Physiology and nutrition in archers: Oliveira 2021

This master's thesis brings together two studies on the same 8 archers from the Brazilian national recurve team, 4 men and 4 women. In the first, the author compared a simulated competition of 144 arrows, 36 at each distance (90, 70, 50 and 30 metres), with a rest day, taking the same measurements at the same times. On competition day blood lactate rose after every distance, with means between 2.8 and 3.3 mmol/L against about 1.5 at rest; blood glucose fell significantly only after the 70 metres, to around 3.5 mmol/L against 4.6; perceived exertion on the CR10 scale reached between 2 and 4 points, against values close to zero on the rest day. These values can only be read off the graphs. Salivary cortisol was higher in the morning, with the only difference from rest marked after the 70 metres, and dropped in the afternoon; salivary IgA and grip strength did not change significantly. The author concludes that the simulated competition shifts these markers, but only slightly.

In the second study the archers attended six weekly sessions of nutrition education, five one-hour talks and an individual consultation with a nutritionist, with two half-competitions at 70 and 90 metres, one before and one after. After the programme the men ate more at breakfast (protein p = 0.037, carbohydrate p = 0.030, fat p = 0.031) and more carbohydrate in their snack (p = 0.047); the women had increased only their breakfast protein (p = 0.009), which on the graphs goes from about 4 to about 17 grams. In the second half-competition blood glucose was higher at all three measurement points, already at rest before shooting (about 5.1 mmol/L against 3.6), while cortisol did not change.

The archers were members of the national team training in Campinas; the thesis gives no ages, draw weights, scores or result for the simulated competition. In the first study blood glucose was measured with a portable metre, lactate on 25 μl of earlobe blood with a YSI 1500 Sport analyser, and cortisol and IgA on saliva samples collected after an overnight fast and analysed with Salimetrics kits. Grip strength was the best of three 5-second attempts with the dominant arm, and perceived exertion came from the CR10 scale after each series and 30 minutes after the end. Samples were taken before the competition and after the series at each distance, with saliva at four times of day: 8 am before the 90 metres, noon after the 70, 2 pm before the 50 and 5 pm after the 30.

In the second study eating habits were recorded with a food frequency questionnaire and a three-day diary limited to breakfast and snack, filled in before and after the programme. The talks covered nutrients, meal timing in relation to training, recipes and strategies for sticking to the plan, hydration and supplements. The athletes were not told in advance that samples would be taken at the two half-competitions, so that they would not change what they ate on those particular days. The statistical analysis section is empty in both studies and the results appear only in graphs, with significance letters that the text does not explain.

Eight archers is a small group, and for grip strength it becomes four per sex. Neither study has a control group. In the first, the competition is compared with a rest day, not with a training session of the same volume without competitive pressure, so the effect of shooting 144 arrows cannot be separated from that of being assessed, as the author acknowledges. In the second the comparison is before and after, with everything that can change in six weeks, and blood glucose was already higher before any shooting: the difference therefore concerns the starting state on the day, not how glucose holds up during the half-competition. The thesis summary mentions a comparison with a training session that does not appear in the methods.

The numbers can only be read off graphs, with no tables, and the statistical method is not described. Text and figures do not always agree: cortisol is reported as rising after every distance, while the graph marks a difference from rest only after the 70 metres. Nutrition knowledge, which the author believes improved, was not measured, as he himself admits. Finally, the thesis reports no scores, so there is no way to tell whether anything changed in the shooting, and the work did not go through peer review.

For archers, the first study gives an order of magnitude for the physical cost of a 144-arrow day over four distances: lactate stays below 3.5 mmol/L, perceived exertion at the middle of the scale or below, and grip strength shows no significant drop. These are values typical of light effort, and the author himself describes the effect as small. The fall in blood glucose after the morning session, to around 3.5 mmol/L after the 70 metres, is the finding that links the two studies: no value went below the threshold for hypoglycaemia, but this was eight athletes and, in the second study, half-competitions.

The second study shows that six sessions of nutrition education changed what these athletes ate at breakfast and in their snack, more in the men than in the women, and that after the programme blood glucose on competition day started higher. Before the sessions, in a national team without a nutritionist, breakfasts were light: the women, judging by the graphs, took in about 4 grams of protein. The study does not show that eating better leads to better shooting, because shooting was not measured: it only documents that in a high-level group the morning diet was some way from the one the same athletes adopted once they had been informed.