffic injuries and drowning deaths in Sweden including analysis of the presence of alcohol and drugs, which are considered to be major risk factors for these events. Data where obtained from the database of National Board of Forensic Medicine.In the first study, we investigated 420 passenger deaths from 372 crashes during 1993-1996. There were 594 drivers involved. In total, 21% of the drivers at fault were alcohol positive compared to 2% of drivers not at fault (p<0.001) (Paper I). During 2004-2007, crashes involving 56 fatally and 144 non-fatally injured drivers were investigated in a prospective study from Northern Sweden (Paper II). The drivers were alcohol positive in 38% and 21%, respectively. Psychoactive drugs were found in 7% and 13%, respectively. Benzodiazepines, opiates and antidepressants were the most frequent drugs found in drivers. Illict drugs were found 9% and 4% respectively, with tetrahydrocannabinol being the most frequent of these drugs (Paper II).We investigated 5,125 drowning deaths in Sweden during 1992-2009 (Paper III). The incidence decreased on average by about 2% each year (p<0.001). Unintentional drowning was most common (50%). Alcohol was found in 44% of unintentional, 24% of intentional, and 45% of undetermined drowning deaths. Psychoactive substances were detected in 40% and benzodiazepines were the most common substance. Illicit drugs were detected in 10%. Of all drowning deaths, a significantly higher proportion females commited suicide compared with males (55% vs. 21%, p<0.001). Suicidal drowning deaths (n=129) in Northern Sweden were studied further in detail (Paper IV). of these, 53% had been hospitalized due to a psychiatric diagnosis within five years prior to the suicide. Affective and psychotic disorders were the most common psychiatric diagnoses. Almost one third had performed a previous suicide attempt. One fourth had committed suicide after less than one week of discharge from hospital. Alochol was found in 16% and psychoactive drugs in 62% of these cases, respectively. In conclusion, alcohol and psychoactive drugs are commonly detected among injured drivers and drowning victims, and probably play a role in these events. Most of the individuals that tested positive for alcohol and high blood concentrations, indicating alochol dependence or abuse. This association warrants futher attention when planning future prevention.
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| 3. |
- Albertsson, Pontus, 1958-
(författare)
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Occupant casualties in bus and coach traffic : injury and crash mechanisms
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: The relevance of conducting this thesis is evident by the fact that bus and coach casualties have been “stubbornly stable” in Europe recent years and a need for investigating if a similar trend could be found in Sweden is therefore obvious. It was also important to add new knowledge to the bus and coach research in Sweden, since many areas were scarcely addressed. Aims: To describe bus and coach occupants’ injuries, crash and injury mechanisms generated in a traffic environment based on data from the medical sector. Additional aims were to investigate the injury reducing effect of a 3-point belt, the effect of cross-winds, and crucial factors in the emergency- and rescue response. Material and methods: Injury data analyses were based on a complete ten-year medical data set from a catchment-area with about 130,000 inhabitants. A number of crash studies with the scope in different crash phases were conducted by applying and elaborating the Haddon matrix as a framework. An additional framework, Protocol for Major Incidents was used in order to investi-gate the emergency- and rescue response to a severe coach crash. Results: Between the first and second five-year period, the incidence of injured in non-crash in-cidents was increased by 24%. In non-crash incidents, 54% were injured; 2/3 while alighting from a bus or coach. The pre-crash factor cross-wind, in addition to vehicle design, vehicle speed and road friction, was investigated in ten crashes. It was confirmed that cross-wind, in relation to vehicle speed and slippery road conditions, needs more attention. The importance of goods load-ing and passengers’ position in the bus, was indicated by the fact that a displacement of the cen-tre of mass rearwards with 10% increased the necessary coefficient of friction with, on average 45%, which in many cases corresponded to dry road conditions. Three Swedish rollover crashes were analysed with regard to the injury outcome, mechanisms and the possible injury reduction for occupants using a safety belt. A considerable increase in safety for occupants belted with 3-point belts was shown through limiting interior contacts, occupant interaction and the possibility of ejection. Crucial post-crash factors in the emergency- and rescue response showed that ordi-nary ways of working and equipment are not always useful and proper equipment for lifting a coach body is essential in the case of a rollover. Finally, the communication between the hospitals is important, and the telephone systems may be overloaded by calls from worried relatives and media. Conclusions: In non-crash events: Non-crash events constitute a majority of all bus and coach casualties with a high proportion of elderly female occupants among the MAIS 2+ injury cases. Boarding and, especially alighting causes many injuries to the lower extremities. In the pre-crash phase: Cross-winds do affect the safety of buses and coaches and requires more at-tention. Seat belt usage among bus and coach occupants has to be increased. In the crash phase: Rollover and ejection are the major causes behind serious and fatal injuries to bus and coach occupants, consequently, retentive glazing, pillars or rails need more attention. An upgrade from 2-point seat belts to 3-point seat belts yields an increase in the estimated injury re-duction from approximately 50% up to 80% for the MAIS 2+ casualties in a rollover crash. In the post-crash phase: In order to be able to lift a coach body proper equipment originated from experience and development is essential in a rescue operation of a crashed bus or coach. Fur-thermore, to improve the emergency response inside crashed coaches proper methods originated from experience need to be developed. Euro NBAP: Based on the results and conclusions generated in this thesis, a European New Bus and Coach Assessment Programme is suggested, which would provide bus and coach occupants with a assessment programme similar to the Euro NCAP.
