If you can't manage the physical kind*, at least strive for the mental kind. It will make your life easier, not to mention a lot more pleasant for those around you.
Mental suppleness is essential in a storyteller. For the rigid, a trip down the Great What-If Path is pretty monotonous. Loosen up, and the scenery gets infinitely more fascinating.
Which is why I've adopted what DD tells me is the unofficial motto of the Navy:
That translates loosely as "Always Flexible!" (Because, you know, Gumby was the most flexible little dude ever.) A necessary quality when you're in the service, and can be whipped around the world at a moment's notice. But I find it also holds me in good stead whenever I sit down in front of the keyboard and try to create a story out of the chaos between my ears.
*For instance -- and I know this will be difficult for you to believe, but trust me, it's true -- that is not me in the picture above. Not that I couldn't get into that position if I wanted to. I could. But it would require a trip to the emergency room to get me back out of it.
Oops. Almost forgot the obligatory ending question that (who are we kidding?) is meant to inspire comments, so we don't feel like we're talking to an empty room:
Are you as flexible as you'd like to be?
Or, alternately, if that question is too personal:
Did you watch Gumby as a child? (If that's too personal, I respectfully suggest you, um, Gumby up a little.)