Lee, C-L., Cheng, C-F., Astorino, T. A., Lee, C-J., Huang, H-W., & Kuo, Y-H.(2012). Effects of carbohydrate-caffeine supplementation on repeated high-intensity performance in elite female athletes. Presentation 2787 at the 59th Annual Meeting of the American College of Sports Medicine, San Francisco, California; May 29-June 2, 2012.

This study evaluated the effects of carbohydrate and caffeine supplementation on metabolism and repeated high-intensity sprint exercise performance in female athletes (N = 11). Ss completed four trials all separated by seven days. Treatments were caffeine, caffeine + carbohydrate, carbohydrate, and a placebo. Ss consumed 6 mg/kg BM of caffeine or placebo one hour before repeated high-intensity sprint exercise and 0.8 g·kg-1 BM of a carbohydrate drink (glucose) or placebo immediately before the start of a test on a cycle ergometer. Repeated high-intensity sprint exercise consisted of 10 sets of 5 × 4-second bouts of maximal sprint exercise with 20 seconds of active recovery between bouts. Blood samples were obtained to assess changes in lactate, blood glucose, testosterone, and cortisol across time and treatment.

During the first set of repeated high-intensity sprint exercise, peak power and mean power were significantly higher in the caffeine + carbohydrate trial than in the carbohydrate and placebo trials. No significant differences were shown between caffeine + carbohydrate and caffeine treatments. During sets 6 and 7, peak power and mean power were significantly increased by 6.0 % with caffeine + carbohydrate versus caffeine, but there was no significant difference in performance between caffeine + carbohydrate and carbohydrate. No significant differences in performance were observed across treatments during sets 2-5 and 8-10. Compared to placebo, blood lactate and glucose were significantly increased under the caffeine + carbohydrate, carbohydrate, and caffeine treatments. No significant differences in testosterone or cortisol were found.

Implication. In female athletes, a combination of caffeine + carbohydrate improved repeated high-intensity sprint exercise performance versus carbohydrate alone during the early phases of sprint exercise. Performance during the latter phases may be further enhanced compared to caffeine alone.

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