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| 4. |
- Doohan, Isabelle, 1985-
(författare)
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Surviving a major bus crash : experiences from the crash and five years after
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Major road traffic crashes (RTCs) can have a significant impact on the survivors, their family, and their friends, as well as on emergency personnel, volunteers, and others involved. However, survivors’ perspectives are rare or missing in research on major RTCs in Sweden. A comprehensive understanding of the survivors and their experiences is also lacking. By studying what it is like to survive a major RTC, the care and support provided to survivors can be adapted and improved.The overall aim is to broaden the understanding of the short- and long-term consequences and experiences of surviving a major bus crash.Methods The contexts are two bus crashes that occurred in Sweden, in February 2007 and December 2014. In total, the participants are 110 out of the 112 survivors, and the data is collected through telephone interviews, official reports, and medical records at one month, three months, and five years after the crashes. Analysis methods include qualitative content analysis, descriptive statistics, thematic analysis, and mixed methods research analysis.Results One month after the crash, most of the survivors were experiencing minor or major physical and/or psychological stress in their everyday lives (Study I). Four main findings were identified regarding their experiences of immediate care (Study II): prehospital discomfort, lack of compassionate care, dissatisfaction with crisis support, and satisfactory initial care and support. The importance of compassion and being close to others was also highlighted. Five years after the bus crash in Rasbo (Study III), survivors were still struggling with physical injuries and mental problems. Other long-term consequences were a lasting sense of connectedness among fellow passengers, a gratitude for life, as well as feelings of distress in traffic, especially in regard to buses. The main findings from study IV indicated that injury severity did not seem to affect mental health, and that social aspects were important to the recovery process. There was an interconnection among survivors in which they seemed to be linked to each other’s recovery.Conclusion A strong need for short- and long-term social and psychological support in terms of compassion and community is evident in all the studies. The survivors ought to be acknowledged as capable and having the resources to contribute to their own and their fellow survivors’ recovery and health. There is a need for greater understanding of how different the survivors are, with each one of them having various physical, psychological, social, and existential needs.
