Scientific American has an interesting short piece on whether people can really demonstrate super-human strength in emergency situations. The typical story is where someone is trapped under a car after an accident and a friend or relative manages to lift a seemingly impossible weight to free them.
This common tale has all the hallmarks of an urban myth, but it turns out to be partially plausible. Fear seems to increase our available muscle strength – but not by super-human amounts – only by a fraction of our normal lifting power.
Vladimir Zatsiorsky, a professor of kinesiology at Penn State who has extensively studied the biomechanics of weightlifting, draws the distinction between the force that our muscles are able to theoretically apply, which he calls “absolute strength,” and the maximum force that they can generate through the conscious exertion of will, which he calls “maximal strength.” An ordinary person, he has found, can only summon about 65 percent of their absolute power in a training session, while a trained weightlifter can exceed 80 percent…
But there’s a limit to how fast and how strong fear can make us. We’ve all heard stories about panicked mothers lifting cars off their trapped babies. They’ve been circulating for so long that many of us assume that they must be true. Zatsiorsky’s work, however, suggests that while fear can indeed motivate us to approach more closely to our absolute power level than even the fiercest competition, there’s no way to exceed it. A woman who can lift 100 pounds at the gym might, according to Zatsiorsky, be able to lift 135 pounds in a frenzy of maternal fear. But she’s not going to suddenly be able to lift a 3,000-pound car.
The SciAm article is apparently an excerpt from a new book entitled Extreme Fear: The Science of Your Mind in Danger.