How High is Your Injury Risk in a Tough Mudder?

Have your friends been trying to convince you to do a Tough Mudder or a Spartan Race? You are not alone. We wrote about How to Train for a Tough Mudder or Obstacle course last year, but it has since grown even more.

Obstacle races are on the rise, with over a million participants every year. There’s no question that they can be loads of fun, but being the injury-averse runner you are, you might be wondering about the risks.

Just how dangerous is a mud run? What are your odds of spraining your ankle, breaking your arm, or winding up in the emergency room with some other awful injury that will keep you from making it to the start line of your next running race?

Obstacle races are a relatively new phenomenon, so there isn’t an overwhelming amount of data to review, but there are enough scientific reports and case studies to at least get an idea of the kinds of injuries that can occur and roughly how risky (relative to other events, like a running race) a mud run can be.

Just how likely are you to get injured?

A number of case reports have described some spectacularly scary injuries sustained by participants in mud runs and other obstacle races: Fainting, head injuries, electrical burns, dislocated shoulders, and broken bones. But of course, most of these things (barring electrical burns!) occur from time to time at road races too.

Hardcore running fans will remember 2006 Chicago Marathon champion Robert Cheruiyot slipping on the timing mats at the finish line at that race, falling backwards and hitting his head on the concrete. Cheruiyot wound up in the hospital for two days. Surely, this sort of thing must happen to the middle-of-the-pack runners every now and then, too.

The best way to gauge relative risk is to look at the records of the medical personnel who manage an event.

A 2014 report by several medical doctors at Lehigh Valley Hospital in Pennsylvania detailed the rate of serious injury among 22,000 participants in a Tough Mudder event.1

Thirty-eight participants sustained injuries serious enough to merit being transported to the hospital. To make risk comparisons easy, scientists often standardize rates. In this case, the numbers work out to 1.72 hospital transports for every 1,000 participants at this event.

A response to this paper, by Stephen Luke and Martin Dutch, medical doctors in Melbourne, Australia, contrasted this relatively high rate in the Pennsylvania event with their own experience providing medical care for a Tough Mudder event held in Australia, which also had about 22,000 participants.2

Their event was a quite far from any local hospitals, so they set up a “field hospital” to treat serious but not life-threatening injuries on-location. By doing so, they were able to stabilize broken bones (twelve cases), treat dislocated shoulders (twelve cases), and clean and apply stitches to deep cuts (twenty-six cases), which kept the local hospital from getting bogged down in case somebody really needed hospital transportation.

This resulted in only three patients being taken by ambulance to a hospital, though ten additional patients were sent to the hospital by private car, implying a rate of 0.59 hospital transportations per 1,000 participants.

An additional fourteen participants were referred to their family doctor; including them in the calculation bumps up the rate of medical referral to 1.23 per 1,000.

If we look at the total number of patients treated at the field hospital—126 people, which includes all of the above-mentioned case too—we get a rate of 5.73 “field hospitalizations” per 1,000 participants.

Now, this last rate is probably too high, since many of the injuries treated were not serious enough to even warrant referral to a family doctor. But the range of medical transport rates provided by the Pennsylvania study and the various ways of interpreting the data from the Australia study peg your risk of winding up in the hospital because of a Tough Mudder at somewhere between 1 and 6 in 1,000, roughly speaking.

Comparing to the injury risk of a marathon

You’re probably wondering how this risk compares to typical hospital-transportation rates at an event like a big-city marathon. Fortunately, a 1999 report by William Roberts, medical director of the Twin Cities Marathon, provides us with the data we need.3

Roberts’ paper describes the various injuries and illnesses that occurred over a twelve-year period at the Twin Cities Marathon. Some 81,000 runners started the race during this time period, and of these, thirty were transported to a hospital.

Thus, the hospitalization rate for the Twin Cities Marathon over this period was 0.37 per 1,000 participants. Roberts is careful to point out that Twin Cities is run in fairly cool temperatures—races run in the heat of summer probably carry a greater risk.

So, should you run that mud run all of your friends are doing?

There are two ways to look at it. On one hand, your absolute risk of injury is still quite low. At worst, six in one-thousand participants in an obstacle race wind up headed to the doctor’s office, the ER, or the hospital. Even this worst-case scenario only represents a 0.6% chance.

On the other hand, when comparing the risks of an obstacle race to running a marathon, the mud run is three to fifteen times more dangerous, depending on which data set you’d prefer to use.

Conclusion

There’s no denying these events can be a lot of fun, so your risk tolerance is going to be what dictates whether or not you should do an obstacle race while you’re training for a “real race.”

Are you okay with about a half of a percent-chance of a broken bone, dislocated shoulder, or other significant injury?

Does a three to fifteen-fold increase over a lower-risk event like a road race scare you off? If you’ve been training for years to qualify for the Boston Marathon, and you finally got in this year, maybe this spring is not the best time to do a mud run. But if you’re a bit of an adrenaline junky and there aren’t any immensely important races on the horizon, go right ahead!