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tions (2). Methods An observational field study was conducted during the 1188 km Race around Slovenia. The nutritional intake was recorded by using a standardized food-log. All of the foods and fluids consumed were weighted and recorded. Each of the 6 athletes had to provide his own race provisions and to rely on a support crew to meet the planned nutritional intake. Anthropometric data are based on self-reports of the subjects. All the food-logs were calculated with DGE-PC software. Results The energy and fluid intake of six male finishers (age 36,5 ± 9,1 years; weight 76,8 ± 8,8 kg; height 181 ± 7,0 cm; BMI 23,3 ± 1,4 kg/m2; 21,6 ± 8,0 average training hours per week; weekly training distance of 595,8 ± 296,0 km; with 6,6 ± 3,4 years of experience in ultra-cycling and no nutrition-related diseases) was 72,52 ± 12,71 MJ and 29,78 ± 7,65 l of fluids in total, respectively. Of the total caloric intake, 72,0 ± 11,9 % derived from carbohydrates, 15,4 ± 11,2% from fat, 13,8 ± 2,9% from protein. The average energy intake in solid form was 14,3 ± 13,2%, the energy intake in form of liquids 85,7 ± 13,2%. Per hour the subjects consumed 1,52 ± 0,27 MJ and drank 0,62 ± 0,12 l of fluids. The CHO intake per hour was 68,4 ± 15,5g. Discussion The recommendations of 90 g of CHO per hour (2) in endurance events lasting 2,5 h or more could not be reached by any competitor, thus a CHO intake plan is crucial even for experienced cyclists.
Wageningen University Introduction Among amateur team-based sports, it is common to drink moderate to large amounts of alcoholic beverages, mainly beer, after training or competition. Alcohol is known to increase urine output, which could interfere with adequate rehydration after exercise.
Only a few studies addressed the effect of alcohol on rehydration after exercise [Shirreffs; Hobson]. Results suggested that the diuretic effect of alcohol is blurred when the body is dehydrated. Beer contains - besides alcohol - water, carbohydrates and a small amount of electrolytes. The final consequences of beer consumption for rehydration and fluid balance are not completely clear. Therefore, we assessed the effect of beer consumption, with a range of alcohol content, on fluid balance after exercise-induced mild dehydration. The rehydration capacity of the beers was compared with isotonic sports drink and water. Methods Ten healthy males were included in this cross-over intervention study (age 24.7±5 yrs, body weight 75.9±3.1 kg, VO2max 57.7±6.4 ml/kg/min). Each subject underwent five experimental conditions: non-alcoholic beer, 2% alc beer, 5% alc beer, an isotonic sports drink and water. They exercised until mild dehydration, i.e. 1% body mass reduction (~ 750 mL). Thereafter, in random order, one of the experimental beverages was consumed, in an amount equal to 100% of their sweat loss. Up till 5 hours after the last consumption urine was collected at regular intervals. Urine output was measured, and fluid balance was calculated. Results Beverage consumption clearly affected urine output. After 1 hour, urine production was significantly higher for 5% beer compared to the isotonic sports drink (308±148 mL vs 101±70 mL; p 0.01). At the end of the 5-hour observation period fluid balance was negative for all conditions, with the poorest balance for 5% beer (-606±178 ml, ~ 19% rehydration) and the best balance for the isotonic sports drink (-452±252 mL, ~ 40% rehydration). Non-alcoholic beer, 2% beer and water respectively resulted in a fluid balance of -495±229 mL (31%), -534±289 mL (32%) and -499±193 mL (33%). Conclusion Beer with an alcohol content of 5% had a negative impact on fluid balance and rehydration after exercise. While low alcoholic beer (2%) and nonalcoholic beer led to a comparable fluid balance as plain water, indicating that the diuretic effect of a low dose of alcohol is limited.
