Okay, I'm familiar with the idea of crewmen on yachts leaning and moving, particularly when turning - images of several of them with their feet on the edge (right term?) of the boat, their entire weight leaning out over the water as they hold onto ropes, come to mind. But believe me, if the idea wasn't familiar to me, I'd certainly ask our resident commodore all about it"Dynamic positioning of mass" means that the crew lean in on curves. In yacht racing, crewmen are picked for their size because they can then affect the stability by moving about. Ask AN for further details.
But I wouldn't have thought that that would apply in bobsledding since all the curves are banked. If you're riding a motorbike and you turn left, then you lean left and the bike tilts to the left. But in bobsledding the sled is tilted to the left by the bank of the snow/ice; you don't need to lean. Or that's how it seems to me - I'm quite prepared to believe I have it very wrong