https://matteocampagna.com/en/registry/equipment/finger-opening-speed-arrow-flex 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/finger-opening-speed-arrow-flexThe only data come from a shooting robot with a competition recurve bow, built in Japan in 2015 with motorised fingers that open at different speeds, and with the arrow's flexing filmed at high speed. The authors expected the arrow to flex more as the fingers opened faster, and that is not what happened: with the motor at 30, 90 and 150 rpm the peak flexing amplitude is 7.07, 7.44 and 7.23 millimetres, so the maximum sits at the middle speed. Opening the fingers statically, up to the smallest angle at which the string slips away, gives the smallest flexing of all, 6.94 millimetres, eight hundredths of a millimetre from the archer used as a reference, at 6.86. The flexing frequency, by contrast, does not move, between 83.7 and 88.5 Hz in every condition. The differences are a few tenths of a millimetre, only just above the reported standard deviations (between 0.18 and 0.23 millimetres), with only three speeds, no stated number of shots and no statistical test, on a machine: the data say the relationship is not proportional on that robot, not that it really has a peak. A 1997 simulation does not vary the opening speed: it says only that in the model the sideways push the arrow receives matters more than the exact way the string leaves the fingers.claim:velocita-apertura-dita-flessione:revision:2026-01-16:3Fri, 16 Jan 2026 08:00:00 GMT https://matteocampagna.com/en/registry/equipment/finger-opening-speed-arrow-flexclaim:velocita-apertura-dita-flessione:new_claim:2026-01-08:riportatoThu, 08 Jan 2026 08:00:00 GMT