Text-only version
German Cardiologist Publishes Results of Roller Coaster Study
November, 2005
- After one minute on the ride, the average maximum heart rate of the participants increased from 91 beats per minute to 153 bpm. Women had higher maximum heart rates than men (average of 165 bpm vs. 148.5 bpm).
- 44% of the study participants had marked sinus arrhythmia that persisted for up to five minutes after the ride. One participant had a self-terminating episode of atrial fibrillation during the ride.
- Before the study, researchers thought the increased G-forces occurring when riders suddenly plummeted towards the ground would increase stress on the body and increase heart rate. "But the increased G-force didn't have too much of an effect on the heart rate," Kuschyk said. "The heart rate appeared to rise more from psychological stress and fear at the beginning as riders were climbing or reaching the top."
- Researchers concluded that riding roller coasters poses no cardiac risk to young healthy people; however, individuals with high blood pressure, a previous heart attack, an implanted pacemaker or defibrillator, or other heart disease were warned against riding roller coasters.
"Roller coaster related fatalities, United States, 1994-2004"
Source: Injury Prevention, October 2005
Summary:
Authors' Conclusions:
- Establishing an effective surveillance system for amusement ride injuries.
- Engineering rides to better protect both patrons and employees.
- Improving training and supervision of employees regarding safety precautions.
- Posting cautionary notices near roller coasters for people with specified medical conditions.
- Further research is needed on roller coaster related deaths resulting from intracranial hemorrhages and cardiac problems.
"Prevention of roller coaster fatalities is dependent on establishing an effective surveillance system for amusement ride injuries, engineering rides to better protect both patrons and employees, improving training and supervision of employees regarding safety precautions, and posting cautionary notices near roller coasters for people with specified medical conditions. Further research is needed on roller coaster related deaths resulting from intracranial hemorrhages and cardiac problems."
"Acute Soft Tissue Neck Injury from Unexpected Acceleration"
Source: Aviation Space Environmental Medicine, 2003:74:1085-90
Summary:
Authors' Conclusions:
- The mechanisms causing soft tissue injury of the neck under increased acceleration are complex and do not easily lend themselves to modeling or analysis. Further difficulty is encountered when considering the dynamics of the situation, which is compounded by the influence of head position, and combinations of G x , G y , and G z acceleration vectors.
- When unexpected acceleration is considered, the use of neck muscle strength may be less appropriate as the protection afforded by cervical muscles is not present from the outset, but is brought to bear during the acceleration exposure. Additionally, the delay in muscle contraction may increase risk of muscle overload injury due to head and neck inertia. Therefore it seems likely that an injury may occur at lower acceleration levels than those considered for expected accelerations.
- Mathematical models imply that improved cervical muscle strength may reduce incidence of soft tissue neck injury. The increased risk of injury in individuals with weaker necks, due to size or gender difference, is also highlighted.
- It is apparent that operationally significant soft tissue neck injury may be sustained at relatively low levels of unexpected acceleration, and probably at acceleration levels below accepted 'tolerance limits' given in the reference text ... Simulators, human centrifuges, and roller coasters all have the potential to cause soft tissue neck injury if they expose occupants to unexpected acceleration above the threshold levels described.
"Variability in the Control of Head Movements in Seated Humans: A Link With Whiplash Injuries?"
Source: Journal of Physiology, 2001, 532.3, pp.851-868
Summary:
Authors' Conclusions:
- The strategies used to stabilize the head-neck ensemble were surprisingly diverse amongst subjects. The head and body movements triggered by the high-jerk, linear acceleration were distributed in between two stereotyped extremes corresponding to two canonical types of subjects. The 'stiff' subjects showed little rotation or translation of the head relative to the trunk for the whole duration of the impulse. In contrast, the 'floppy' subjects showed a large roll or pitch of the head relative to the trunk in the direction opposite to the sled movement. This response appeared as an exaggerated 'inertial' response to the impulse.
- Despite the strong inter-individual variability, the responses were highly repeatable for both the stiff and floppy people with most subjects showing very similar traces on successive trials. The stiffness of the subjects was not significantly related to their age, height, or weight.
- The response of the floppy subjects appeared to be maladaptive and likely to increase risk of whiplash injury during motor vehicle accidents. Evolution of postural control may not have taken into account the implications of passive, high-acceleration perturbations affecting seated subjects.