Drinking an isotonic sports drink, however, appeared to be the best option for rehydration. References Shirreffs, S.M. and R.J. Maughan, J Appl Physiol., 1997. 83(4): p. 1152-1158. Hobson, R.M. and R.J. Maughan, Alcohol Alcohol., 2010. 45(4): p. 366-373.
EFFECT OF GREEN TEA EXTRACTS SUPPLEMENTATION ON FATTY ACID OXIDATION AND MOLECULAR MECHANISM
INVOLVED IN GLYCOGEN SYNTHESIS IN EXERCISED HUMAN SKELETAL MUSCLECheng, I.S., Chen, H.W., Lai, H.P., Liu, H.C.
National Taichung University of Education Introduction In Taiwan, green tea has been habitually consumed as one of the most popular beverages. Green tea contains GTEs of polyphenolic flavonoids known as tea catechins (TC), which comprise epigallocatechin gallate (EGCG), epicatechin gallate, and gallocatechin gallate. In human and animal studies, green tea extract (GTE) has been shown to increase the proportion of whole body fat utilization by activating PPARγ and increases CPT1 expression (Dulloo et al., 1999; Venables, Hulston, Cox, & Jeukendrup, 2008). Little study is regarding to whether GTE administration is expected to cause metabolic consequence in turn to result in improvement of glycogen synthesis in exercised human skeletal muscle. The purpose of this study was to demonstrate the effect of green tea extracts supplementation on fatty acid oxidation and molecular mechanism involved in glycogen synthesis in exercised human skeletal muscle. Methods Eight male athletes (aged 22 ± 0.6 years) will be participated in this crossover designed study, and served as placebo and GTE trails (130 mg GTE/day for 8-week). Then, subjects will be crossed-over again with separation of 8 weeks. On the day of the experiment, a single bout of 60-min cycling exercise at 75 % (VO2 max) will be performed and subjects consume a carbohydrate meal (2 g carbohydrate/kg body weight, 80 % carbohydrate, 8 % fat, 12 % protein) immediately after exercise. Biopsied muscle samples will be obtained from vastus lateralis immediately and 3 h after exercise. Simultaneously, blood sampling and gas analysis will be performed before and after exercise. Results The significant glycogen synthesis were shown in GTE trial compared to placebo trial in exercised human skeletal muscle (p.05). Yet, all parameters which included blood glucose, NEFA, glycerol and serum insulin or RER, carbohydrate oxidation rate and fat oxidation rate were no significantly different between GTE and placebo trials. Discussions The results of this study concomitant with the evidences in animal study that GTE enhance the glycogen synthesis after exercise (Murase, Haramizu, Shimotoyodome, Tokimitsu, & Hase, 2006). Therefore, the molecular mechanisms underlying on muscle glycogen synthesis with GTE supplementation will be examined in next four months. The study showed that GTE significantly influenced metabolic consequence, which in turn affects the glycogen re-synthesis in exercised human skeletal muscle. We suggested that GTE could be as ergogenic aid to athletes who are training for competitions. References Dulloo, A. G., Duret, C., Rohrer, D., Girardier, L., Mensi, N., Fathi, M.,... Vandermander, J. (1999). The American journal of clinical nutrition, 70(6), 1040-1045. Murase, T., Haramizu, S., Shimotoyodome, A., Tokimitsu, I., & Hase, T. (2006). American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 290(6), R1550-R1556. Venables, M. C., Hulston, C. J., Cox, H. R., & Jeukendrup, A. E. (2008). The American journal of clinical nutrition, 87(3), 778-784.
EFFECT OF DEHYDRATION ON BASKETBALL SKILL PERFORMANCE IN FEMALE PLAYERSBrandenburg, J.
University of the Fraser Valley Introduction Basketball is characterized by repeated bouts of high-intensity effort and requires the execution of complex sport-specific motor skills. Thus, players are at risk for developing dehydration and experiencing dehydration-related decrements in skill performance.
