Neither am I...

I' m pretty certain static spine refers to the spine in an arrow at rest with no outside influence exerted upon it.

Take golf shafts for instance. Finding the ideal Flex for one' s individual swing is paramount to good repeatable performance. However, spine aligning is the popular rage right now as current technology doesn' t quite allow one to build a shaft without a spine. So, builders align the club head and grip along the " spine" , so it influences flex the same way club to club, hopefully. From there, they vary the flex of the shaft to meet one' s swing speed and dynamic loading of the shaft. Some manufacturers are very close to producing a spineless shaft (like Apache), where the shaft will flex identically no matter how it' s held, but the majority don' t/can' t, apparently.

This get' s into what Arthur was saying, he aligns his cock feathers along the spine, to have the best potential for repeated flex from arrow to arrow within a batch. As long as the shafts flex identically, he should be good to go. If they don' t, he' ll get fliers. Matching flex, particularly if using a fixed rest, is tantamount to tight grouping.

After all of this, I' m pretty certain everyone is right Spine doesn' t move or degrade, but arrow flex changes due to extended use or repeated heavy impact, causing fliers and bad arrows.