Effect of carbohydrate and carbohydrate-protein supplementation on power performance in collegiate football players performing a simulated game task

Abstract

Research has shown conflicting results involving the efficacy of carbohydrateprotein beverages on athletic performance. Purpose: To examine whether or not power output during the latter stages in a series of repeated maximal or near maximal effort anaerobic exercise bouts simulating a football game task was altered when consuming a carbohydrate-protein (CP) beverage versus either a carbohydrate-only (C) beverage or a placebo (P). Methods: Eighteen collegiate male football players participated in this investigation. The subjects' mean age, height, weight, and percent body fat were 20yr, 180.4cm, 92.4kg, and 12%, respectively. The experimental exercise sessions were completed by each athlete on three separate occasions, spaced one week apart. Subjects were asked to perform a series of maximal-effort weighted sled-pushes, which simulated a game-type activity over two halves of a football game separated by a 20-minute simulated halftime recovery period. Maximal muscle power was assessed through the use of a series of maximal jump-and-reach tests. The experimental beverages were administered during the first 5 minutes of halftime. Water was permitted ad libitum throughout each exercise session. The experimental beverages used included; 1) a commercially available flavored aspartame-sweetened P beverage, Crystal Light, (300 ml,5 kcal), 2) a commercially available C beverage, Gatorade Energy Drink®, (300 ml, 67.5 g CHO, 270 kcal), and 3) a commercially available CP beverage, Gatorade Nutrition Shake®, (243 ml diluted with water to 300 ml, 45 g CHO, 15 g Protein, 270 kcal). All beverages were randomly assigned and each player received all three beverages. An analysis of covariance (ANCOVA) was used to determine if differences existed in power output between the experimental beverages. Results: The Least Square Mean (LSM) for jump-power was significantly higher after C compared to CP (1587.36 watts vs. 1577.42 watts, respectively; p=0.0095). The LSM jump-power after the P beverage was also lower than after the C beverage (1582.52), but was not statistically significant. Conclusions: These data suggest that average power output over a series of high-intensity anaerobic exercise bouts, which simulate football game tasks, is greatest after consuming a C beverage during the halftime break compared with consuming a CP or P beverage.