Aug 18, 2012

Handedness


In my last post I talked about overuse injuries. On a somewhat related topic, I wanted to discuss briefly handedness. Most of us are right-handed. By most of us, I mean all mammals (if not also even the larger animal kingdom including birds, lizards, amphibians, insects, etc.) are right-handed. Researchers have observed animals, such as hunters, having a dominant paw/hand with which to grab hold of prey, be it a cheetah or a chimp. Even killer whales have been observed to have handedness, but instead of hands, or even fins, most killer whales will attack their prey with the right side of their jaws. This fact has been deduced by examining the bodies of orcas that have washed up on shore - the majority have dominant scarring on the right side of their mouths, presumably from their prey fighting back.

Why handedness? Why not use both hands equally? One common explanation is straight out of a modern economics text: a dominant hand is a physiological expression of specialization. Extending the theory to our hands, if you have two hands and do all tasks equally with either hand, then your accomplishment of tasks will be mediocre, or average. But if you allow one hand to dominate, to become specialized, then it can excel at tasks that require either extra dexterity (dexter coming from the latin for 'right') or strength, or both. 

In the uniquely upright human body, our handedness goes beyond just a dominant arm and hand - it usually amounts to a full-body spiraling affect, usually starting in the hips, if not even in the legs and feet, and just to make things fun, the body will throw in some counter-rotation, often masking the underlying primary rotations. In a word, we are all a bit lopsided, one way or another. But with this lopsidedness comes heightened skill, and thus, more likelihood of success, be it catching a fish in your mouth if you're a porpoise or sticking a forkful of food in your mouth or writing a birthday card to your grandma if you're a homo sapien.

Homework: Just for kicks, try walking 'left-legged'. Walking seems like it would be a pretty even-footed endeavor, but actually if you are right-handed, you likely walk with a dominant right step. Try walking for a block with your left leg being the dominant limb. When I do this exercise, it takes a bit of concentration, even just the minute it takes to traverse a block. I also feel like my hips straighten out, comparatively, though I don't notice them being crooked when I walk normally. And I can feel my torso lengthen as my deep core muscles (in this case, the psoas) become more evenly engaged. Even better, when I think and run left-legged, my poky jogger's pace actually increases, without any extra effort, other than the mental concentration on my left leg. That, I think, is pretty darn cool.  

1 comment:

Jason Dennington said...

So, with your economics analogy as pertaining to specialization, I have a question. If we specialize to take advantage of a dominance in one area, such as developing a work efficiency or economy of scale, theoretically there would be some areas the right would excel at and others dominated by the left. How could we enhance the areas our overall weaker side is favourable in to disperse the workload and encourage each side to be more equal partners?