Ernährung & Sport

Abstract

The study examined the influence of the isotonic beverage (SP) which combines several potentially ergogenic substances and pre-exercise diet on endurance performance.In a randomized cross-over-design, nine male sport students (252,5yr; VO2max: 527.4 [mlmin-1kg-1]) ingested500ml of SP or a placebo each time 24h and 1h prior to the test. 500ml SP contained among other ergogenics 31.4g CHO (0.420.04g per kg body mass; 120kcal) and 150mg caffeine (2.010.2mg per kg bodyweight) respectively. To control dietary effects,food intake was additionally documented from a 24h period before the test.During exercise testing (100 wattsstart workload; 50 wattsincrease every 3 minutes to subjective exhaustion) heart rate, ventilation, oxygen uptake and carbon dioxide output as well as blood lactate were measured.Compared to placebo, the maximum and submaximum values for endurance performance were significantly improved with SP. Maximum heart rate (1836.7 vs. 1876.4bpm; p<0.05) and maximum power output (29226.9 vs. 29927.9 watts; p<0.05) increased by 2%on average. Simultaneously,maximum blood lactate(10.92.1 vs. 13.42.3mmol/L; p<0.05) was significantly elevated by 18% on average. Power output at the individual threshold (Dmax) increased by 3% (22021.3 vs. 22623.7 watts; p<0.05).These improvements could be primarily explained through the combined ingestion of caffeine, carbohydrates (glucose/fructose) and/or bicarbonate and zinc. Arguable are intraindividual effects of the combined contents of the beverage.KEY WORDS: Endurance Performance, Incremental Test, Sports Nutrition, Beverages, Ergogenics, Coffeine, Carbohydrates, Energy Metabolism