- The visualization of an imaginary reference in space during sideways impulses significantly reduced the head roll exhibited by floppy subjects.
- The results suggest that stimulus jerk is probably a crucial factor in the occurrence of whiplash. However, during boxing matches, fist impulses can generate, in a few tenths of milliseconds, accelerations of the target head as high as 50g, which do not cause significant damage to the cervical column at least on a short term basis. Therefore, jerk cannot be the only factor involved.
- The authors propose that it is the ambiguous patterns of proprioceptive inputs in triggered by the unexpected event which caused the floppy subjects to involuntarily react with "inappropriate muscular synergies", adding the thrust of their own neck muscle contractions to the head inertia in a potentially harmful combination.
- The fact that the awareness of what is going to happen reduces the occurrence of neck injuries in car crashes supports the idea that the central nervous system is able to switch strategies depending on the behavioral context. This scheme might explain why whiplash injuries can be produced by low-amplitude accelerations, and why the neck injuries observed among different passengers of the same car can be quite variable.
"Amusement Park Injuries and Death"
Source: Annals of Emergency Medicine, January 2002
Summary:
Authors' Conclusions:
- Case reports have demonstrated subdural hematomas, internal carotid and vertebral artery dissections, and subarachnoid hemorrhage in association with roller coaster-generated G forces, but no research has determined the human G-force threshold for these injuries.
- The absolute strength (total Gs), the duration of G force, and the rate of intensification of G force are all important variables. It is certainly possible that lateral G forces, rotational acceleration, abrupt directional changes, and predisposing anatomic factors play an important role in these types of injuries as well.
- Although the current risk of injury, hospitalization, and death on amusement rides is extremely low, health care providers should be aware of a worrisome trend in the number and rate of amusement park injuries.
- Although data exist as to the threshold of G force needed to produce loss of consciousness in a controlled centrifuge, there is little or no data on the neurologic effects of intermediate duration G forces combined with rapid directional changes.
"Roller Coasters, G Forces, and Brain Trauma: On the Wrong Track?"
Source: Journal of Neurotrauma
Summary:
Authors' Conclusions:
- Estimated head rotational accelerations experienced by roller coaster riders are nowhere near the established injury thresholds for severe forms of brain injury.
- The press is confusing an increase in reports of brain injuries following roller coaster rides with an actual increased incidence.
- Roller coasters produce smaller head accelerations than amateur boxing, and none of the amateur boxers studied by the authors suffered head injuries.
- Automobile drivers and passengers should wear seatbelts.
Saferparks' Remarks:
- The authors based their findings on acceleration measurement data provided by the amusement ride industry for three roller coasters, and extrapolated those findings to encompass all amusement rides. The authors' methodology did not include an examination of the operational safety records of the roller coasters in their study.
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The second sentence of the article is factually incorrect. The authors state that "Congress has recently proposed legislation to regulate the level of G forces of roller coasters". The legislation introduced in the House of Representatives simply revokes a 1981 law exempting permanent amusement rides from compliance with the Consumer Product Safety Act. The CPSC does not impose limits on g-force for any of the products they regulate, including portable amusement rides.
The short text of the federal legislation is accessible online, had the authors bothered to verify the information provided to them by the amusement ride industry. Such sloppy fact-checking so early in the article casts doubt over the trustworthiness of the authors' research and findings, particularly since the conclusions are based on technical data which was also provided by the amusement ride industry.
"Investigation of Amusement Park and Roller Coaster Injury Likelihood and Severity"
Source: Exponent Failure Analysis Associates, August 2002
Summary:
Authors' Conclusions:
- Over the last 40 years, there has been no increase in accelerations produced in roller coasters.
- Computer analysis indicates that none of Six Flags' rides produce accelerations that could cause a rider to lose consciousness.
- Accelerometer measurements prove that riding roller coasters is safer than everyday activities such as sneezing, using a pogo stick, spinning in a tire, falling down, or having a pillow fight. People in amusement parks are at lower risk of spontaneous blood vessel rupture than they would be outside of the amusement park. Exponent did not offer a theory to explain this phenomenon.
- Exponent identified four major flaws in the sampling methodology used by the CPSC NEISS system, and concluded that the flaws reduce "the usefulness of NEISS data in estimating amusement park injuries and assessing trends". Nevertheless, Exponent went on to base five of their conclusions on this flawed data.
