Sports Medicine Research: In the Lab & In the Field: Injury and Illness Rates in Multiday Ultramarathon Runners (Sports Med Res)


Tuesday, May 1, 2012

Injury and Illness Rates in Multiday Ultramarathon Runners

Study of Injury and Illness Rates in Multiday Ultramarathon Runners

Kraback BJ, Waite B. & Schiff MA. Medicine and Science in Sports and Exercise. 2011; 43: 2314-2320.

Ultramarathon races occur over the course of a couple of days, carrying gear/supplies, are up to 150 miles, and may include running extreme terrains.  Few studies have evaluated injuries among multiday ultramarathon runners.  Therefore, the purpose of this study was to evaluate injury/illness rates in a group of off-road ultramarthon runners during several similar races.  This particular series of 4 races were over 7 days across extreme terrain (e.g., dessert, wilderness), and participants were primarily experienced ultraendurance runners.  Medical checkpoints were staffed by physicians along the course and any injury/illness was documented if a runner encountered the medical staff.  Encounters were classified as minor or major in the following 3 categories: medical illness (e.g., hyperthermia, collapse, hyponatremia, cardiac), musculoskeletal injury, or skin disorder.  Four hundred and seven runners completed the races, and 396 (97%) participated in the study and were predominately male (79%).  Over the course of 4 races, 85% of runners were evaluated by medical staff and 15% required no medical care.  Almost 95% of all encounters were minor in nature.  Of these minor injuries 74% were skin related, 18% musculoskeletal, and 8% other medical illnesses.  Only 5% of the injuries were considered major, and this was mostly medical illnesses (e.g., hyponatremia, asthma, hematuria; 58% of all major injuries).  An increase in age was associated with a lower injury/illness rate and females had higher rates of illnesses than males. 

Despite difficult terrain, significant distances, and extreme weather conditions, injuries/illnesses that occur during these races are largely minor and frequently involve skin-related disorders of the foot.  This does not seem surprising.  Musculoskeletal injury rates (0.71 per runner) within this study were relatively lower than pervious findings on ultramarathoners.  What is also interesting is that injury rates in the population were significantly lower than rates previously found among marathoners.  Marathoners often include experienced as well as some less experienced runners.  In contrast, ultramarthoners consist primarily of experienced runners who have trained for these extreme conditions.  It would appear that conditioning, acclimatization, and physical strength may have influence on injury at this level.  Females have a higher incidence of illnesses, which may be attributed to the larger relative size of the 7 days worth of supplies that they must carry throughout the race.  What was also interesting is that this study stated that all participants were offered the same amount of water for any given day.  It would be interesting to see how much water was consumed by participants.  Females are susceptible to hyponatremia, therefore water consumption may influence the incidence of medical illnesses.  Runner education or monitoring of sweat rates may be critical to the understanding of these medical illnesses.  Also, most medical encounters happened early in the race.  This may have to do with acclimatization issues as well as travel (e.g., jet lag) issues.  Clinically, we may not encounter many athletes that are at this level, but it is very interesting and may have carryover to marathons and other running populations.  It appears that experienced runners have few injury or illness issues, and that we may need to target the less experienced runners.  A research study investigating marathon runners may help to see if experience level is protective within this population, as it appears to be in the ultramarathoners.  Does anyone have any experience with events like this, either as runners themselves or athletes that they have encountered?  

Written by: Nicole Cattano
Reviewed by: Jeffrey Driban

Related Posts:

Krabak BJ, Waite B, & Schiff MA (2011). Study of injury and illness rates in multiday ultramarathon runners. Medicine and Science in Sports and Exercise, 43 (12), 2314-20 PMID: 21552155


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