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WORLD CUP 2022: OPTIMISING NUTRITION AT INTERNATIONAL FOOTBALL TOURNAMENTS FEATURE / DR. JULIEN LOUIS It is well established that diet affects physical and mental performance of football players. Foods and beverages players choose in each meal and snack will influence their adaptation to training, their performances in match, and their ability to recover and reach their maximal potential. The team nutritionist should be aware of the nutritional requirements of performance in football so that food can be made available and bespoke nutritional strategies be implemented on a daily basis. Because every player is different, nutritional strategies for the team should also be adapted to individual training load, engagement in match (e.g. starters vs. non-starters, minutes played), positional roles, and individual characteristics such as anthropometry, food intolerance/allergy, preferences as well as philosophical or religious beliefs. These considerations are all the more important during an international tournament because of the increased physical and mental load put on players. As such, in this article we propose a series of practical advice that we hope will help practitioners to design and implement their team nutritional strategy for the next world cup in Qatar. We will purposefully focus on what we consider the top nutritional priorities for an international tournament, which are: preparing for match play (training and recovery days between matches), and peaking on match day (pre, during and post-match). Although a food first approach is favoured, we will also review the dietary supplements that present an interest during the competition. Finally, we will draw a list of practical recommendations.
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Preparing for the match Match play in elite football is characterised by a variety of intermittent activities including walking onwards and backwards, changing direction, sprinting, jumping, striking the ball, and some contacts with opponents. Although low-intensity activities such as walking account for more than 70% of the duration of the games, they are interspersed with 150–250 short but intense actions which increase the metabolic demands. As such, the average relative intensity of a game represents 70% of maximal oxygen uptake, equating to an energy expenditure of 15-20 kcal/min or 1350-1800 kcal per match, in which carbohydrates (CHO) contribute to 60-70% of the total energy supply (Bangsbo et al. 2006). We also know that muscle glycogen stores (the form of CHO storage in the muscles) are depleted by ~50% after match play (Krustrup et al. 2006), which could be responsible for the decrease in performance (less distance covered, less highspeed running) classically reported in the second half (Mohr et al. 2003), along with other factors such as dehydration (Mohr et al. 2010), muscle damage (Krustrup et al. 2011), and mental fatigue (Smith et al. 2016). National teams competing in the next world cup will play between 3 and 7 matches (depending on their progression through the competition) in 4 weeks, which corresponds to an average of 1 match every 4 days. In this configuration, preparing for the match mainly consists in optimising recovery and activation sessions
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between matches, leaving limited room for training for players who will play most games. Accordingly, energy expenditure is expected to fluctuate throughout the week according to the training schedule around matches. Therefore, the team nutritionist should liaise with coaches to ensure that dietary intake meets the demands of recovery days (low energy expenditure), training days (higher energy expenditure), and match days. Most importantly, because CHO are the primary fuel of performance in football, their intake should be periodised day-by-day and meal-by-meal according to the demands of the previous session (to allow recovery and adaptation) and that of the next session (to allow energy storage). A traffic light colour coded system can be used to facilitate the implementation of a periodised CHO dietary strategy throughout the days and weeks of the tournament (figure 1). For example, on recovery days with no training session CHO intake should be in the moderatemedium range (4-6 g/kg Body Mass, BM/day, amber colour in table 1), whereas on training days and the day before the match it should increase to a higher range (6-8g/kg BM/day, green colour in table 1) to promote glycogen storage. A low CHO diet (< 4g/kg BM/day, red colour) should not be implemented at any time during a period of congested fixtures such as a tournament to avoid inadequate glycogen storage before matches (Collins et al. 2020). Match day -Before match play- In match, performance is dependent on the amount of glycogen stored in the muscles and liver at the start of the game, exogenous CHO availability during the game, the hydration status, and gastrointestinal comfort. Accordingly, the pre-match diet (including breakfast, and/or last meal or snack) should meet these priorities. First, a high CHO diet the day before (6-8g/kg BM) should allow footballers to begin the match with high glycogen stores (Anderson et al. 2016). In the morning prior to the match, breakfast should include a medium-high (≥ 2g/kg BM) CHO intake according to the players’ appetite and preferences in order to optimise liver glycogen resynthesis, which can be reduced by up to 50% following the night (Nilsson et al. 1973). The last meal or snack should be served 3-4h before kick-off, with ~2g CHO/kg BM. Normal protein (PRO, 1.5-2g/kg BM/day evenly distributed