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| 5. |
- Forsberg, Rebecca, 1976-
(författare)
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Train crashes : consequences for passengers
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Globally, and in Sweden, passenger railway transport is steadily increasing. Sweden has been relatively free from severe train crashes in the last decades, but the railway infrastructure is alarmingly worn and overburdened, which may be one reason for an increasing number of reported mishaps. Worldwide, major train crashes/disasters are a frequent cause of mass casualty incidents. Several shortcomings, especially within the crash and post-crash phases cause severe consequences for the passengers.Aim: To investigate the consequences of train crashes on passengers, focusing on factors of importance in the crash and post-crash phases. The specific aims are: (I) to identify the historical development and magnitude of passenger train disasters globally on various continents and countries, (II, III) to identify injury panorama and injury objects in two train crashes, (IV) to explore survivor´s experiences from a train crash, and (V) to explore their experiences of journalists and media coverage.Methods: Study I is a register study based on 529 railway disasters worldwide, whereas studies II-V are case studies from the two latest severe train crashes in Sweden (Nosaby and Kimstad). These studies are based on 73 and 21 passengers respectively. Studies I-III is essentially quantitative where descriptive statistics (I, III), multivariate analysis (III), and content analysis (II, III) are used. Studies II and III are also supplemented by semi-structured interviews. Studies IV and V are qualitative and the interviews (n=14, n=30) have been analyzed with qualitative content analysis. Study IV is also supplemented with quantitative data.Results: The number of railway disasters, fatalities, and non-fatally injured passengers has increased throughout the last hundred years - particularly during the last four decades (1970–2009) when 88% of all disasters occurred (I). Passengers in the first overturned carriage suffered most severe and lethal injuries (III). Internal structures such as tables, chairs, internal walls, as well as luggage, other passengers (II, III), glass (II), and wood pellets (III) induced many of the injuries. Those who traveled facing forward with a table in front of them, in carriages that did not overturn, were more likely to sustain injuries to their abdomen/pelvis than those without a table (III). Passengers who traveled rear facing had higher rates of whiplash injuries. Surviving a train crash was experienced as "living in a mode of existential threat". The long term consequences however were diverse for different persons (IV). All experienced that they had cheated death, but some became "shackled by history", whereas others overcame the "haunting of unforgettable memories." The centrality of others and the importance of reconstructing the turn of events were important when "dealing with the unthinkable". The media coverage were experienced as positive in the recovery process and the journalists were also perceived as helpful (V). By some the journalist’s nevertheless were also perceived as harmful or negligible, and the subsequent media coverage as either uncomfortable or insignificant.Conclusion: Despite extensive crash avoidance systems severe railway crashes still occur. Improved interior safety, as has been implemented in the automobile and aviation industries, would have an important reduction in injuries and facilitate evacuation. Being surrounded by family, friends, fellow passengers and participating in crash investigations, and experiencing descriptive media coverage were some crucial factors when dealing with the traumatic event and should be promoted.
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| 6. |
- Henriksson, Otto, 1976-
(författare)
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Protection against cold in prehospital trauma care
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Protection against cold is vitally important in prehospital trauma care to reduce heat loss and prevent body core cooling. Objectives: Evaluate the effect on cold stress and thermoregulation in volunteer subjects byutilising additional insulation on a spineboard (I). Determine thermal insulation properties of blankets and rescue bags in different wind conditions (II). Establish the utility of wet clothing removal or the addition of a vapour barrier by determining the effect on heat loss within different levels of insulation in cold and warm ambient temperatures (III) and evaluating the effect on cold stress and thermoregulation in volunteer subjects (IV). Methods: Aural canal temperature, sensation of shivering and cold discomfort was evaluated in volunteer subjects, immobilised on non-insulated (n=10) or insulated (n=9) spineboards in cold outdoor conditions (I). A thermal manikin was setup inside a climatic chamber and total resultant thermal insulation for the selected ensembles was determined in low, moderate and high wind conditions (II). Dry and wet heat loss and the effect of wet clothing removal or the addition of a vapour barrier was determined with the thermal manikin dressed in either dry, wet or no clothing; with or without a vapour barrier; and with three different levels of insulation in warm and cold ambient conditions (III). The effect on metabolic rate, oesophageal temperature, skin temperature, body heat storage, heart rate, and cold discomfort by wet clothing removal or the addition of a vapour barrier was evaluated in volunteer subjects (n=8), wearing wet clothing in a cold climatic chamber during four different insulation protocols in a cross-over design (IV). Results: Additional insulation on a spine board rendered a significant reduction of estimated shivering but there was no significant difference in aural canal temperature or cold discomfort (I). In low wind conditions, thermal insulation correlated to thickness of the insulation ensemble. In greater air velocities, thermal insulation was better preserved for ensembles that were windproof and resistant to the compressive effect of the wind (II). Wet clothing removal or the use of a vapour barrier reduced total heat loss by about one fourth in the cold environment and about one third in the warm environment (III). In cold stressed wet subjects, with limited insulation applied, wet clothing removal or the addition of a vapour barrier significantly reduced metabolic rate, increased skin rewarming rate, and improved total body heat storage but there was no significant difference in heart rate or oesophageal temperature cooling rate (IV). Similar effects on heat loss and cold stress was also achieved by increasing the insulation. Cold discomfort was significantly reduced with the addition of a vapour barrier and with an increased insulation but not with wet clothing removal. Conclusions: Additional insulation on a spine board might aid in reducing cold stress inprolonged transportations in a cold environment. In extended on scene durations, the use of a windproof and compression resistant outer cover is crucial to maintain adequate thermal insulation. In a sustained cold environment in which sufficient insulation is not available, wet clothing removal or the use of a vapour barrier might be considerably important reducing heat loss and relieving cold stress.