- An analysis of injury data from Six Flags' first aid stations shows that only 6% of patrons who reported injuries to the first aid station required transport to a medical facility. Only 5.8% of those patrons required in-patient hospitalization. Based on records provided by Six Flags, Exponent calculated the rate of emergency transport as seven injuries per million patrons.
Saferparks' Remarks:
- The Exponent report offers an interesting overview of some private and public sources of data on ride-related injury. Saferparks thanks Exponent and Six Flags for making this information publicly available.
- Exponent did not include in its survey injury information reported to state regulatory agencies across the country.
- The bulk of data reviewed by Exponent, including patron injury records, is owned by Six Flags and cannot be viewed or reviewed by the public.
"Fixed Theme Park Rides and Neurological Injuries"
Source: Neuro-KnowledgeT, Outcome Sciences, Inc.®, and the American Association of Neurological Surgeons, August 2002
Summary:
Authors' Conclusions:
- After reviewing multiple data sources, the panel determined that the available data sources are inadequate to provide the necessary data for determining the incidence and risk.
- The panel reviewed 20 brain injury cases published in medical literature and found 9 to be plausible (i.e., the panel could not rule out a causal relationship between the amusement ride and the injury.
- Although useful for establishing case type and raising issues that might be addressed by controlled studies, case reports cannot be used to determine the incidence rate nor magnitude of an association.
- There are no data in the extensive aeronautical and biomedical literature that describes the types of neurological injuries the panel was asked to study.
- The panel surveyed 282 practicing neurosurgeons. 33 of those physicians reported treating patients over the last 5 years who might have been injured on a normally functioning amusement ride with appropriate rider behavior.
- 44% of the fixed theme park neurological injury cases studied by the panel reported a suspected predisposing condition, although most of these conditions differed from each other. 68% of the injuries studied had complete resolution without disability.
- The panel concluded that the problem to society is negligible for any person without a known risk factor. There were no clearly predisposing conditions identified in the review of the literature.
- Additional effort should be made to develop and evaluate data sources to help identify other types of cases that might exist. Even with a very low incidence of injuries that may be attributable to fixed theme park rides, there would be value in further delineating the types of cases that exist beyond those reported in the current literature, with particular interest in identifying any injuries that might be avoidable.
- The feasibility of a prospective data collection approach for ongoing surveillance should be evaluated.
Saferparks' Remarks:
- The AANS report offers an informative review and interpretation of the existing data sources and biomechanical issues related to neurological injury on amusement rides. Saferparks thanks the AANS panel and Six Flags for making this information publicly available.
- The AANS panel did not include in its survey injury information reported to state regulatory agencies across the country.
"Blue Ribbon Panel Review of the Correlation Between Brain Injury and Roller Coaster Rides"
Source: Brain Injury Association of America, February 2003
Summary:
Authors' Conclusions:
- No systematically acquired comprehensive database, longitudinal history or natural history data was available.
- Location and type of accelerometers were found to be less than ideal and not as directly relevant to the linear and rotational accelerations of the head as would be desired.
- The report concluded that roller coasters pose a health risk to some people some of the time, but that "the risk of brain injury from a roller coaster is not in the rides, but in the riders." The report did not explain what the health risks are, or which riders are at higher risk on which rides, but "riders are encouraged to use common sense".
- The BIA report concluded with a recommendation that the theme park industry be allowed to keep its special interest exemption from all federal safety oversight because some amusement rides are designed with "multiple fail-safe features".
- The BIA's report also recommended that a nationwide oversight agency be created to ensure that the amusement ride industry consistently adheres to its own safety standards. The inherent contradiction between recommendations one and five was not explained.
Saferparks' Remarks:
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The BIA report is an excellent source of background information on the amusement ride industry, including park attendance figures, the text of a proposed engineering standard, and a timeline of the 600-year history of roller coasters. The BIA report did not, however, contain any information about the 57 reported cases of brain injury they were asked to study. The findings in the Executive Summary are not discussed in the main document.
Congressman Markey, who requested the BIA study, issued a press release stating that he was "puzzled by the decision of the panel to withhold the basis of their conclusions. By neglecting to publish the panel's work product, the panel undermines the validity of its own findings and throws a cloud over integrity of its work that is hard to dispel.
"Non-impact Inertial Injuries to the Brain and/or Its Accessories"
Source: Congressman Markey
Summary:
