This summary is from the IAAF 2nd International Consensus Conference on “Nutrition for Athletics“ held in Monaco from April 18-20, 2007. Copies of the CD and booklet are available from the IAAF website www.iaaf.org.
Nutrition for Sprints
Presenter: Kevin Tipton (GBR)
Although nutrition for the sprint events has not received as much attention as it does in distance running, it can have a profound effect on recovery from training and competition, training adaptations and power to weight ratio. General recommendations for all sprinters are, at best, useless. Very specific guidelines cannot and should not be given for macronutrient intakes Individual needs should be considered and only ranges should be given.
Recommendations for use of specific foods to ward off drowsiness or improve reaction time cannot be given at this time because of a lack of data to either support or discount the effects.
Race day foods and drinks should be individually tested so that the chance of GI (gastro-intestinal) discomfort is minimized. Careful consideration of what not to eat is probably more important than what to eat.
Although weight training is an important component of a sprinter’s programme, it should be noted that optimal mass does not equal a maximal mass. Changes is muscle mass will be induced by training plus nutrition. Protein balance does not become positive without provision of exogenous amino acid sources. This can be obtained from foods as well as from special products. A relatively small amount of exogenous amino acids, probably 10-15g of a mixed protein, results in a positive protein balance. Leucine does not seem to have an effect when enough carbohydrate and protein provided. Energy balance is just as important, if not more so, for muscle hypertrophy as protein intake. Weight training should never be done in a glycogen depleted state, since there is evidence that this will reduce the maximal anabolic response.
Total protein needs are dependent on the timing of ingestion, type of protein, other nutrients ingested and training stimuli. It has been shown that athletes have a need for more than 1.7g/kg/day, although it should be noted that this requirement is measured in the most extreme activities, like Tour de France cycling. Most athletes do not need this amount and many consume this amount in their habitual diet without the need to supplement. Supplements might be useful for convenience or accuracy of ingested amounts. Because of adaptive responses, a higher protein intake results in greater protein oxidation. If protein intake is reduced suddenly, the oxidation rate remains high for some time and the athlete risks short-term negative protein balance.
The side effects of high protein intake have been largely overestimated. Risks reported in the literature include kidney damage and bone demineralization. Kidney damage has never been shown in otherwise healthy individuals. Bone contains a large amount of protein and, in fact, bone collagen responds similarly to muscle proteins following ingestion of a protein source. However, there is no rationale for advocating protein intakes above 1.7g/kg/day. Furthermore, high protein intake might compromise carbohydrate intake, which should be sufficient to maintain glycogen stores during periods of training and racing (~ 5g/kg/day, but dependent on the amount and intensity of training). There was discussion about post-exercise protein breakdown. It was hypothesised that protein breakdown might not be a bad thing as it might have a role in muscle remodeling. Clearly, more research is needed.
Creatine can enhance power and increase muscle mass, however the extra weight gain can negatively impact performance. The most important effect of creatine seems to be that more work can be done during high intensity training programmes. Data remain equivocal, but, importantly, none of the available studies has reported impaired performance. Furthermore, some data indicate increased glycogen storage when carbohydrate is co-ingested with creatine.
Buffering agents such as bicarbonate and alanine are not recommended at this time for sprint events. Despite wide use in elite 400m runners, effects have rarely been shown under one minute of exercise. There is a rationale with regard to increased training outputs, but adaptive responses might be compromised.
The above summary was written by Peter Res
If you wish to download this handy Grams and Calorie Calculator for Carbohydrate, Protein, and Fat, click here for the Excel spreadsheet.
This is part 2 of 14 in a series from the 2007 2nd IAAF International Consensus Conference “Nutrition for Athletics”