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Factors influencing nutritional supplement use by high school students were assessed. Comparisons were made between various groups of sports participants and non-sports participants. The Nutritional Supplement Use and Knowledge Scale was administered to 509 students. Mean supplement use score was 10.87 (SEM = 0.50, range 0-57). Mean knowledge score was 13.56 (SEM = 0.16, range 1-21). Significant relationships (p < .01) were obtained for supplement knowledge with use, and supplement use with gender. ANOVA found significant differences between supplement use by gender (p < .01), supplement use by sports category (p < .05), and knowledge scores by sports category (p < .01). Discriminant function analysis indicated knowledge, supplement use, and subscores for protein, vitamins/minerals, knowledge, supplement use, and subscores for protein, vitamins/minerals, and carbohydrates were best discriminators of sport group membership. Greater knowledge about supplements was associated with less use; hence, education about supplements can be a deterrent to use. This study may help coaches, athletic trainers, athletic directors, teachers, physicians, and parents identify nutritional misconceptions held by adolescents.

The purpose of this study was to evaluate the adequacy of dietary intake in 16 female heavyweight rowers during the sprint racing phase of the season. Caloric intake for the rowers was 2,633 kcal/day, lower than expected given the training regimen of these athletes. On average, rowers consumed below-optimal levels of carbohydrate. Protein intake was satisfactory but fat intake was higher than recommended. For the majority of rowers, micronutrient intake met the RDA. However, calcium, zinc, B6, and B12 fell short of meeting two-thirds of the RDA for a significant percentage of rowers. The preevent meal consumed both 15 hr and 2 hr before the event provided less carbohydrate and fluid but more fat than desirable. Female heavyweight rowers would benefit from nutritional counseling that provides strategies for increasing complex carbohydrates, calcium, zinc, B6, and B12 while reducing dietary fat. Adequate fluid intake is also essential.

This investigation examined the plasma glucose and insulin response in 6 trained athletes after consumption of four commercially available sport feedings 2 hr before as well as immediately after 1 hr of running under common training conditions. Four feedings were compared: Feeding 1, 160 g CHO/400 ml; Feeding 2, 69 g CHO/400 ml; Feeding 3, 69 g CHO + 6 g protein/400 ml; and Feeding 4, solid 69 g CHO + 5 g protein + 4 g fat. Before the training session, there were no differences between the four sport feedings in the area under the glucose and insulin curves and the insulin/glucose ratio. However, after exercise, Feeding 2 resulted in a significantly greater area under the glucose curve compared with Feedings 1, 3, and 4 (respectively, 352 vs. 241, 251, and 182) and a significantly lower insulin/glucose ratio compared with Feeding 1 (respectively, 6.2 vs. 15.8). Therefore, it is concluded that the kind of sport feeding may influence postexercise glucose and insulin responses.

Reduction of body stores of carbohydrate and blood glucose is related to the perception of fatigue and the inability to maintain high-quality performance. This has been clearly shown with aerobic, endurance events of moderate intensity of over 90 min duration. Carbohydrate intake may also have relevance for athletes involved in short, high-intensity events, especially if body weight control is an issue. Prevention of carbohydrate depletion begins with a high-carbohydrate training diet of about 60-70% carbohydrate. If possible, carbohydrate beverages should be consumed during the event at the rate of 30-70 g/hr to reduce the chance of body carbohydrate depletion. Finally, replacement of body carbohydrate stores can be achieved most rapidly if 40-60 g of carbohydrate is consumed as soon as possible after the exercise and at repeating 1-hr intervals for at least 5 hr after the event.

Caffeine ingestion (3-9 mg/kg body weight) prior to exercise increases performance during prolonged endurance exercise and short-term intense exercise lasting approximately 5 min in the laboratory. These results are generally reported in well-trained elite or recreational subjects. However, there is a lack of well-controlled field studies to determine the applicability of laboratory results to the athletic world. Caffeine does not appear to enhance performance during incremental exercise tests lasting 8-20 min and during sprinting lasting less than 90 s, although research examining sprinting is rare. In addition, the mechanisms responsible for any improvement in endurance and short-term exercise have not been clearly established. The ergogenic effects of caffeine are present with urinary caffeine levels that are below the limit of 12 micrograms/ml allowed by the International Olympic Committee, which raises serious ethical issues regarding the use of caffeine to improve athletic performance. One solution would be to add caffeine to the list of banned substances, thereby requiring athletes to abstain from caffeine ingestion 48-72 hr prior to competition.