https://matteocampagna.com/en/registry/equipment/bow-efficiency-energy-to-the-arrow 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/bow-efficiency-energy-to-the-arrowThe three-quarters figure starts out as a modelling parameter and only later finds a measurement. In 1990 the reference model for the competition recurve sets the efficiency at 0.75, meaning three quarters of the drawing work becomes kinetic energy of the arrow; the following year another model of the modern working recurve calculates it instead of setting it and finds 0.729, and in 1998 a more complete model takes up the same value, recalls that estimates fitted to filmed shots give 0.76 longitudinally and 0.71 transversely, and reports that on a modern bow the measured efficiency was a few points below the prediction. The first measurement on a bow shot by archers comes in 2001 and concerns kyudo: with ten archers and fifty shots per string, the Japanese bow passes between 67.7 and 69.4 per cent of its stored energy to the arrow. On a modern bow there is a single measurement, from 2015, in a preprint and on a compound the paper does not describe as a competition bow: the archer puts 73.7 joules into the draw, the bow gives back 71.0 and the 20.6 gram arrow receives 57.1, a little over three quarters of the drawing work and 0.80 of the energy returned. The order of magnitude holds, but the figure depends on how it is defined, against the drawing work or against the energy the bow gives back, and on the arrow, since the same bow is more efficient with a heavier arrow. For a competition bow, and for today's Olympic recurve in particular, there is no direct measurement.claim:arco-efficienza-trasferimento:revision:2026-04-10:3Fri, 10 Apr 2026 08:00:00 GMT https://matteocampagna.com/en/registry/equipment/bow-efficiency-energy-to-the-arrowclaim:arco-efficienza-trasferimento:new_claim:2026-03-23:trasferitoMon, 23 Mar 2026 08:00:00 GMT