Isotonic drinks and archery score: Qolbi 2026 study

Twenty Indonesian university archers shot on two consecutive days, drinking an isotonic beverage on one and mineral water on the other, to see whether the score and hydration status changed. They were 8 men and 12 women, half shooting recurve and half the standard bow, aged 20.4 on average, with 5.75 years of practice and almost four training sessions a week.

The median score was 560.5 points with the isotonic drink and 551.5 with water, out of a maximum of 720: a nine-point difference that the test cannot separate from chance (p = 0.070). The two distributions overlap widely, from 505 to 663 points with the isotonic drink and from 508 to 647 with water.

On hydration the picture is more layered. Urine specific gravity started at a median of 1.025 on both days, a value that indicates a fluid deficit, and fell to 1.020 on both. Within the isotonic day the reduction was statistically detectable (p = 0.001), with 15 archers out of 20 going down; within the water day it was not (p = 0.088), with 11 going down, 7 unchanged and 2 going up. Comparing the two changes directly, however, the difference disappeared (p = 0.062) and the median change was identical, minus 5 in both conditions. The authors themselves set out the reasons: twenty participants, reagent strips with coarse steps that produce many identical values and so weaken the test, and a final measurement taken immediately after shooting finished, before rehydration has had time to show up in the urine. A side finding is that these archers' habitual fluid intake was 1,918 ml a day, below the national recommendation of 2,350 to 2,500 ml for their age group, and that only three of the twenty habitually drank isotonic beverages.

The study is a quasi-experiment with a crossover design: every archer did both conditions, so each serves as their own control. The two sessions were held on 7 and 8 February 2026 at a range in Surabaya. The population was 30 athletes from the university club, of whom 20 met the criteria: recurve or standard bow division, aged 18 to 23, at least three training sessions a week and a regional or national competition in the past year, with no acute injury and no condition affecting fluid balance. A power calculation in G-Power, set for a large effect, called for at least twelve participants.

The order of the two drinks was assigned by odd or even number on the attendance sheet rather than at random. The drinks, a commercial isotonic beverage and a commercial mineral water, were served in dark paper cups of the same volume to keep the archer unaware of which one they were drinking. In each session 150 ml was given every 10 minutes from the warm-up to the end of the scoring round, for a total of 1,050 ml.

Scores were recorded on the international federation's scoring sheet, on an 80 cm face at 30 metres: two rounds per session, each of six ends of six arrows, so 72 arrows and a maximum of 720 points per condition. Urine specific gravity was read with reagent strips on a mid-stream sample, before and after each session. Training duration and timing, environmental conditions, fluid taken outside the protocol, food, caffeine and strenuous activity in the preceding 24 hours are all listed as controlled variables. Almost every variable departed from a normal distribution on the Shapiro and Wilk test, and a logarithmic transformation did not fix it, so the comparisons were made with the Wilcoxon signed-rank test for paired data.

Twenty archers, two days, no external control group: at this size only a large difference would have shown up, and the power calculation was indeed built on a large effect. The order of the drinks was not randomised but assigned by odd or even number, and the two sessions fell on consecutive days, so the second day carries the first day's shooting with it. The blinding covered the colour of the cup: the taste of an isotonic drink remains recognisable, and nothing can be said about the athletes' expectations.

The measuring instrument is the declared weak point. Reagent strips have coarse steps and produce many identical values, which the Wilcoxon test treats as ties and which the authors name as the reason for the lack of significance; the final measurement was taken immediately after shooting ended, too early for the fluid drunk to show up in the urine. Specific gravity, which is a ratio with no unit, is reported throughout the paper as though it were a concentration in grams per decilitre, and a median of 1.025 is described as severe dehydration, whereas a value like that is usually read as a mild to moderate fluid deficit.

Several things an archer would care about are left out. The temperature and humidity of the two days are not reported, although they are listed among the controlled variables. Scores come from 30 metres on an 80 cm face, a short distance for a recurve, and there is no intermediate measurement that would show whether the score drifted down over the session. Nobody measured sweat loss, body mass or anything else: the only hydration marker is the urinary one.

On the question the study starts from, whether an isotonic drink is worth having instead of water during training, what can be drawn from it is that over 72 arrows at 30 metres the measured difference was nine median points and cannot be separated from chance. Nine points out of 720 is small in practical terms too, and with twenty archers and a single session per condition the comparison can neither rule out small differences nor establish them.

The more telling figure has nothing to do with the drink and everything to do with habit. These archers arrived on the field with a median urine specific gravity of 1.025 on both days, and drank an average of 1,918 ml a day, below the recommendations the paper cites for their age group; in their preliminary observations the authors report that in training the athletes drank about 750 ml over two hours. In other words the margin lay in how much, before what, and the two conditions of this study differed only in the what, since the volume was identical at 1,050 ml in both. The study measures no effect of starting with a fluid deficit on performance, and it should not be read as guidance on how much or when to drink: it describes two days of shooting at an Indonesian university club, on an 80 cm face at 30 metres.