Tuesday, June 12, 2012

Why "just do it the other way" is not sufficient

So way back when in my volleyball days, we had a few lefties on our team that ended up playing kind of "weird". Some of them would switch and play right-handed, and some would just do things really strangely. I remember a particular instance where our coach instructed us on how to "approach" before a spike, which is a distinctive runway/windup procedure that started with the left foot and ended with the feet at hip distance with the left foot slightly ahead, and our right arms ready to take a swing. The goal was to get the maximum amount of torque force initiating from the left oblique abs so not all the load force of contacting the ball was directed into the right arm (sorry, former biomechanics research-speak taking over!); this "approach" is essential to decrease the incidence of torn rotator cuffs and dislocated shoulders. The coach even impressed upon us how important it was to not just jump from a static standing position. So when the coach finished his instruction for us righties and said, "and you lefties, just do it the other way"...that didn't really seem sufficient.

The truth is, no matter which is your dominant hand, your "handedness" or "sidedness" is in no way interchangeable or transferable. Many vital functions of your brain "live" in one hemisphere and not the other (e.g., Broca's and Wernicke's areas, which are responsible for speech production and speech processing, respectively, live in the left frontal and temporal lobes). The motor regions of righties light up more on the left side of the brain in brain scans (motor control for each side is "contralateral", meaning that it resides on the opposite side)...but more about that later. And this extends to the rest of your somatic (i.e., bodily) organs as well. Your heart cheats a little left-of-center, with with the right and left chambers responsible for different functions, and many of your other organs (liver, spleen, pancreas, stomach) reside more on one side than the other. So why the expectation that, in physical (and cognitive) activities, you can just switch?

Now, of course, we can't overlook the plasticity of the brain in this matter. Sure, stroke victims can "retrain" their brains so that essential functions in their non-functioning hemispheres can "live" on the other hemisphere, and "split-brain" patients who have had the connective tissue between hemis severed to decrease seizures often have (near-) equivalent functioning brain areas appear on both sides of their brains. Also, presumably because they've been raised in a righty world, the motor regions of lefties light up in brain scans on both the right and left side (had the righties been raised in a lefty world, the reverse would probably be true).

So with all this talk of plasticity and such, why can't you just strike that and reverse it? Context. Your body "learns" things without you even being aware of it and holds onto this knowledge even if you try to forget it. It embeds subtle differences in skin stretch, pressure, force, and any number of things into this memory so it's  in there unless it's untrained through competition, not training/practicing the memory, or letting it fade over time. There's some discussion over whether simple tasks like reaching can transfer between sides (I've read the studies, but these studies are so tricky to design that it's difficult to tell WHAT is transferring), but with things as complicated as the volleyball approach, playing a scale on the cello, or learning a new dance step, I'd say no until someone incontrovertibly proves me wrong (and, believe me, I'd love them to. Then we could learn 1 thing and be set for life.) So when you see something demonstrated, try it, and then attempt to transfer it to the opposite side, you're not likely to be successful. When you practice a musical scale on a cello with a particular fingering all the way up the fingerboard and then that fingering changes after 8 octaves? Nope. When you've only practiced a dance step right, left-right-left, good freaking luck with left, right-left-right.

And again, I'm going to bitch about how brains/bodies are awesome and freaking annoying at the same time. In fact, that could practically be the unofficial title of this blog.