No Effects of Three-week Consumption of a Green Tea Extract on Time Trial Performance in Endurance-trained Men

2010 ◽  
Vol 80 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Philipp Eichenberger ◽  
Samuel Mettler ◽  
Myrtha Arnold ◽  
Paolo C. Colombani
Keyword(s):  
Energy Metabolism ◽  
Green Tea ◽  
Time Trial ◽  
Green Tea Extract ◽  
Measured Parameter ◽  
Double Blind ◽  
Maximal Power Output ◽  
Time Trial Performance ◽  
Tea Extract ◽  
Trial Performance

The purpose of this study was to examine the effects of three-week consumption of green tea extract (GTE) supplementation on time trial performance and metabolism during cycling in endurance athletes. Nine endurance-trained men participated in this double-blind and placebo-controlled cross-over study. At the end of the supplementation period with GTE (159 mg/day total catechins) or placebo, respectively, subjects cycled at 50 % of the individual maximal power output for 2 hours, followed by a 30-minute time trial. Respiratory gas exchange, fatty acids, 3-β-hydroxybutyrate, lactate, glucose, interleukin-6, thiobarbituric acid reactive substances, creatine kinase, and C-reactive protein (CRP) were measured 1 hour before, during, and 1 hour after the exercise test. Blood lipids were measured at rest before cycling. There was no significant effect on performance, energy metabolism, or any other measured parameter, except for CRP, which was significantly reduced (p = 0.045) after GTE supplementation compared to placebo. GTE supplementation did not affect time trial performance and energy metabolism in endurance-trained men in the non-fasting state. Further studies with athletes, particularly in the fed state, but with higher GTE doses, are needed to address the question whether green tea may influence energy metabolism and performance in athletes.

Carbohydrate and Protein Co-Ingestion Postexercise Does Not Improve Next-Day Performance in Trained Cyclists

2021 ◽  
pp. 1-9
Author(s):  
Hilkka Kontro ◽  
Marta Kozior ◽  
Gráinne Whelehan ◽  
Miryam Amigo-Benavent ◽  
Catherine Norton ◽  
...  
Keyword(s):  
Whey Protein ◽  
Protein Hydrolysate ◽  
Insulin Response ◽  
Time Trial ◽  
Exercise Bout ◽  
Whey Protein Concentrate ◽  
Glucose Disposal ◽  
Double Blind ◽  
Time Trial Performance ◽  
Trial Performance

Supplementing postexercise carbohydrate (CHO) intake with protein has been suggested to enhance recovery from endurance exercise. The aim of this study was to investigate whether adding protein to the recovery drink can improve 24-hr recovery when CHO intake is suboptimal. In a double-blind crossover design, 12 trained men performed three 2-day trials consisting of constant-load exercise to reduce glycogen on Day 1, followed by ingestion of a CHO drink (1.2 g·kg−1·2 hr−1) either without or with added whey protein concentrate (CHO + PRO) or whey protein hydrolysate (CHO + PROH) (0.3 g·kg−1·2 hr−1). Arterialized blood glucose and insulin responses were analyzed for 2 hr postingestion. Time-trial performance was measured the next day after another bout of glycogen-reducing exercise. The 30-min time-trial performance did not differ between the three trials (M ± SD, 401 ± 75, 411 ± 80, 404 ± 58 kJ in CHO, CHO + PRO, and CHO + PROH, respectively, p = .83). No significant differences were found in glucose disposal (area under the curve [AUC]) between the postexercise conditions (364 ± 107, 341 ± 76, and 330 ± 147, mmol·L−1·2 hr−1, respectively). Insulin AUC was lower in CHO (18.1 ± 7.7 nmol·L−1·2 hr−1) compared with CHO + PRO and CHO + PROH (24.6 ± 12.4 vs. 24.5 ± 10.6, p = .036 and .015). No difference in insulin AUC was found between CHO + PRO and CHO + PROH. Despite a higher acute insulin response, adding protein to a CHO-based recovery drink after a prolonged, high-intensity exercise bout did not change next-day exercise capacity when overall 24-hr macronutrient and caloric intake was controlled.

