XXXX and fluid needs of the soccer player.

@entity948 @entity2690 @entity413 @entity1735
Soccer is a game that demands a combination of repeated maximal sprinting wit with 10 to 11km of moderate running, sometimes performed under extremely warm conditions. Over the course of a match, there is partial to near complete depletion of glycogen reserves in the leg muscles (depending on the extent of initial reserves and the level of competition), with a resultant decrease in physical performance. Blood @entity413 levels also fall, sometimes to values likely to cause a deterioration of both tactical thinking and cooperation between players (3.0 to 3.8 mmol/L), while in tropical climates, fluid losses can amount to 4 to 5kg of bodyweight. The effectiveness of @entity413 solutions in correcting these problems is limited for 2 main reasons: concentrations greater than 2.5% slow the rate of gastric emptying and thus fluid absorption, while provoking a secretion of @entity2690 with a resultant hypoglycaemia. @entity948 solutions are less liable to increase @entity2690 secretion, but they have an equal propensity for slowing gastric emptying; moreover, the ingested @entity948 is largely metabolised in the liver, without boosting blood @entity413 . However, @entity413 polymer preparations have a low osmotic pressure per unit content of @entity413 equivalent, so that substantial amounts of @entity1735 can be administered in this fashion before gastric emptying is inhibited. If polymers are given before and during a soccer game, they sustain blood @entity413 , sparing muscle glycogen stores and increasing game performance. If the concentration of polymer is too high, one possible complication is a movement of water from the plasma into the gut; nevertheless, with an appropriate choice of concentration (for example, 7% polycose, 360 mOsm/L, plasma volume is increased rather than decreased relative to that seen with administration of water. Probably because the intergame interval for competitive soccer players is short, replenishment of glycogen reserves proceeds quite slowly. Moreover, this process does not seem to be helped by ingestion of either @entity413 polymers or a high @entity1735 diet.
