Air vests and body protectors compared in eventing falls study

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Paul Tapner and Bonza King of Rouges come to grief at Badminton in 2017. Miraculously, both walked away from the accident. © Mike Bain

Analysis of eventing falls has found that the use of an inflatable air jacket or vest was significantly associated with serious or fatal injuries by riders.

The findings were made during a retrospective analysis of FEI eventing data by Lyndsay Nylund as the basis of a thesis at the Faculty of Health Sciences, Discipline of Exercise and Sports Science, at the University of Sydney in Australia.

Nylund, a former international gymnast and coach who now runs clinics training riders to fall safely,  related the severity of the injury resulting from a fall to whether the rider was wearing an air jacket at the time.

Inflatable vests for horse riders have been available for several years. A gas canister, connected by a cord to the horse’s saddle, is discharged when the cord is pulled during a fall, inflating the jacket in a fraction of a second.

Air jackets aim to disperse the force of impact in a fall and reduce compression of the chest.

Between 2015 and 2017, 1819 riders fell wearing an air jacket and 1486 riders fell while not wearing an air jacket. Nylund categorised the injuries as either ‘no/slight injury’ (3203 riders) or ‘serious/fatal injury’ (102 riders).

Statistical analysis of the data showed that the use of an air jacket was significantly associated with serious/fatal injuries in falls.

The research has been published in the Journal of Science and Medicine in Sport.

“Riders wearing an air jacket were over-represented in the percentage of serious or fatal injuries in falls compared to riders who only wore a standard body protector,” Nylund said.

He added that riders wearing an air jacket had 1.7 times increased odds of sustaining a serious or fatal injury in a fall compared to riders not wearing an air jacket.

The findings raise several questions, including the possibility that riders wearing air jackets feel better protected and so take more risks. Are air jackets being worn by more advanced riders on more challenging courses?

Nylund suggests that further work is needed to understand the reasons for these findings. He recommends that additional data on injury outcomes, rider characteristics and the biomechanics of falls be examined in future analyses, and that air jacket and body protector characteristics be further investigated.

Equine Science Update

Do riders who wear an air jacket in equestrian eventing have reduced injury risk in falls? A retrospective data analysis. Nylund LE, Sinclair PJ, Hitchens PL, Cobley S. J Sci Med Sport. 2019 May 25. pii: S1440-2440(18)30588-7. doi:10.1016/j.jsams.2019.05.012

3 thoughts on “Air vests and body protectors compared in eventing falls study

  • June 30, 2019 at 7:30 pm
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    For those of you who go on and read the entire pubication, you may notice there are some major flaws in the design of this study that have resulted in spurious associations. From a statistical point of view if you don’t adjust for confounders you end up getting false results:

    e.g Confounder 1 – Eventing Disciplines
    The study designers (Nylund et al) acknowledge that they included falls in all eventing disciplines, not just the cross country stage. This is a fundamental flaw in the design of the study because most eventers know that Air Vests are pretty much only worn in the XC stage, because the falls in this stage are usually much more severe due to the speed and size of the jumps. Falls during the dressage and showjumping stage are in comparison much less severe and riders do not in general wear Air Vests during these stages. So if you are comparing air vest wearing to non air vest wearing, to the severity of the fall, then with their study design you are biasing the dataset and effectively comparing XC to dressage/SJ fall severities.

    Confounder 2 – Cross Country Levels (1-4*)
    The study used data from the FEI which also categorize the severity of falls by the level of XC event. Within XC, 1* the jumps are small and the speed required is slower. Thus in general less severe accidents happen at this stage and consequently, it has been observed that fewer riders wear air vests at this level. At 4* the converse is seen, jumps are bigger, accidents are more severe and more riders wear Air Vests/Jackets. So again there is a biased, its not necessarily a true comparison of airvest to non airvest with fall severity but 4* to 1* with fall severity.

    Unfortunately, poor science does still get published. When a study is so poorly designed it’s always worth looking at the motivation of the author. Nylands clinic’s are expensive and profit-based and he openly says he can’t teach how to fall mechanisms such as “tuck and roll” with an air vest on, so its a shame he has a personal gain should air vests be publicly discredited. My affiliation? nothing, just a scientist and mother of a daughter who rides. I certainly won’t be removing the air vest from my daughter based on this study.

    Reply
    • July 4, 2019 at 2:23 pm
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      Maria, in response to your comments:

      If you read the entire article you would have read in the discussion section, “The available data only enabled investigation of the association between air jacket usage and injury severity and not the reason(s) for the association. Therefore, the significant association does not necessarily mean that air jackets are the cause of increased serious/fatal injuries. Further investigation is required to understand the reason(s) for the association.”

      There are a number of potential variables (confounders, effect modifiers, and possible explanatory variables), that could explain the association between air jacket usage and serious injury risk in addition to the ones you have pointed out. A French study which, investigated the effectiveness of air jackets just for the cross country phase, had a similar pattern in their data to ours, 13.7% (7/51) serious injuries sustained by riders who fell wearing an air jacket, and 9% (1/11) for those who fell not wearing an air jacket. Their finding was not statistically significant though, because of the small sample size of about 60 cases of falls, vs over 3,000 in our study.

      In the final paragraph of the discussion section, you would have seen, “Further research is warranted to determine causative factors for the identified association between air jacket use and serious/fatal injury rate and, if necessary, to investigate possible means to attenuate risk. It would be beneficial to include additional data on the relationship between air jacket usage and the level of competition, event, horse and rider characteristics, the biomechanics of falls, injury mechanisms and the exact nature of injuries sustained in future analyses. Data should also be included on the brand and model of body protectors and air jackets worn, including measures of longitudinal bending stiffness, anatomy coverage, air jacket activation acoustic level, and impact absorption characteristics. The effect of lanyard pull forces on rider fall trajectory could also be assessed. Future analyses could then be conducted with more comprehensive datasets in a multivariable model that include effect modifiers.”
      There was no flaw in the design, the study was carefully checked by well-respected career research professionals and went through a blind peer review process, so it was simply a case of deciding whether or not the association that was evident from the available data should be reported or not. This often happens in research and sometimes raises more questions than providing answers, and can be a catalyst for further research to possibly answer the questions. The authors made no recommendation that riders should or should not wear an air jacket; this is entirely up to each rider to decide, based upon their own assessment of the risks.
      Your comment about the author, “he openly says he can’t teach how to fall mechanisms such as tuck and roll with an air vest on” is false. I have never made any such comments so I don’t know where you have dredged this up from or why you say that. Many riders who have attended my fall safety clinics have been air jacket users. Once again if you read the entire article, you would have noticed in the acknowledgement section, “The corresponding author is affiliated with Horse Rider Fall Safety Training, a business that conducts fall safety training for riders. He does not have any financial interest in air jackets or air jacket suppliers, and air jacket usage by riders has no influence on the business or the skills that are taught.”
      Finally, speculation and debate on the reasons for this unexpected finding is a good thing because further research is definitely needed, and this research has potential to suggest improvements in air jacket design and also identify other possible means to improve rider safety. But questioning the motivations/ethics of a scientist and a safety coach. . That’s inappropriate . . . play the ball, not the person.
      Lindsay Nylund (corresponding author)

      Reply
  • July 1, 2019 at 6:49 am
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    Every efforts to increase the safety are important but the fatality remains

    Reply

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