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| 7. |
- Lindquist, Mats, 1962-
(författare)
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Fatal car crash configurations and injury panorama : with special emphasis on the function of restraint system
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Most traffic safety research projects require accurate real world data which is collected in different databases around the world. This is especially important since the results of these projects form the basis for new crash test procedures and standards. In many of these databases the involvement of the frontal structures of the car in frontal crashes is coded by using the SAE J224 practice (Society of Automobile Engineers). There were indications that by using this practice the database would contain an overestimate of the car frontal structure involvement in real world crashes. One purpose of this thesis is therefore to develop a new method for real world crash investigations to better address this issue. One purpose was also to adopt this method in a data collection of fatal crashes in Sweden and examine injury causation mechanisms. Studies shows that the commonly used Hybrid III dummy is not fully reproducing the kinematical behavior observed in frontal sled test with belted PMHS (Post Mortem Human Subject). A human FE-model (Finite Element) might be able to reproduce the behavior evidenced with the PMHS in order to study upper body kinematics in certain types of frontal collision events.Method: A new data collection method was developed with the purpose to examine actual load paths active in the car front during a frontal crash. An important purpose was to examine if there was a relation between these load paths and injury producing mechanisms. This was done in an examination and analysis of 61 fatally injured occupants in 53 car frontal crashes in a sample area covering 40 % of the population of Sweden. Sample period was one year (1st October 2000 to 30th September 2001). An existing human FE-model was developed and validated with respect to upper body kinematics by using existing frontal belted PMHS tests. This was done by building a FE-model of the seat and seat belt used in the PMHS tests.Results: A generic car structure was developed which was used in the data collection methodology. By adopting this new method, Small Overlap (SO) crashes emerged as the most common crash configuration (48 %) among belted frontal fatalities. The injury producing mechanism in SO crashes is characterized by occupant upper body impacts in the side structure (door, a-pillar) of the car. This upper body kinematics is induced by both the crash pulse and the asymmetrical three point belt system. Current crash test procedures are not designed to fully estimate the performance of neither car structures nor restraints in SO crashes. In order to develop a better tool for reproducing this kinematical behavior a FE-model of a human body was refined and validated for belted conditions. This validation was performed with satisfying result.Conclusions: This study showed that by adopting new methods of data collecting new areas of traffic safety could be considered. In this study SO (48 %) crashes emerged as the most common crash configuration for belted frontal fatalities. Approximately ¼ of the fatalities occurred in a crash configuration comparable to current barrier crash test procedures. The body kinematics of PMHS in the SO crashes can be replicated and studied by using a FE-model of a human body in the collision load case model. With this tool possible collision counter measures could be evaluated for the SO crash configuration.
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| 8. |
- Lundgren, Peter, 1977-
(författare)
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Protection and treatment of hypothermia in prehospital trauma care : with emphasis on active warming
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: In prehospital trauma care active warming is recommended to aid in protection from further cooling. However, scientific evidence of the effectiveness of active warming in a clinical setting is scarce. Also, evaluating the effectiveness of active warming, especially in harsh ambient conditions, by objective measures, is difficult. Objective: To evaluate the effectiveness of field applicabe heat sources (I) and to evaluate active warming intervention in a prehospital clinical setting (II and III). To evaluate reliability and validity of the Cold Discomfort Scale (CDS), a subjective judgement scale for assessment of the thermal state of patients in a cold environment (IV). Methods: In a laboratory trial, non-shivering hypothermic subjects (n=5), were cooled in 8 ºC water followed by spontaneous warming, a charcoal heater, two flexible hot-water bags or two chemical heat pads, all applied to the chest and upper back (I). Oesophageal temperature, skin temperature, heat flux, oxygen consumption, respiratory rate and, heart rate were measured. In two clinical randomized trials, shivering patients during road and air ambulance transport (II) and during field treatment (III) were randomized to either passive warming alone (n=22 and n=9) or to passive warming with the addition of a chemical heat pad (n=26 and n=11). Body core temperature, respiratory rate, heart rate, blood pressure (II) and the patients’ subjective sensation of thermal comfort (II and III) were measured. In a laboratory trial, shivering subjects were exposed to – 20 ºC (n=22). The CDS was evaluated regarding reliability, defined as test-retest stability, and criterion validity, defined as the ability to detect changes in cold discomfort due to changes in cumulative cold stress (IV). Results: In non-shivering hypothermic subjects postcooling afterdrop was significantly less for the chemical heat pads, but not for the hot water bags and the charcoal heater, compared to spontaneous warming (I). Temperature drop during the entire warming phase was significantly less for all the heat sources respectively, compared to spontaneous warming (I). During road and air ambulance transport, ear canal temperature was significantly increased and cold discomfort significantly decreased, both in patients assigned to passive warming only, and in patients assigned to additional active warming (II). During field treatment, cold discomfort was significantly reduced in patients assigned to additional active warming, but remained the same in patients assigned to passive warming only (III). Weighted kappa coefficient, describing test-retest stability, was 0.84 (IV). CDS ratings were significantly increased during each 30 minutes interval (IV). Conclusion: In non-shivering hypothermic subjects, heat sources were effective to attenuate afterdrop, when providing high heat content over a large surface area and effective to continue to increase body core temperature when providing sustained high heat content. In shivering trauma patients, adequate passive warming were sufficient treatment to prevent afterdrop, to slowly increase body core temperature, and to reduce cold discomfort. If inadequate passive warming, additional active warming was required to reduce cold discomfort. The CDS, a subjective judgement scale for assessment of the thermal state of patients in a cold environment seemed to be reliable regarding test-retest stability and valid regarding ability to detect change in cumulative cold stress.
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| 9. |
- Styrke, Johan, 1980-
(författare)
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Traumatic brain injuries and whiplash injuries : epidemiology and long-term consequences
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- BackgroundThe incidence of traumatic brain injuries (TBI) is about 500 cases per 100,000 inhabitants per year, a majority of which are mild TBI (MTBI). The incidence of whiplash injuries is about 300/100,000/year. There are several similarities between MTBI and whiplash injuries with regard to the causes of injury (traffic crashes and falls), the demographic profile of the injured (mostly young persons), and the type of symptoms exhibited by some of the injured (for example head/neck pain, fatigue, irritability, impaired cognitive functioning, and depression). Main aimTo investigate the epidemiology and long-term consequences in terms of symptoms, disability, and life satisfaction in cases of TBI and whiplash injuries in a well-defined population.Material and methodsData on frequencies and characteristics of TBI and whiplash injuries were extracted from the injury database at the emergency department (ED) of Umeå University Hospital (UUH). The results were presented as descriptive epidemiology.The 18-65 year-old persons who sustained an MTBI or whiplash injury in 2001, were provided a questionnaire three and five years after injury respectively, in which questions were asked about:Symptoms; Rivermead Post Concussion Symptoms Questionnaire (RPQ) Disability; Rivermead Head Injury Follow Up Questionnaire (RHFUQ)Life satisfaction; LiSat-11A local reference population was used for comparison of the RPQ. A national cohort was used as reference for LiSat-11. Data on sick leave for the cases of whiplash injuries were analysed to calculate the cost to society for loss of productivity.ResultsIn 2001, the incidence of TBI was 354/100,000/year. The mean age was 23 and 55% were men. Ninety-seven percent of the injuries were classified as mild (Glasgow coma scale 13-15). The main causes were falls (55%) and traffic related injury events (30%). In 8% of the cases (17% of the elderly persons) an intracranial bleeding was detected by using CT.The 3-year follow-up of the MTBI patients showed that women had more symptoms and disability (~50%) than men (~30%). Both women and men had more symptoms and lower life satisfaction compared with the reference population.The incidence of traffic-related whiplash injuries in adults was 235/100,000/year and the annual incidences were relatively stable during 2000-2009. Combining the incidences with national insurance data showed that the proportion of insurance claims decreased during the period.When looking at whiplash trauma following all causes of injury in 2001, traffic crashes caused 61% of the injuries and falls caused 14%. Neck fractures occurred in 3% of the cases.Five years after whiplash injury, the injured persons had more symptoms and lower life satisfaction than the references. Sick leave ≥15 days was granted in 14% of the cases of whiplash injuries. The median number of sick days was 298 and the cost of loss of productivity during the follow-up was 5.6 million USD.The frequencies of symptoms were relatively alike when comparing subjects with whiplash injuries to subjects with MTBI.ConclusionTBI and whiplash injuries are common, especially among young people, and the injuries render long-term symptoms, disability, and impaired life satisfaction in up to 50% of the cases. Symptoms exhibited are alike between the two types of injuries. The cost to society for loss of productivity is high, and there is a need for enhanced preventive measures aiming at reducing traffic-related injuries, sports injuries, alcohol-related injuries, and falls. Physical, mental, and social factors are important and should be addressed when examining and treating patients with persisting symptoms following TBI and whiplash injuries.
