When Lauren Kornacki discovered her father crushed beneath his BMW 525i,  which had slipped off the carjack as he was working on it, the 22-year-old wedged herself under the mid-sized vehicle -- and pulled it off her father.

We hear tales from time to time of people exhibiting superhuman strength in life-and-death emergencies. After experiencing amazement over such a feat, we all wonder: How can a regular person lift something that weighs more than a ton?

Actually, most people "can lift six to seven times their body weight," says Michael Regnier, professor and vice chair of bioengineering at the University of Washington. But most people don’t push themselves so hard, though athletes often push themselves more than most. Fear, fatigue and pain prevent people from attempting feats of amazing strength in daily life, says Dr. Javier Provencio, director of the neurological ICU at Cleveland Clinic.

Regnier, a former world-class weightlifter, has experienced bouts of incredible strength both as an athlete and as someone who helped after an accident. About 20 years ago, Regnier was driving on a Los Angeles freeway when he spotted a wrecked car on the side of the road. The driver sat slumped over his steering wheel so Regnier pulled over to help. It was instinct; he couldn’t fathom leaving the man without doing something. The driver’s door had caved in and Regnier couldn’t get him out any other way—he ripped the door off to pull the man out.

Regnier remembers his hands hurting from cuts he sustained while tearing off the car door, but he doesn’t know what happened with the driver because he left when the EMTs arrived.

Ripping doors off cars or lifting vehicles from people could be considered hysterical strength. Little medical evidence exists about such cases; most of it remains anecdotal.    

Physicians once believed that the adrenaline that flooded the system caused an extra boost to the muscles, allowing people to be stronger. But that’s not quite accurate. Adrenaline certainly primes the body for emergency action, it speeds up the heart and lungs, dilates the blood vessels and releases nutrients, both of which ready the muscles for quick responses.  

And while the adrenaline fueled fight-or-flight reflex spurs people into action, the body’s entire stress response contributes to superhuman strength. Cascades of enzymes and proteins release, helping people sustain the activity.

“Endorphins are very important,” says Provencio. Our bodies release endorphins when we exercise, providing that “runner’s high.” 

These neuropeptides make people feel good and suppress pain as well as providing people with an extra boost to finish their superhuman task.

“[Endorphins] sort of make the brain available to handle these stressful situations. You focus on the task you are doing,” says Regnier. “The endorphins will have a longer lasting affect.” 

While the body’s stress response enables humans to turn into less angry Incredible Hulks, our emotions truly motivate people to attempt such actions.  In most cases, the rescuers believe the victim will die without help. Take 21-year-old Danous Estenor, a University of South Florida football player, who lifted a car off a 34-year-old tow truck driver pinned under a tire in 2011. He believed Pedro Arzola would have perished without his intervention.

“The people who do these things are really under a lot of stress,” says Provencio. “It really touches them personally.” 

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Alyssa Kramer can say any word backward.

Assyla Remark nac yas yna drow drawkcacb.

The 14-year-old from Poteau, Okla., can flip words around and spit them back out almost instantly -- it took me, on the other hand, like 45 seconds to just write that sentence backwards. 

Thanks to Alyssa's weird mental rewind button, she's become something of an Internet celebrity -- her YouTube video has gotten more than 1 million hits. 

Here's the video that launched Alyssa to mini-stardom.

OK, fine, she is maybe saying "huh?" to buy time when facing some of the longer words -- kaleidoscope, withdrawal, Lamborghini. But still -- impressive, right? Absolutely. But Andrew Levine can easily pu-eno Alyssa.

Levine, a research professor in philosophy at the University of Maryland at College Park, can speak entire sentences backward, in the four languages he knows (that's English, French, German and Italian, if you're interested) and in languages he's unfamiliar with. When asked what's happening in his mind when he speaks in backward gibberish, Levine can't say.

"If this girl is doing it the same way I'm doing it, it's nothing. It's like you're speaking another language," Levine says. "In fact, I think that I am effectively bilingual, in the sense that if you were genuinely bilingual, nothing would be going on in your brain." In other words, Levine doesn't consciously think, "TODAY: Y-A-D-O-T." He's just come to innately understand that TODAY backwards is YADOT, sort of like a person bilingual in Spanish and English knows that the words "today" and "hoy" are different ways of saying the same thing. 

About 30 years ago, Levine experienced a brief, weird brush with fame similar to the one Alyssa's experiencing now: He was a guest on "The Tonight Show" with Johnny Carson and was, he says, "a huge hit in Japan." He was also one of the subjects of a series of studies done back then on backward speech, conducted by Lewis Leavitt and then-graduate student Nelson Cowan.

Leavitt says he was curious whether a knack for reverse speech required an unusually strong memory; instead, they found it seems to require no particular special talents or heightened understanding of the English language. Backward-speakers like Levine seem to have taught themselves to hear each word sound-by-sound (or phoneme-by-phoneme, in academic speak). Alyssa, on the other hand, says she sees the word spelled in her head, and she's able to mentally flip it around and pronounce it.

"Backward speech is one of these things that seems to be an equal opportunity skill," explains Leavitt, who's now professor emeritus of pediatrics at University of Wisconsin, Madison. He illustrates this fact with some brief sketches of a handful of those study participants: a Stanford professor, a woman in the UK's House of Lords, a "German striptease artist." The stripper, incidentally, used to include backward speech in her act, and sent Levine a tape so he could check it out. "The striptease itself wasn't all that interesting, but her facility of backward speech was really quite impressive," Leavitt says.

The point is: Backward speakers come from all sorts of backgrounds, although they do have a few things in common. "They tend to be kids who do very well in school, who are smart and who have a decent-size vocabulary, but they are not necessarily kids who have a spectacular memory," Leavitt says. "So it's a skill that they practice, just like the violin."

Starting at around age 8 and tapering off around 13, kids tend to become interested in playing with language -- they might create their own language or make up one with a friend, or they might play around with backward speech. Most kids move on, but a few stick with it. Around this age, Leavitt explains, kids are getting huge bursts of brain power, while at the same time honing their social skills. That cognitive combo helps explain why this tends to be an age of all sorts of "obsessions," some more useful than others: Justin Bieber, "Twilight," a particular video game. In Alyssa's case, it seems backward speech may have been the thing to take hold.

"It's a combination of new cultural, as well as cognitive, prowess, and that's shown in a lot of their activities. And for some, it's developing certain special interests," Leavitt explains. "If you reflect back on your own childhood, you may even find something you were really into at that time." (A fascinating October episode of "This American Life" explores this idea in greater detail.)

In many cases, the things kids obsess over -- Bieber, backward talk, whatever -- may be helping them figure out where they fit in the world, but most of these esoteric interests aren't exactly going to lead to lucrative career options. Back in the early 1980s, when Levine appeared on TV and in newspapers all across the world, people kept telling him, Get an agent! Start an act!

He stuck with academia.

"It was funny 30 years ago," he remembers, "and if it had led to a career on 'Hollywood Squares' or something, I would've stayed with it." 

Can you (or a friend or family member) klat drawkcab? Brag about it on our Facebook page.

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