https://matteocampagna.com/en/registry/equipment/arrow-natural-frequency-spine Changes to this claim in Matteo Campagna's evidence registry: its status, its year-by-year history, revisions of the page. en-gb https://matteocampagna.com/en/registry/equipment/arrow-natural-frequency-spineThe measurements all point the same way, and mechanics says why: a stiffer shaft, at equal mass, vibrates faster. Three compound arrows from the same series, measured with the shaft free, vibrate at 74, 77 and 80 hertz from the weakest to the stiffest, and a second study with a laser vibrometer finds the same order, 78.3, 80.2 and 83.3 hertz. An independent group, with carbon, aluminium and cedar shafts, finds the stiffer spine higher in every material, with one pair where the difference lies within the uncertainty. The status stays reported for three reasons. The two most precise measurements come from the same group and the same arrow series, and the third study is a course project with an uncalibrated rig. In no test does spine change on its own: the stiffer shafts are also heavier, and the only comparison that varies stiffness alone, plus 20 per cent with the frequency going from 85.4 to 95 hertz, is calculated with a model. Finally, the step from one spine to the next is worth a few hertz, less than 3 per cent, and a more powerful bow lowers the arrow's frequency during launch: nobody has shown that measuring it helps in choosing the shaft.claim:frequenza-freccia-spine:revision:2026-03-17:2Tue, 17 Mar 2026 08:00:00 GMT https://matteocampagna.com/en/registry/equipment/arrow-natural-frequency-spineclaim:frequenza-freccia-spine:new_claim:2026-02-09:riportatoMon, 09 Feb 2026 08:00:00 GMT