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| 10. |
- Westman, Anton, 1972-
(författare)
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Dangers in sport parachuting
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Sport parachuting is a dangerous recreational activity for which available literature appears unsatisfactory to form a basis for injury prevention. Aim Overall: Explore some risk factors in sport parachuting. Study I: Identify fatal incident and injury mechanisms for skydiving (sport parachuting from aircraft). Study II: Identify fatal incident and injury mechanisms for BASE jumping (sport parachuting from fixed objects) for each of the four fixed object types B-A-S-E (building, antenna, span, earth). Study III: Identify non-fatal incident and injury mechanisms for skydiving. Study IV: Evaluate the validity of a compulsory reporting system among active skydivers. Study V: Explore some aspects of the Swedish skydiving culture and its relation to injury risks and injury reporting. Study VI: Describe the mechanism of incident and injury for a free fall shoulder dislocation.Methods Descriptive epidemiological studies of (I) fatal injury events in Swedish skydiving, (II) fatal injury events in BASE jumping worldwide, and (III) non-fatal injury events in Swedish skydiving. Self-report survey of (IV) Swedish skydivers to measure: Sensitivity, as the proportion of injury events fulfilling the reporting criterion that were actually reported; Specificity, as the proportion of false positives in relation to the defined gold standard. Content analysis of (V) Swedish skydiving participant narratives. First-person narrative and free fall video recordings (VI) of one case.Results Overall: Risk factors associated with “free fall” flight of the human body and recreational usage of parachutes were described. Study I: Fatal risk factors in skydiving included student instability in free fall, leading to unstable parachute activation with subsequent line entanglement or parachute activation failure. Unintentional water landings also contributed to fatalities. Every fourth skydiving fatality survived impact and died during transports or in hospitals. Study II: Fatal risk factors in BASE jumping included parachutist free fall instability, miscalculation of free fall acrobatics, deployment failure by the parachutist, pilot chute malfunction and parachute malfunction. In cliff jumping (BASE object type E), parachute opening towards the object jumped with subsequent collision was a frequent factor. Poor visibility, strong or turbulent winds, cold and water also contributed to BASE jumping fatalities. Study III: Non-fatal risk factors in skydiving included experience level and type of student-training system. The lower extremities, spine and shoulders were important regions of injury. The most serious injuries were seen in experienced skydivers. Study IV: The overall sensitivity of the skydiving injury reporting system was 0.37 (95% confidence interval (CI) 0.24-0.51). With non-minor injuries as the target for reporting, the sensitivity was 0.67 (95% CI 0.43-0.85). No significant effect on reporting was found for gender, age, license level, years in the sport, total number of jumps or club affiliation. The specificity was 0.91 (95% CI 0.83-0.95). Study V: It is suggested that Swedish skydiving culture is carried by the local club; not the national association. Skydiving culture at the local drop zone and formal and informal hierarchical structures among skydivers may be what really decides how rules are enforced, risk-taking behavior is seen, and if incidents and injuries are reported. Study VI: The free fall airstream forces were in this case strong enough to dislocate a shoulder joint, which has safety implications that should be considered by participants and medical doctors performing precourse examinations.Conclusion A number of risk factors in sport parachuting are described. Some technological, training and regulatory interventions are suggested to increase safety.
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