Green tea extract outperforms metformin in lipid profile and glycaemic control in overweight women: A double-blind, placebo-controlled, randomized trial

2017 ◽  
Vol 22 ◽  
pp. 1-6 ◽  
Author(s):  
Monallisa Alves Ferreira ◽  
Anna Paula Oliveira Gomes ◽  
Ana Paula Guimarães de Moraes ◽  
Maria Luiza Ferreira Stringhini ◽  
João Felipe Mota ◽  
...  
Keyword(s):  
Glycaemic Control ◽  
Randomized Trial ◽  
Lipid Profile ◽  
Green Tea ◽  
Green Tea Extract ◽  
Double Blind ◽  
Double Blind Placebo ◽  
Overweight Women ◽  
Tea Extract

Cycling Time Trial Performance 4 Hours After Glycogen-Lowering Exercise Is Similarly Enhanced by Recovery Nondairy Chocolate Beverages Versus Chocolate Milk

2016 ◽  
Vol 26 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Adam U. Upshaw ◽  
Tiffany S. Wong ◽  
Arash Bandegan ◽  
Peter W.R. Lemon
Keyword(s):  
Repeated Measures ◽  
Time Trial ◽  
Chocolate Milk ◽  
Double Blind ◽  
Time Trial Performance ◽  
Cycling Time Trial ◽  
Repeated Measures Design ◽  
Dairy Milk ◽  
Cycling Time ◽  
Trial Performance

Postexercise chocolate milk ingestion has been shown to enhance both glycogen resynthesis and subsequent exercise performance. To assess whether nondairy chocolate beverage ingestion post–glycogen-lowering exercise can enhance 20-km cycling time trial performance 4 hr later, eight healthy trained male cyclists (21.8 ± 2.3y, VO2max = 61.2 ± 1.4 ml·kg-1·min-1; M ± SD) completed a series of intense cycling intervals designed to lower muscle glycogen (Jentjens & Jeukendrup, 2003) followed by 4 hr of recovery and a subsequent 20-km cycling time trial. During the first 2 hr of recovery, participants ingested chocolate dairy milk (DAIRYCHOC), chocolate soy beverage (SOYCHOC), chocolate hemp beverage (HEMPCHOC), low-fat dairy milk (MILK), or a low-energy artificially sweetened, flavored beverage (PLACEBO) at 30-min intervals in a double-blind, counterbalanced repeated-measures design. All drinks, except the PLACEBO (247 kJ) were isoenergetic (2,107 kJ), and all chocolate-flavored drinks provided 1-g CHO·kg body mass-1·h-1. Fluid intake across treatments was equalized (2,262 ± 148 ml) by ingesting appropriate quantities of water based on drink intake. The CHO:PRO ratio was 4:1, 1.5:1, 4:1, and 6:1 for DAIRYCHOC, MILK, SOYCHOC, and HEMPCHOC, respectively. One-way analysis of variance with repeated measures showed time trial performance (DAIRYCHOC = 34.58 ± 2.5 min, SOYCHOC = 34.83 ± 2.2 min, HEMPCHOC = 34.88 ± 1.1 min, MILK = 34.47 ± 1.7 min) was enhanced similarly vs PLACEBO (37.85 ± 2.1) for all treatments (p = .019) These data suggest that postexercise macronutrient and total energy intake are more important for same-day 20-km cycling time trial performance after glycogen-lowering exercise than protein type or protein-to-carbohydrate ratio.

