The Warrior Dash. The Spartan Race. The Hell Run.

With their rugged titles and descriptions evoking the no-cry babies brand of military boot camp training, the popularity of extreme sporting events is on the rise. 

But so too are event-related injuries, which are often equally extreme, according to a case series prepared by practitioners at Allentown's Lehigh Valley Hospital and published in the Annals of Emergency Medicine.

An estimated 1.5 million people will this year participate in obstacle races like the Tough Mudder. The 10- to 12-mile endurance course features a revolving menu of hurdles with names like the "Arctic Enema" and "Dong Dangler." One challenge, aptly termed "Electroshock Therapy," requires participants to run through mud and water while dodging wires that purportedly deliver 10,000 volts of electricity.

Still, those obstacles can't be as dangerous as they sound, right? Not so fast. 

During Pennsylvania's last Tough Mudder, held the weekend of June 1 at Jaindl Farms in Schnecksville, Lehigh Valley Hospital alone saw 38 emergency department visits, according to the medical report titled "Unique Obstacle Race Injuries at an Extreme Sports Event: A Case Series." In all, 100 event participants received emergency treatment at the event, though many of them declined further medical attention.

"Anytime you get a volume of a large number of patients, it's always unanticipated," said Lehigh Valley Hospital's director of emergency medicine research Dr. Marna Rayl Greenberg, one of the study authors. "But it was more the type of injuries we saw that were unique to the sporting event that caught our attention."

The injuries were a far cry from the sprains, ligament tears and heat exhaustion doctors commonly see during marathon races or triathalons. A sizable proportion of the wounded suffered open fractures requiring surgery and electrical injuries that ranged from seizure-induced paralysis and cardiac inflammation to burns and lacerations.

"The unique part is this type of injury pattern from an obstacle course — meaning the electrical injuries — had never been documented in the literature before, and that's what made us decide to write the article," Greenberg said.   

According to the study, one man, 18, received a staggering 13 shocks during the Tough Mudder's last obstacle. The shocks left numerous electrical burns on his back and arm and caused his heart muscle to become inflamed. A second man, 28, who sustained multiple electrical shocks to the head while running through water, experienced fainting and an altered mental state - a result of an acute electrical injury that inflamed the tissue surrounding his heart. Both patients were admitted to the hospital.

"The electrical injures that happened that day were either from a current that was discharged directly to participants' skin, their heart muscle or their brain, combined with the fact the participants were hot and wet and tired, or they were the types of injuries where they were so startled by the current or jolt, they would fall and hurt other parts of their body," Greenberg said.

For example, a 41-year-old man who fell unconscious after he was struck in the head by two electrical cords and landed face-first in a hard mound of dirt was discharged against medical advice after being diagnosed with a broken nose, electrical injuries and face lacerations.

Participants' ages and relative fitness levels didn't seem to make a difference when it came to injuries. "One of the generalizations might be that the people who got hurt were the least healthy and that was, in our experience, not true," Greenberg said. "For instance, one of the very healthy 31-year-old participants who ran two to three miles a day is one of the injured patients who had a stroke."

That man completed 20 of the Tough Mudder's 22 obstacles before suddenly becoming confused, experiencing difficulty speaking and losing movement of his entire right side. He was admitted to the intensive care unit with Todd's paralysis after tests revealed he suffered an injury-related stroke. Though he was four days later discharged to a rehabilitation center, he reported continuing disabilities in his lower right leg - six months after he'd completed the race.

Unlike marathons, in which athletes can minimize injuries by building strength and endurance ahead of the race, events like the Tough Mudder pose training challenges. "In our medical opinion, there isn't a way to prepare for the injuries that can be sustained as a result of electrical shock," Greenberg said. "You can't build up a tolerance to that."

Plus, the incidence of injuries like those detailed in the paper may only continue to rise. If the injury rates detailed in the study are extrapolated to the 1.5 million people expected to participate in extreme obstacle course events this year, an estimated 2,590 of them will suffer injuries requiring hospitalization, while 5,800 will need treatment from on-scene paramedics. "That, in our opinion, is worth spending the time looking at how we can minimize risks for those people," Greenberg said. 

The American College of Emergency Physicians has not yet made an official policy statement regarding the safety of extreme obstacle course events. But Greenberg and other study authors recommend adrenaline junkies avoid electrical obstacles until further medical evaluations and safety assessments are undertaken. They also suggest event organizers ensure there is adequate medical personnel and equipment on site.

"We mean the study to be the start of a conversation to increase the awareness of the possibility those injuries may not have just resulted from the combination of shock, wetness and heat that day," Greenberg said. "These were unusually severe injuries, and we would like not to see that happen to participants."