This double-blind experiment examined the effects of a caffeinated sports drink during prolonged cycling in a warm environment. Sixteen highly trained cyclists completed 3 trials: placebo, carbohydrate-electrolyte sports drink (CES), and caffeinated sports drink (CES+CAF). Subjects cycled for 135 min, alternating between 60% and 75% VO2max every 15 min for the first 120 min, followed by a 15-min performance ride. Maximal voluntary (MVC) and electrically evoked contractile properties of the knee extensors were measured before and after cycling. Work completed during the performance ride was 15-23% greater for CES+CAF than for the other beverages. Ratings of perceived exertion were lower with CES+CAF than with placebo and CES. After cycling, the MVC strength loss was two-thirds less for CES+CAF than for the other beverages (5% vs. 15%). Data from the interpolated-twitch technique indicated that attenuated strength loss with CES+CAF was explained by reduced intrinsic muscle fatigue.
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"Contrary to what was found in the present study, others (Geiß et al., 1994) have tested the effects of EDs on 10 male endurance athletes and reported longer cycling times to exhaustion after cycling for 60-min at 70% VO 2max on a cycle ergometer under the ED condition compared to two placebo beverages partially lacking the full-set of ingredients of an ED. Other endurance cycling experiments with cyclists have been conducted (Cureton et al., 2007; Ganio et al., 2010; Ivy et al., 2009) with similar results showing more accumulated work with ED. Nonetheless, another endurance study with male runners (Umaña-Alvarado & Moncada-Jiménez, 2005) found no significant differences in mean running times between ED and placebo conditions. "
[Show abstract][Hide abstract] ABSTRACT: To determine the acute effect of an energy drink (ED) on physical performance of professional female volleyball players. 19 females (age= 22.3±4.9 yr.; height= 171.8±9.4 cm; weight= 65.2±10.1 kg) participated in a randomized, crossover, double-blind study to measure grip strength, vertical jump and anaerobic power in 3 different sessions (ED, placebo [PL] or no beverage [CTL]). For each session, participants arrived in a fasted state, consumed a standardized breakfast meal, and 1 h later completed the 3 baseline performance tests without having ingested the beverage. After completing the pre measurements, the athletes drank 6 ml/kg of body weight of the ED or PL and in the CTL condition no beverage was consumed. Post-test measurements were taken 30 min after the ingestion of liquids. A 3x2 repeated measures ANOVA revealed no significant within session and measurement time interactions for each performance test. Regardless of the measurement time, right hand grip strength was significantly higher in the ED condition (34.6±0.9 kg) compared to PL (33.4±1.1 kg) and CTL (33.6±1.0 kg) (p < 0.05). Regardless of the beverage ingested, averaged right hand grip strength, taking into account all 3 testing conditions, increased from pre to post-testing (Pre = 33.8±0.9 kg vs. Post = 33.9±1.0 kg; p = 0.029), as did the averaged fatigue index, obtained from the anaerobic power test (Pre = 65.9±2.2% vs. Post = 68.7± 2.0%; p= 0.049). The acute ingestion of an ED did not improve physical performance of professional Costa Rican female volleyball players.
International journal of sport nutrition and exercise metabolism 11/2014; DOI:10.1123/ijsnem.2014-0101 · 2.44 Impact Factor
"Several studies have shown that an intake of 3 to 6 mg caffeine per kg bodymass or 450 mg improves performance of athletes especially in endurance exercise     without risking dehydration or imbalance of the electrolyte household  . "
[Show abstract][Hide abstract] ABSTRACT: Background: In contrast to caffeine bars, the effect of caffeine intake from tablets and energy drinks on endurance performance has already been investigated. Therefore, the aim of the study is to examine the effects of caffeine bars used as pre-exercise supplements on endurance performance in cycling. Methods: The present study was designed as a randomized single-blind cross-over placebo-controlled trial. Nine male, trained cyclists completed endurance exercises on a cycling ergometer under the following conditions: ingestion of water (WAT), placebo bars (PLA) and caffeine bars (CAF; 5 mg caffeine/kg bodyweight), respectively, 45 min prior to the test. After 40 min at a constant intensity of 75% VO 2 max (assessed in a previously performed incremental test) load was increased 10 W/min until exhaustion. Results: CAF compared to PLA resulted in a higher maximal power and longer time to exhaustion (p = .002). Surprisingly, concentration of free fatty acids was lower at exhaustion (p = .004), whereas blood lactate levels (p = .021) and heart rate (p = .008) were significantly higher after CAF. Subjects also reported lower received perception of effort at warm-up (0.034), 30 min (p = .026) and 40 min (p = .041) only after CAF. Conclusions: Caffeine bars are useful pre-exercise supplements. Their performance enhancing effect was rather due to a delayed perception of fatigue than an increased lipolysis, proving caffeine as central nervous system stimulant.
"Based on a possible mechanism exercise performance would be supposedly improved by quercetin through reducing damage to skeletal muscle and contractile proteins, so quercetin could reduce muscle damage, tenderness, fatiguing, and negative effects of increased reactive oxygen production following exercise; however, the evidences are contradictive. Another theory explained that quercetin practically the same as caffeine, by reducing the sensitivity of pain, may influence exercise performance. Additionally, positive effects of quercetin on skeletal muscles may partially elucidated via increases in mitochondrial protein, stimulating mitochondrial biogenesis and increasing oxidative enzyme activity.[29–31] "
[Show abstract][Hide abstract] ABSTRACT: Quercetin is a health-enhancing antioxidant bioflavonoid (1-3). This flavonoid occurs in variety of natural fruits and vegetables such as apple, cranberry, onion, broccoli, and teas. Many studies have shown that quercetin has possible positive effects on exercise performance. The aim of this study is the evaluation of effects of quercetin supplementation on VO2max and exercise performance in female athletes.
This study was done on 26 young female swimmers. Participants were assigned in to groups and supplemented orally for 8 weeks with either Quercetin (Solaray(®), USA, Inc) or placebo (dextrose). Before and after intervention, athletes performed a continuous graded exercise test (GXT) on an electronically braked cycle ergometer (Lode, The Netherlands) to determine VO2max and time to exhaustion (TTE).
Participants in the quercetin group consumed higher energy and protein and lower carbohydrates and fats. There was no significant differences in VO2max, TTE, lactate, and body fat between pre- and post-supplementation neither in the placebo group nor in the quercetin group.
It is concluded that quercetin supplementation (1000 g/day) for 8 weeks in female athletes didn't show any significant association with exercise performance.
International journal of preventive medicine 04/2013; 4(Suppl 1):S43-S47.