Arrow spine is the stiffness of the arrow, measured by how much it deflects (bends) under a standard test. A lower spine number means a stiffer arrow (e.g. 300 spine is stiffer than 600 spine). The paradox of archery — that an arrow bends around the bow before straightening — requires matching the spine to the draw weight and arrow length. An underspined arrow (too flexible) flies left for a right-handed archer; an overspined arrow (too stiff) flies right. Point weight, bow type and arrow length all affect the required spine.
Key points
- Lower number = stiffer spine
- Must match draw weight and arrow length
- Underspined flies left, overspined flies right
- Point weight, bow type also affect selection