I'm a good bassist and have made a living at it for years now, but one thing that has always bothered me is my lack of speed. I am OK with speed, but not for very long, and I've had people tell me it's because I tense up my right arm when the tempos get fast. Well how the heck do you not? And yet, I watch all manner of bassists not tense up their arm when the going gets fast, and I just don't get how they do it. What am I missing?