Nitrate Supplementation’s Improvement of 10-km Time-Trial Performance in Trained Cyclists

2012 ◽  
Vol 22 (1) ◽  
pp. 64-71 ◽  
Author(s):  
Naomi M. Cermak ◽  
Martin J. Gibala ◽  
Luc J.C. van Loon
Keyword(s):  
Repeated Measures ◽  
Time Trial ◽  
Submaximal Exercise ◽  
Beetroot Juice ◽  
Limited Data ◽  
Double Blind ◽  
Time Trial Performance ◽  
Ergogenic Effects ◽  
Nitrate Supplementation ◽  
Trial Performance

Six days of dietary nitrate supplementation in the form of beetroot juice (~0.5 L/d) has been reported to reduce pulmonary oxygen uptake (VO2) during submaximal exercise and increase tolerance of high-intensity work rates, suggesting that nitrate can be a potent ergogenic aid. Limited data are available regarding the effect of nitrate ingestion on athletic performance, and no study has investigated the potential ergogenic effects of a small-volume, concentrated dose of beetroot juice. The authors tested the hypothesis that 6 d of nitrate ingestion would improve time-trial performance in trained cyclists. Using a double-blind, repeated-measures crossover design, 12 male cyclists (31 ± 3 yr, VO2peak = 58 ± 2 ml · kg−1 · min−1, maximal power [Wmax] = 342 ± 10 W) ingested 140 ml/d of concentrated beetroot (~8 mmol/d nitrate) juice (BEET) or a placebo (nitrate-depleted beetroot juice; PLAC) for 6 d, separated by a 14-d washout. After supplementation on Day 6, subjects performed 60 min of submaximal cycling (2 × 30 min at 45% and 65% Wmax, respectively), followed by a 10-km time trial. Time-trial performance (953 ± 18 vs. 965 ± 18 s, p < .005) and power output (294 ± 12 vs. 288 ± 12 W, p < .05) improved after BEET compared with PLAC supplementation. Submaximal VO2 was lower after BEET (45% Wmax = 1.92 ± 0.06 vs. 2.02 ± 0.09 L/min, 65% Wmax 2.94 ± 0.12 vs. 3.11 ± 0.12 L/min) than with PLAC (main effect, p < .05). Wholebody fuel selection and plasma lactate, glucose, and insulin concentrations did not differ between treatments. Six days of nitrate supplementation reduced VO2 during submaximal exercise and improved time-trial performance in trained cyclists.

The Effects of EGCG on Fat Oxidation and Endurance Performance in Male Cyclists

2009 ◽  
Vol 19 (6) ◽  
pp. 624-644 ◽  
Author(s):  
Sara Dean ◽  
Andrea Braakhuis ◽  
Carl Paton
Keyword(s):  
Fatty Acids ◽  
Green Tea ◽  
Time Trial ◽  
Endurance Performance ◽  
Fat Oxidation ◽  
Cycling Performance ◽  
Green Tea Extract ◽  
Endurance Capacity ◽  
Caffeine Ingestion ◽  
Tea Extract

Researchers have long been investigating strategies that can increase athletes’ ability to oxidize fatty acids and spare carbohydrate, thus potentially improving endurance capacity. Green-tea extract (epigallocatechin-3-gallate; EGCG) has been shown to improve endurance capacity in mice. If a green-tea extract can stimulate fat oxidation and as a result spare glycogen stores, then athletes may benefit through improved endurance performance. Eight male cyclists completed a study incorporating a 3-way crossover, randomized, placebo-controlled, double-blinded, diet-controlled research design. All participants received 3 different treatments (placebo 270 mg, EGCG 270 mg, and placebo 270 mg + caffeine 3 mg/kg) over a 6-day period and 1 hr before exercise testing. Each participant completed 3 exercise trials consisting of 60 min of cycling at 60% maximum oxygen uptake (VO2max) immediately followed by a self-paced 40-km cycling time trial. The study found little benefit in consuming green-tea extract on fat oxidation or cycling performance, unlike caffeine, which did benefit cycling performance. The physiological responses observed during submaximal cycling after caffeine ingestion were similar to those reported previously, including an increase in heart rate (EGCG 147 ± 17, caffeine 146 ± 19, and placebo 144 ± 15 beats/min), glucose at the 40-min exercise time point (placebo 5.0 ± 0.8, EGCG 5.4 ± 1.0, and caffeine 5.8 ± 1.0 mmol/L), and resting plasma free fatty acids and no change in the amount of carbohydrate and fat being oxidized. Therefore, it was concluded that green-tea extract offers no additional benefit to cyclists over and above those achieved by using caffeine.

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