Page 139 - JSOM Summer 2022

Among the more serious injuries reported during OCEs were proportion of soft tissue injuries. Unfortunately, temperatures
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dislocations and fractures; these were also reported in the or other weather data were not provided in the article. Data
four case studies of injuries during military obstacle course from Hawley et al. on events conducted from May to August
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events. 15–18 Lund et al. reported 15 shoulder dislocations in Canada showed a temperature range between ~52° to 80°F.
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(1.0% of 1,458 encounters), Luke and Dutch reported 12 Secondary analysis of the data at these two temperatures indi-
(2.7% of 441 encounters), and Greenburg et al. reported four cated an encounter incidence of 0.80% at ~50°F and 0.64%
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(10.5% of 38 emergency room visits). Coleby et al. reported at ~80°F (P =.43; RR = 1.22, 95% CI = 0.75–1.99). However,
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2 fractures (1.2% of 165 encounters), Luke and Dutch 12 these temperatures were not widely different.
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(2.7% of 441 encounters), and Greenburg et al. five (13.2%
of 38 emergency room visits). As shown in Table 3, Hawley Secondary analysis of data from Hawley et al. indicated that
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et al. reported 25 “possible fractures” and 3 “obvious frac- encounter incidence was similar among men and women with
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tures” (4.6% of 557 encounters). men = 1.0%, and women = 1.1% (P =.18; RR [women/men] =
1.13, 95% CI = 0.94–1.38).
Self-Reported Extremity Injuries
Examining medical encounters among individuals reporting to Rabb and Coleby reported on the effect of race length on
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medical care providers is important, but it does not capture medical encounters and two other studies 21,23 provide some
all injuries and illnesses. Participants often self-treat medical data that can also be used to look at this factor. As shown in
problems and these are not captured in studies involving only Table 4, race length was not associated with medical encoun-
those who are seen by medical care providers. ter incidence.
One study used an on-line survey distributed by social me- Infection Hazards
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dia to ask participants about upper and lower body extremity Obstacle course races are commonly held in wilderness and
injuries during OCEs. The questionnaire included items on rural areas. The mud and water on the courses can be con-
demographics (gender, age, height, weight, body mass index) taminated with microorganisms from the natural environment
and training characteristics. There were159 respondents with or from fecal material produced by cows, horses, and other
42 (27.4%) reporting at least one extremity injury. Of those animals. There have been at least two reports of diarrheal
injured, 60% reported a lower body injuries, 29% an upper disease outbreaks following OCEs. 27,28 Other infectious out-
body injury, and 12% both upper body and lower body in- breaks in outdoor events involving muddy conditions have
jury. None of the demographic factors was associated with the also been reported. These have included diarrheal outbreaks
extremity injuries. However, more time spent in training and after mountain bike races in extremely muddy conditions, 34–36
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more OCEs in the last year were associated with higher risk of skin infections after a mud football event, and skin infections
limb injury. A limitation to this study was that it only obtained after a college mud wrestling event. 38
upper and lower body limb injuries and not injuries to the
torso and spine. However, torso and spine injuries appear to In the OCEs and mountain bike races, epidemiological inves-
be less common in OCEs. 23,24 tigations have pointed to ingestion of microorganism contam-
inated mud or muddy water as the most likely cause of the
Risk Factors for Medical Encounters diarrheal infections. 27,28,34,35 Infection could occur from direct
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Beside time spent in training, few investigations have re- ingestion or from food or drink contaminated with mud and
ported risk factors for medical encounters during OCEs. How- consumed on the course or after the race. In the mud wres-
ever, secondary analysis of the data in some studies is possible tling and mud football events microorganisms likely entered
and this allows for an examination of some potential risk fac- the body through lacerations, abrasions, or hair follicles. 37,38
tors including season (winter vs summer), sex, and race length.
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An illustrative example of a study examining a diarrheal out-
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Agar et al. reported that medical encounters were more break is that of an OCE held Beatty, Nevada, in which both
common in the winter than in the summer. Secondary anal- active duty service members and civilians participated. The
ysis of their data indicated a winter encounter incidence of outbreak investigation began when three service members re-
1.6%, and a summer encounter incidence of 0.9 (P <.01, rel- ported to the emergency department at Nellis Air Force Base
ative risk [RR] = 1.67, 95% CI = 1.30–2.15). The types of (Nevada) experiencing fever, vomiting, and hemorrhagic di-
medical encounters differed in the two seasons. In the winter arrhea. They had participated in a “long-distance adventure
there was a higher proportion of hypothermia (defined in the obstacle race” (event not specified). Nellis Air Force Base
study as an oral or axilla temperature of <90°F) and lower Public Health in coordination with local and state health
TABLE 4 Medical Encounters in Relation to Obstacle Course Race Distances
Proportion
Obstacle Course Iterations Distance with Medical
Study Race (n) (km) Participants (n) Problems (%) RR (95% CI) p-value
Rabb & Spartan 19 5 48,271 2.42 1.00 Reference
Coleby 10 10 18,337 2.36 0.97 (0.87–1.08) 0.62
2018 24
4 24+ 6,146 2.68 1.10 (0.94–1.30) 0.22
Hawley et al. Mud Hero 7 6 44,686 1.24 1.00 Reference
2017 23 1 10 599 0.83 0.68 (0.28–1.62) 0.38
Lund et al. Warrior Dash 2 5-6 10,200 3.44 1.00 Reference
2015 21 Tough Mudder 2 16-19 35,125 3.16 0.92 (0.81–1.08) 0.14
Abbreviations: 95% CI = 95% confidence interval, RR = relative risk

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