Wednesday, March 11, 2009

Cutting-Edge Research: Chocolate Milk for Tournaments?

After an intense match, muscle glycogen and blood glucose levels may be very low. That is, athletes may be very low on energy. The only way to refuel the system, so to speak, is through the diet or post-game meal. During a tournament, when two matches are played on the same day, players need to have a nutritional strategy to prepare themselves for the second match of the day - what to eat and drink between matches. In a study just released by the journal Applied Physiology, Nutrition and Metabolism, investigators from Northumbria University found that chocolate milk might be an ideal recovery drink.

The study examined the effects of three drinks on recovery and performance, chocolate milk (2%), Gatorade and Endurox. The subjects first exercised on a stationary bicycle for ~65 minutes, alternating 2 min intervals of pedaling at 75% and 50% of their max. This bout of exercise was designed to deplete the muscles of glycogen. They were allowed to recovery for four hours after which they rode at 70% of their max for as long as possible. During the recovery they drank one of the three beverages. Part was consumed immediately after exercise and the rest 2 hours later (~500ml or 1 pint total).

The investigators found that when the subjects drink chocolate milk during the 4 hour recovery period, they able to exercise longer considerably during the endurance trial (32 min versus 23 and 21 min). The difference was remarkable with chocolate milk resulting in increased endurance of 43-51%.

Compared to most sports drinks, 2% chocolate milk has slightly more carbohydrate and much more fat and protein. The benefit of chocolate milk may lie in these latter ingredients. Studies have shown that consuming a small amount of protein with carbohydrate during recovery enhances the muscles replenishment of glycogen. Also, a small amount of fat can raise blood levels of free fatty acids which can be used as energy during prolonged exercise.

There are a few problems with the study that might account for a portion of the difference in performance between the endurance trials. Also, the amount of beverage consumed, ~16 oz over a four hour period is probably less than the typical athlete might drink between matches. However, despite those concerns, the study has important implications for soccer, especially at tournament time. The initial exercise bout and the recovery time are similar to what takes place at many tournaments. Despite some of the soccer governing bodies wanting to limit teams to one match per day, most tournaments still require teams to play two matches per day. Usually these matches are separated by 3-4 hours. Thus, the time course of the study simulates tournament conditions, Also, the initial bout of exercise with alternating periods of high and moderate intensity exercise is similar to what is performed during a match.

On balance this study agrees with an earlier post on the Science of Soccer Online. Milk, particularly chocolate milk, seems to be a very effective recovery drink.

Reference:

Thomas K, Morris P, Stevenson E (2009) Improved endurance capacity following chocolate milk consumption compared with 2 commercially available sports drinks. Applied Physiology Nutrition and Metabolism, 34: 78-82.