These days, you can’t go to an action movie without seeing crazy car crashes and gigantic explosions. But who is behind these dangerous stunts you see on the big screen? Complex spoke to Hollywood’s leading stuntmen, who shared intriguing insight into this exciting yet terrifying world.

Kevin Scott, Stunt Coordinator

Being a stuntman is one of the greatest jobs in the world, says Kevin Scott, stunt coordinator for the movie, Lone Survivor (out on DVD and Blu-ray now). “We get paid to play! We travel all over the world and work with incredibly talented people in all trades of entertainment. If you're fortunate enough to stay busy, the money you can make isn't bad either!”

But what does it take to be a stuntman? Like any career, you have to have tools; for a stuntman, it’s his or her body.

“We are very much like a professional athlete,” Scott explains. “Most of us have a particular skill set that ‘got our feet in the door.’ Having experience in contact sports, gymnastics, boxing, martial arts, racing etc. is a good start. Then you begin what should be a never ending training regiment, working on the relevant skill sets to perform physical stunts.”

But more than being a jack-of-all-trades, the biggest challenge for stuntmen is to constantly up your own game. “You have to maintain your A-game. Competition is fierce in the stunt community. It draws some of the best performers from all walks of life," says Scott.

The film stunts in Lone Survivor required an approach that wasn't your standard tossing and tumbling. “It's a real story about men who went to war, and some didn't come back alive,” says Scott. “It was extremely important to the director, Peter Berg, and I, to create realistic visceral action sequences. We couldn't produce any ‘stunty’ looking performances. Every action shot represented a physical act the Navy SEALs experienced. As such, we wanted to make damn sure we got it right.”

As a result, the physical challenges on the film were immense—everything from treacherous terrain to hiking with over 60 pounds of gear.

Scott continues, “We filmed part of the movie at Ski Sante Fe in Sante Fe, New Mexico. The locations started at 10,500 feet elevation and continued to the top of the mountain at 12,400 feet. Most of our equipment had to be carried up the mountain. In addition, the fall sequences were difficult because we did not use any stunt pads for landings. The four stunt doubles landed on leaves and moss. This approach gave us an added sense of realism. We were able to set cameras dangerously close to the point of impact. We wanted the audience to see and feel what the SEALs went through on the mountain.”

What's more, Scott emphasizes that stunt players must be in top physical condition at all times. “On Lone Survivor, our extremely talented stunt players were no exception. There's a direct correlation with stunt performances and contact sports. While you can circuit train, perform cardio workouts and work on the relative physical needs of your skill sets, there are times when you just have to go out and hit it hard. The altitude presented challenges, but all the guys pushed through with extreme effort. While we do take calculated risks in our business, as a stunt coordinator, I must feel confident that our team is as strong as possible to meet the needs of the sequence.”

Sometimes a stunt player's on-camera opportunities are limited based on their size or a particular look. “Having acting skills expand ones ability on-camera and can open up opportunities playing ‘stunt parts,’” Scott says. “One skill that all stunt players need is an excellent sense of timing. Whether you're walking, running, jumping, diving or driving, you need to be at the right place or the right time. That skill is an absolute necessity to work on-camera and minimizing the risk of getting hurt.”

Sean Graham, Stunt Double for Mark Wahlberg

Sean Graham, the stunt double for Mark Wahlberg who starred in Lone Survivor, believes that being a working stuntman requires much more than just talent. “It takes a great deal of courage, instincts, timing, strength and dedication to make it in such a competitive business. Honesty and humility are a must in my eyes as well. Talent is a common thing. It is how and what you do with it that makes you unique.”

Being Wahlberg’s stunt double for the better part of 15 years has its challenges. Graham notes , “It requires some pretty major body transformations. [Mark] varies his size drastically from one movie to the next. On Pain and Gain, he pumped up to 212 pounds and then back down to 130-ish, for his upcoming film, The Gambler. He is extremely dedicated and talented. I do my best to transform with him.”

Graham’s next film with Wahlberg: Ted 2, which will soon begin filming in Boston.

Naturally, there are enormous risks that can potentially happen on a movie and television set, which Graham is well-aware of. “The obvious ones are of course injuries and even death, which unfortunately are a reality with this career choice. Injuries are common and often need to be ignored, in order to survive in the business. If you break or tear something, we as stunt performers often keep it a secret and finish the movie. I know it sounds ridiculous, but if you get replaced when doubling an actor it could be for good! I've worked through many broken bones, torn ligaments and concussions. Our mind has an amazing ability to overcome pain if you let it. You need to be willing to hurt for what you love with no fear!”

Vic Armstrong, Stunt Veteran

While safety is always an absolute priority, having the stunt look natural and believable for Hollywood audiences is just as important. “The challenges are working out how to safely do something dangerous and still make it appear dangerous,” says veteran stuntman Vic Armstrong, who was the second unit director and stunt coordinator on Jack Ryan: Shadow Recruit, which is in stores on Blu-ray and DVD now. “But the personal satisfaction of achieving that and thrilling audiences with your work—and the monetary rewards—are pretty good too.”

To that end, Armstrong says a big challenge in Jack Ryan was having Chris Pine ride a huge motorcycle at high speeds through New York and Liverpool as safely as possible without a helmet.

“We actually resurfaced a tunnel road with new nonslip tarmac in Liverpool, because it was old and slick and covered in grease and oil. It was impossible to ride on safely. Chris worked hard in training and it all went well. The fights had to be stylized so that they looked real. The director and co-star, Kenneth Branagh, wanted to feel that this was a guy that had no experience at fighting, just struggling and using his instinct to survive," says Armstrong. "We had a great stunt team and rehearsed every fight and motorcycle stunt well in advance. Since when we started shooting, we were flying from country to country, like London to New York, back to London to Moscow, then back to London then up to Liverpool which doubled for Moscow at night."

Armstrong has been doing stunts in films since the 1960's, and was Harrison Ford’s stunt double for the first three Indiana Jones films. Of that time period, Armstrong says, “They were all great fun with wonderful locations and everybody on the whole crew committed 100 percent to make three of the best action films there have ever been. It was all very hard work, but there were lots of laughs which is something that is missing these days.”

Susan Hornik is a contributing writer. She tweets here.

RELATED: The 50 Best Action Movies of All Time

RELATED: The 25 Best One-Liners in Action Movies