In experienced male players, dehydration reduced basketball skill performance (Baker et al.). Whether skilled female players are similarly affected by dehydration is unknown. Thus, the purpose was to examine the effect of dehydration, induced by simulated game play, on shooting accuracy, agility, and perception of effort (RPE) in female basketball players. Methods Participants were 10 female basketball players (174.4 ± 7 cm; 21 ± 1 y; 78.3 ± 13 kg) from a nationally ranked university team. Participants completed a 40-min simulated game on 2 different days. During one game, players ingested water at a rate to match fluid losses (EUH) where as no fluid intake was permitted during the other game (DEH), with the order randomized. Prior to each game, urine samples were collected to ensure players started adequately hydrated. To determine the degree of dehydration (% loss in body mass), body mass was assessed before and immediately after each game. Body mass was also monitored regularly during EUH to ensure fluid ingestion matched fluid losses. Throughout both games RPE were monitored. Shooting performance (2- and 3-point jump shots) and agility (using the T-test) were assessed following each game. Paired sample t-tests were performed to examine if differences between EUH and DEH were significant and effect sizes (ES, Cohen’s d) were calculated to determine the magnitude of the differences. Results Pregame urine specific gravity for EUH equaled 1.009 ±
0.007 and was 1.008 ± 0.007 for DEH. The degree of dehydration was significantly greater in DEH (1.3 ± 0.3%) than in EUH (0 ± 0%).
Players made 68.8 ± 9% and 63.8 ± 12% of 2pt shots in EUH and DEH, respectively (p=0.07, ES = 0.46). In EUH, players made 49.2 ± 13% of 3pt shots while 47 ± 14% were made in DEH (p=0.45, ES = 0.16). There were no differences in the time to complete the T-test (EUH= 10.3 ± 0.5 s; DEH= 10.2 ± 0.6 s). RPE was significantly higher during DEH (15.2 ± 1.2) than in EUH (14.6 ± 1.3) (p=0.02, ES = 0.5). Discussion The modest degree of dehydration experienced by female players during simulated game conditions did not affect 3pt shooting accuracy as well as agility. Regarding 2pt shooting performance, the moderate effect size and a EUH vs. DEH difference (5%) that approached significance suggest 2pt shooting accuracy experiences a meaningful decrement as a result of dehydration. Dehydration also increased the perception of effort, and practically, these greater feelings of fatigue may translate into a drop in playing intensity. Baker et al. 2007. Med Sci Sports Exerc, 39, 1114–23.
BEER AS A SPORTS DRINK? MANIPULATING BEER’S INGREDIENTS TO REPLACE LOST FLUID.Desbrow, B., Murray, D., Leveritt, M.
Purpose: To investigate the effect of manipulating the alcohol and sodium content of beer on fluid restoration following exercise. Method:
Seven male volunteers exercised on a cycle ergometer until 1.96±0.25% body mass (mean±SD) was lost. Participants where then randomly allocated a different beer to consume on four separate occasions. Drinks included a low alcohol beer (2.3% ABV) [LightBeer], a low alcohol beer with 25 mmol.L-1 of added sodium [LightBeer+25], a full strength beer (4.8% ABV) [Beer] or a full strength beer with 25
mmol.L-1 of added sodium [Beer+25]. Volumes consumed were equivalent to 150% of body mass loss during exercise and were consumed over a 1h period. Body mass and urine samples were obtained before and hourly for 4h after beverage consumption. Results:
Significantly enhanced net fluid balance was achieved following the LightBeer+25 trial (-1.02±0.35 kg) compared to the Beer (-1.59±0.32 kg) and Beer+25 (-1.64±0.28 kg) treatments. Accumulated urine output was significantly lower in the LightBeer+25 trial (1477±485 mL) compared to the Beer+25 (2101±482 mL) and Beer (2175±372 mL) trials. Conclusion: A low alcohol beer with added sodium offers a potential compromise between a beverage with high social acceptance and one which avoids the exacerbated fluid losses observed when consuming full strength beer.