Thursday, April 9, 2009

How strong are we?

There has always been anecdotal evidence that under certain circumstances humans can perform fantastic feats of strength. I have long wondered whether this was true and, if so, how we might better tap into that strength. It was in that light that I read this news item, about scientists who think chimps are stronger than humans because our muscles are under tighter cerebral control:
February's brutal chimpanzee attack, during which a pet chimp inflicted devastating injuries on a Connecticut woman, was a stark reminder that chimps are much stronger than humans—as much as four-times stronger, some researchers believe. But what is it that makes our closest primate cousins so much stronger than we are? One possible explanation is that great apes simply have more powerful muscles.

Indeed, biologists have uncovered differences in muscle architecture between chimpanzees and humans. But evolutionary biologist Alan Walker, a professor at Penn State University, thinks muscles may only be part of the story.

In an article published in the April issue of Current Anthropology, Walker argues that humans may lack the strength of chimps because our nervous systems exert more control over our muscles. Our fine motor control prevents great feats of strength, but allows us to perform delicate and uniquely human tasks. . . .


Thomas said...

I don't know about the limits of human strength, but I read a really interesting article about baseball pitchers last year which discussed the limits of pitching speed. Apparently, the limiting factor in pitching speed is not muscles but ligaments - pitchers essentially can't throw much faster than 100 MPH without blowing out their shoulders. No amount of adrenalin or muscles can change that.

John said...

But it takes years of training and a fair amount of talent for a pitcher to come up against that limit. I doubt a normal, fit, but untrained sort of person can throw a baseball more than about 40 miles per hour, so the training is producing a doubling or more of the power produced. And I bet a lot of the increase comes from reducing the pressure exerted by the muscles that would normally be opposing the throwing motion. I read that in an old article about throwing a javelin -- what javelin throwers learn is as much about turning off certain muscle groups during the throw as increasing the output of others. This fits into the notion that we are limited by the need for control. Our bodies are set up with muscles in opposing pairs, and if you try to carefully control the motion of your hand you are using the opposing muscle pairs to pretty much the same extent. Generating extreme effort requires letting go of the control.