Holding Bow Digitec Test for archers: Prasetyo 2022

This conference paper takes up the Holding Bow Digitec Test device and the same 33 adult archers (18 men and 15 women, students aged 20 to 23) as the longer paper the same authors published that year, and concentrates on the validity and reliability figures. The device measures arm strength in kilograms and holding time in seconds; it weighs 2.9 kilograms, which the authors set beside the range of 2.5 to 3.5 kilograms they give as the usual weight of a bow.

The tables are the same as in the other paper. On strength the digital device gives a maximum of 25 kilograms, a minimum of 14 and a mean of 18.18, the manual test 25.4, 14.5 and 18.54; on holding time the digital device gives 24, 15 and 20.34 seconds, the manual test 24.4, 15.2 and 20.48. Between the two measures the correlation is 0.939 for strength and 0.974 for holding time, with significance below 0.001.

The figures this paper adds are four: a validity of 0.961 for strength and 0.895 for holding time, compared with a critical value of 0.344, and a Cronbach's alpha of 0.978 for strength and 0.944 for holding time, compared with a threshold of 0.60. What those two validity coefficients are is never stated: the text does not say against which criterion they were calculated, and the values do not match the digital-to-manual correlations reported a few lines above.

The 33 archers come from the Yogyakarta university club and the Klaten provincial association; measurements took place at the Yogyakarta student training centre, with data collection spread between March 2018 and July 2019. The design is research and development following Borg and Gall's ten-step model, with content validity assessed through Aiken's V, concurrent validity through Pearson correlation and reliability through a test-retest.

The method section of this paper is very short, and part of it is left in Indonesian in a text published in English. It contains no test protocol: there is nothing on what resistance the archer works against, how the draw is taken, when the hold is considered finished, how many attempts are allowed, how much rest there is between them, or how much time elapsed between the two administrations of the test-retest. Of the device itself this paper reports only the weight: the technical description (the 24-inch riser, the calibrated spring, the load sensor, the microcontroller, the memory, the USB port) is in the other paper. It is not stated who took the measurements, or whether the manual and the digital measure were taken at the same time or in separate sessions.

This is a publication on the same data as the same authors' journal article, and the link is recorded: in the registry's claims the two papers count once. Set side by side, though, their numbers do not line up. Reliability here is a Cronbach's alpha of 0.978 and 0.944, while in the other paper the method and the tables report a test-retest with Pearson correlation and no alpha; and two validity coefficients appear here, 0.961 and 0.895, with no statement of what they are calculated between. An alpha of 0.978 on a test made of only two measures is in any case a value that calls for an explanation, and the explanation is not given.

The limits the authors state are the sample of 33 people, measurements in different places and at different times with athletes in varying condition, and the fact that the device is intended for adult archers only; they add that reference norms remain to be built. To these should be added that the validity demonstrated is a comparison with the manual version of the same exercise, not with shooting performance: no arrows, no scores, no link with accuracy. The significance threshold is written as 0.005 instead of 0.05, and a value of 0.330 appears in the text that comes from no calculation shown. These are, finally, conference proceedings, with peer review not stated.

For an archer the useful content is the weight of the device: 2.9 kilograms, chosen to fall inside the range the authors give for a competition bow, so that holding it resembles holding your own bow. That is the part that makes the test specific, and it is easy to see why it is needed: measuring a hold with whatever bow is to hand changes the test every time the draw weight changes.

What remains is that the figures in this paper are measures of the device, not of the archer shooting. They say the instrument repeats itself and agrees with the manual version of the same exercise; they do not say how much strength or how many seconds are required, or that an archer who holds longer scores more. In the registry this record mainly serves to document the figures quoted by the Indonesian studies that use the Holding Bow Digitec Test as a measure of arm endurance.