Soccer playing involves intermittent exercises the physical intensities of which depend upon the player line up in the field, the importance of the game, and competitor excellence. This review aims at describing the major metabolic impacts on these physical efforts and their nutritional implications for performance purposes. Soccer players usually spend approximately 1360 kcal each game, with a 5% decrease in the second half of the game. Glycogen reserves modulate strength and length of movements. Elite players deplete from 20% to 90% of their glycogen level during a match according to their physical conditioning, exercise intensity, environmental temperature, and pre-competition dietary intake. Body dehydration and hyperthermia accelerate glycogen depletion and fatigue, a process that can be observed in particular on the second half-time, when players avoid sprints, walk more than run and reduce the accomplished distance. Hence, water and carbohydrate supplies are the major nutritional ergogenic elements for soccer players. Since soccer games have only one interval, athletes are not provided with cyclic water reposition. So it is advisable that athletes are given 500 ml of liquid containing either glucose or polymers at 5% to 8% half an hour before the beginning of the game. Better performances are observed with intake of 312 g carbohydrate diets 4 hours before the game and with replenishment of glycogen stores by providing athletes with 7-10 g carbohydrate/kg/24h after the game, mostly in the first two hours after the game is over. Another nutritional risk regards athletes' micronutrient status, which results from muscle wearing, intestinal losses, intense sweating, frequent trips, and changing menu. But in the case of soccer players, the unbalanced diet seems to be related to a higher intake of protein and fat, as well as alcohol, and a lower intake of carbohydrates.
Soccer; Metabolism; Energy; Nutrients
