As a football (soccer for our friends across the pond) enthusiast I have decided to provide you with a brief (due to my impending exams) nutritional strategy, to maximize both performance during a game and recovery after a game. These guidelines apply for all intermittent team sports (e.g. rugby)!
1) Pre-match strategy:
It is important for players to ensure they maximize glycogen (storage form of carbohydrate) stores prior to a game. The development of fatigue during a game appears to be related to depletion of muscle glycogen stores. Krustrup et al (2006) found that whole muscle glycogen decreased by 43% during a football match and that almost half of the muscle fibres were completely, or almost empty of glycogen after the game. Depleted carbohydrate stores have been found to negatively effect psychological confidence. This is because glucose is the brains only fuel source. When carbohydrate stores are low, the brain will send a signal to the muscles to ‘spare’ glycogen, resulting in termination of exercise (not quite as simple as that but you get the point).
In order to maximize glycogen stores it is recommended to consume a low GI rich carbohydrate meal about 3 hours before exercise. It is genuinely considered detrimental to consume carbohydrate less than an hour before a match (however evidence is not conclusive). Sherman et al demonstrated that ingestion of 312 grams of carbohydrate 4 hours prior to strenuous exercise resulted in a 15% improvement in exercise performance, whereas no improvement was observed in the group that consumed carbohydrate 45 minutes prior to exercise. Consuming a low GI meal is also important. GI, aka glycemic index is a measure of the effect of carbohydrate on blood insulin levels. A high GI food results in a quicker and more pronounced insulin response than a low GI food. Recent findings have shown significant improvements in both running time-to-exhuastion and time trial following ingestion of low GI foods, compared to high GI foods consumed 3 hours before exercise. An example of a good pre match nutrition strategy would be to consume 1-4 g/kg during the 6 hour period before exercise, no later than 3 hours prior to exercise. An example of a good pre-match meal would be a large serving of porridge, with milk and a banana (No later than 3 hours before the game).
2) During the match:
Intermittent sports, lasting over an hour, such as football are thought to benefit from carbohydrate ingestion during a match. Ali.A et al concluded that ingestion of a carbohydrate-electrolyte solution during exercise enabled subjects with compromised glycogen stores to better maintain skill and sprint performance when ingesting fluids alone. Therefore, sports drinks such as Lucozade have been found to improve performance. Get yourself a supply of sports drinks, or alternatively make your own. Some sugar free orange squash with a couple of pinches of salt should do the trick! Aswell, as ensuring adequate supply of carbs during the match, a sports drink will also help replace fluid and electrolyte losses.
Mechanisms by which supplementary carbohydrate during exercise enhances performance:
- provision of an additional muscle fuel source, when glycogen stores become depleted
- glycogen sparing
- prevention of low blood glucose concentrations
- effect on the central nervous system (brain and spinal cord)
3) Post match strategy
Post match strategy is all about replenishing your glycogen stores! When periods between training are <8 hours carbohydrate should be ingested as soon as practically possible. Immediately after exercise is a crucial time to replenish glycogen stores. Moderate and high carbohydrate GI foods provide a readily availiable source of carbohdrate for glycogen synthesis. Another tip is to choose nutrient rich snacks to aid recovery. The optimal carbohydrate quantity is about 1-1.5 g/min after exercise. Examples of mod-high G.I. foods include honey, pasta and most rice. Nutrient rich snacks include flavoured youghurt, smoothies, etc.
Supplements for consideration:
Protein
Creatine
Caffeine
Nitrate
Buffers
Concluding statement:
Prior to a match a low G.I carbohydrate rich meal should be consumed no later than 3 hours before. Carbohydrate ingestion, via sports drinks during a game has been shown to improve performance. Glycogen resynthesise should start as soon as possible with consumption of a moderate-high GI meal.
Full time!
Thanks for reading!
This may be the last blog for a good couple of weeks, due to the joys of final year exams! Keep upto date with Science2Sport by following on twitter (click the icon at the top).
Joe