It's hard to tell who will have the higher adrenaline rush during the championship cycling races this weekend: The cyclists hurtling at breakneck speeds down mountains and highways - or the doctors leaning out of cars alongside them, trying to bandage injured-but-stubborn riders still on their bikes.
The mobile medical unit -- as the caravan of five vehicles staffed with doctors, nurses and paramedics is called -- is just one feature of the large and complex medical presence that will care for both athletes and spectators this weekend.
More than 150 medical personnel from Erlanger Health System, the medical sponsor for the championship races, have volunteered to help during the weekend.
"[The event] is going to be attracting thousands of people here," said Danielle Mitchell, a sports medicine physician who is medical director for the event. "So we have this need for community-based medical support, but you also have some very specialized care that happens in regards to professional athletes, and how it pertains to cycling."
Coordinators with Erlanger have been planning for the event since they formed the contract with USA Cycling in September, said Donna Bourdon, Erlanger's executive liaison of the project.
One group visited hospital staffers in Greenville, S.C., which hosted the championships for the last seven years.
"It's been a well-coordinated effort over a number of months to be prepared," Bourdon said.
LifeForce at Erlanger already oversees an event medicine program in the Chattanooga area, providing services at about 200 events per year, program administrator Robbie Tester said.
But this weekend's races present new challenges with the scope of the routes, the speed of the cyclists and the size of the crowds.
There are different medical strategies for the two racing events. For the shorter timed trials on Saturday, there will be medical tents set up along the course with constant radio contact buzzing among providers.
But for the road races on Monday, the caravan will have to orbit the peloton of cyclists, sending a motorcycle -- or "medicycle," as Mitchell calls it -- up with those breaking away from the pack.
The tight corners and shifting speeds demand intricate choreography, and everyone needs be ready to improvise.
"You buckle into your car, and hope to God you've got a good driver," Mitchell says of the more tricky parts of the route. She has worked with USA Cycling since 2008, treating cyclists on several major tours.
USA Cycling provides all of those mobile medical drivers. Some are former race car drivers and state troopers.
If someone is injured, the mobile medics have to coordinate a response in less than two minutes because the race is still going.
"We have this ability to triage things with incredible rapidity because these races happen so quickly," said Mitchell, who is also a cyclist and member of USA Cycling.
If there is any major trauma at the event, there are two ambulances and LifeForce on standby. There also will be a base medical unit tent set up at the start-finish line to triage non-serious injuries.
Among the pro cyclists, the most frequent injuries are either musculoskeletal or related to heat and dehydration.
For spectators, the most common medical needs are heat-related, Tester said. There will be a separate tent and roving ATVs and bikes manned by medical staff to treat bystanders.
"We're prepared for anything, so we'll have complete advanced life support in our tents and carts," he said.
Recent tragedies at sporting events have underscored the need for a strong medical presence on site.
After the Boston Marathon bombings last month, the medical staff at the race was suddenly thrust onto the front lines of a major disaster with mass casualties. Many of those marathon medics later were heralded for saving lives and limbs.
And a local concern for safety was amplified after a cyclist was killed when he and a car collided in the 3 State 3 Mountain ride at the beginning of May.
Those events have spurred the medical committee approach their job with more gravity, Tester said. But it hasn't changed much about their preparations. They already have long lists of worst-case scenarios.
"We have a heightened sense of awareness," Tester said. "But we have trained for that kind of thing all along."
Contact staff writer Kate Harrison at email@example.com or 423-757-6673.