Yes Brett, the old "rule" was that the shutter speed should be the reciprocal of the lens length to avoid shake. Complicated these days if using a NON full frame by magnification of 1.5 or 1.6. That makes the effective length of a 600mm lens (at full zoom) approx a 900mm or so. Hence under old folk lore, need a shutter speed of around 1000th of second.
As an offset of course, anti shake seems to work quite nicely these days
Tripods certainly help with long lenses
If getting extreme, mirror lock up, remote shutter release all help to remove shake out of the process.