The best way to know if your arrow spine is too stiff is to shoot a video of the flight of your arrow. Watching the flight of your arrow will let you see if your arrow is swerving to the right or the left. If your arrow is veering towards the right, it is too weak, and shifting towards the left means it is too stiff. Based on what you see in your video, you can take steps to correct the direction of your arrow during flight. Archers call the process of restoring a bad arrow flight “arrow tuning.” An over-spined arrow usually veers off-target as it loses energy and velocity. Meanwhile, an under-spined arrow is a weaker or less tense that causes it to wobble and stray off-course. Moreover, an arrow with a soft spine flexes more manageable than an arrow with a stiff spine. If the arrow flexes too much or if it does not flex enough, it will indeed not fly straight. Another thing to know about an arrow spine is that if the arrow’s spine is too stiff or weak, the arrow will not correct itself while in flight. Once the arrow is super stiff, it will not follow the path that the archer intends causing a missed target or less accuracy. Thus, optimizing your arrow’s flight is the key to accuracy. When your arrow wobbles less, it will straighten out and fly in a straight direction towards your target. However, when your arrow flies straight, it does not lose its energy to the wobbles and will get its maximum force into the target you want to aim for. To assess a spine rating, manufacturers use the two widely known and recognized standards of measurement in archery: the American Society for Testing and Materials (ASTM) and the Archery Trade Association (ATA). Each organization has similar testing methods for determining a spine rating. For the ATA test, they will attach an arrow to two supports 26 inches apart. They will then press the middle of the arrow with something that weighs at least two pounds or 970 grams. Depending on the result, the deflection in the arrow will show its spine rating. The ASTM does the same process. But the only difference between these two processes is that the ATA rating is primarily for wooden woods, while the ASTM test is for slightly used carbon fiber arrows or aluminum construction. If you want to do the spine test yourself, you can buy your measuring equipment, test the arrow’s spine, or make the spine tester yourself. To make a spine tester, you must set up your measuring tool at home. However, if you are not keen on using the DIY spine tester, you can take your arrow spine to an archery shop and let the professionals do it. Archery shops have a spine tester on-hand, and they will be able to determine quickly the condition of your arrow spine by just looking up the name of the manufacturer and the arrow’s name.