It is common for football clubs to begin their pre-season training during the hot months of November and December to fully prepare for the upcoming season.
Pre-season matches also begin during the hot months of February to March. Teams are often at their fittest during these months so it is important to maintain this level of fitness when entering the home and away season.
The speed of elite Australian Football (AFL) over the past four decades has doubled, which is putting more physiological demand on the bodies of all players. This demand can be put under more strain in the heat of the summer months when clubs are often training the hardest.
Consequently hydration and recovery become important components during and/or after training sessions to allow teams to perform at their optimum during the next training session and/or match.
It is generally accepted that dehydration and carbohydrate depletion have detrimental effects on physical performance and recovery. However the question, ‘What is the optimal hydration before exercise?’ is often asked when preparing for a match.
Some clubs use the Urine Specific Gravity Testing and Body Weight Testing before and after matches to objectively analyse hydration levels. Urine Specific Gravity testing is a simple test using a portable refractometer and provides immediate feedback to the players in relation to their hydration levels.
Urine colour is commonly used to determine hydration levels, however urine colour can be affected by the ingestion of dietary supplements. Urine Specific Gravity testing gives a true reading of hydration.
A urine sample of 10ml is provided and placed in the refractometer, giving an immediate reading. The results can then easily be directed back to the players in reference to how much fluid they need to attain optimal hydration.
The test is repeated the following day during the recovery session. The aim of the test is to supply players with information regarding their preparation prior to matches and accelerating recovery following matches. The results are provided to the players in a simple printed table format.
The players are required to recall their preparation and recovery routines in relation to the match and make adjustments to their hydration procedure to ensure they are better hydrated for their next match.
Body Weight Testing before and after a match is a reliable reflection of fluid levels and can also be an indicator of hydration. The loss of body water during a match is reflected in changes in body weight from before to after a match.
Dehydration of greater than two percent loss of body weight increases the risk of nausea, vomiting, diarrhoea, and other gastro-intestinal problems during exercise, which will directly effect performance.
Throughout the season, the protocol for the players is to weigh in with minimal clothing before the match, and then repeat the weigh in with the same amount of clothing following the match.
A percentage loss of pre-match mass is calculated and displayed. If a player has a loss greater than two percent of pre-match mass in the post-match weigh in he was required to increase his fluid intake and repeatedly weigh in and hydrate until he had gained his required weight before leaving the ground.
In addition to fluid loss during a match, carbohydrates (the body’s main energy supply) are also constantly being depleted from the body. To minimise the risk of dehydration and carbohydrate depletion throughout a match, players are encouraged to re-hydrate with carbohydrate/electrolyte formula sport drinks as well as water.
As the carbohydrate stores are being depleted at the muscular cellular level, there is an uptake from the blood of glucose by the muscles. As the blood glucose level falls, the body then produces glucose from the liver to maintain the blood glucose levels. As the body’s supply of glucose becomes depleted, carbohydrate replenishment must occur to maintain glucose levels and performance.