J’en avais déjà parlé dans un podcast (mais tout le monde ne supporte pas)

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Effect of l-ornithine hydrochloride ingestion on intermittent maximal anaerobic cycle ergometer performance and fatigue recovery after exercise
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY         Shinichi Demura, Koji Morishita, Takayoshi Yamada, Shunsuke Yamaji and Miho Komatsu

l-Ornithine plays an important role in ammonia metabolism via the urea cycle. This study aimed to examine the effect of l-ornithine hydrochloride ingestion on ammonia metabolism and performance after intermittent maximal anaerobic cycle ergometer exercise. Ten healthy young adults (age, 23.8 ± 3.9 year; height, 172.3 ± 5.5 cm; body mass, 67.7 ± 6.1 kg) with regular training experience ingested l-ornithine hydrochloride (0.1 g/kg, body mass) or placebo after 30 s of maximal cycling exercise. Five sets of the same maximal cycling exercise were conducted 60 min after ingestion, and maximal cycling exercise was conducted after a 15 min rest. The intensity of cycling exercise was based on each subject’s body mass (0.74 N kg−1). Work volume (watt), peak rpm (rpm) before and after intermittent maximal ergometer exercise and the following serum parameters were measured before ingestion, immediately after exercise and 15 min after exercise: ornithine, ammonia, urea, lactic acid and glutamate. Peak rpm was significantly greater with l-ornithine hydrochloride ingestion than with placebo ingestion. Serum ornithine level was significantly greater with l-ornithine hydrochloride ingestion than with placebo ingestion immediately and 15 min after intermittent maximal cycle ergometer exercise. In conclusion, although maximal anaerobic performance may be improved by l-ornithine hydrochloride ingestion before intermittent maximal anaerobic cycle ergometer exercise, the above may not depend on increase of ammonia metabolism with l-ornithine hydrochloride.

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Effects of Chrysin Supplementation on Blood and Urinary Testosterone Levels in Human
Medicine & Science in Sports & Exercise: May 2011 - Volume 43 - Issue 5 - p 845     Hung, Tzu-Hsiang; Lin, Yi-An; Hsu, Ku-Fu; Lu, Ching-Yi; Hsu, Mei-Chich FACSM

In human, aromatase converts androstenedione and testosterone into estrone and estradiol, respectively. Chrysin has been shown as a potent aromatase inhibitor, which may increase the concentration of serum and urinary testosterone and lead to violate the doping control rule. However, the effects of the chrysin supplementation on blood and urinary testosterone levels in human have yet to be elucidated.
PURPOSE: This study was to investigate whether the chrysin supplementation would increase serum testosterone by altering the synthesis of the testosterone pathway. Moreover, the ratio of testosterone to epitestosterone in urine was measured.
METHODS: Twenty throwing athletes (14 males, 6 females) of National Taiwan Sport University participated in this study. Subjects were randomly assigned in pairs (matched for athletic events) by use of a double blind design to receive chrysin (group C) or placebo (group P). All subjects were oral 3,000 mg of chrysin capsules or equal dosage of placebo per day for 21 days. Blood and urine samples were collected at day 1, 8, and 22 in the morning after overnight fasting. Blood samples were analyzed for serum testosterone, free testosterone, and estradiol. Urinary testosterone and epitestosterone was measured by GC/MS. A two-way mixed designed analysis of variance (ANOVA), with one within-subject factor (time trial), one between-subject factor (group C or P), and their interaction, was used to determine the overall 21-day treatment effect and level of significance. All values were expressed as the mean ± SD. Values of P

<0.05 were considered significant.
RESULTS: The data showed no significant difference in blood biomarkers between the groups C and P (testosterone: 4.7±2.3 vs. 4.3±1.6 ng/mL; free testosterone: 12.5±5.5 vs. 11.4± 3.5 pg/mL; estradiol: 43.2±22.1 vs. 49.6±18.7 pg/mL, p >

.05). Urinary data of testosterone/epitestosterone ratio was less than 4.
CONCLUSION: Our data demonstrated that chrysin supplementation for 21 days may not increase serum and urinary testosterone levels.

Effects of Chrysin Supplementation on Body Composition, Muscle Strength, and Exercise Performance in Throwing Athletes
Medicine & Science in Sports & Exercise: May 2011 - Volume 43 - Issue 5 - p 849 Lin, Yi-An; Hung, Tzu-Hsiang; Hsu, Ku-Fu; Lu, Ching-Yi; Huang, Chi-Chang; Hsu, Mei-Chich

Previous studies have suggested that chrysin (5,7-dihydroxyflavone) is a potent aromatase inhibitor in vitro, which may increase serum testosterone concentration. Testosterone is a highly anabolic hormone which can stimulate the growth of muscle mass and strength. However, the effects of the chrysin supplementation on body composition, muscle strength, and exercise performance in human have not yet to be discussed.
PURPOSE: To investigate whether the chrysin supplementation would improve body composition, muscle strength, and exercise performance by altering the synthesis of testosterone.
METHODS: Twenty throwing athletes (14 males, 6 females) of National Taiwan Sport University participated in this study. Subjects were randomly assigned in pairs (matched for athletic events) by use of a double blind design to receive chrysin (group C) or placebo (group P). All subjects were given oral chrysin doses of 3 g or placebo per day for 21 days. Body composition, muscle strength and exercise performance were also assessed at day 1, 8, and 22 in the morning. Body composition was evaluated by body weight, body mass index (BMI), body fat percentage, skinfold thickness, and body circumference. Muscle strength and exercise performance including maximal isometric force of quadriceps and biceps, vertical jump, standing broad jump, and medicine ball chest pass test were performed. A two-way mixed design analysis of variance (ANOVA) with one within-subject factor (time trial), one between-subject factor (group C or P), and their interaction were used to determine the overall 21-day treatment effect and level of significance. All data were expressed as mean ± SD and values of P<0.05 were considered significant.
RESULTS: BMI was reduced in day 8 and 22 at group C (32.1 ± 4.9 vs. 31.9 ± 4.8 kg/m2; P<0.05). Waist circumference was reduced in day 22 at group C (97.1 ± 11.4 vs. 95.4 ± 10.6 cm; P<0.05). The data showed no significant difference in body composition, muscle strength, and exercise performance between groups C and P.
CONCLUSIONS: Our data provided by a human study, suggest that chrysin supplementation for 21 days may not improve body composition, muscle strength, and exercise performance.

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Ca parait évident mais ça n’a pas l’air de l’être pour tous

The Effects of Sodium Bicarbonate Ingestion on Exhaustive Bench Press Performance
Medicine & Science in Sports & Exercise:  May 2011 - Volume 43 - Issue 5 - pp 847-848     Page, Richard; Siegler, Jason C. FACSM
Sodium bicarbonate (NaHCO3) has been shown to be an effective ergogenic aid in attenuating to the deleterious perturbations in acid-base status associated with high intensity exercise. However, given the plethora of studies that exist only a limited number have assessed its efficacy in enhancing resistance exercise performance.
PURPOSE: To examine the effects of NaHCO3 supplement on exhaustive bench press performance after varying recovery times between sets.
METHODS: Eight resistance trained male subjects performed six single blind, randomized trials on the bench press (three sets at a constant load of 70% of one repetition maximum (RM), the final of which completed to failure with rest intervals of 60, 120 or 180 seconds (s) between sets) 120 minutes post NaHCO3 (0.3 g·kg-1) or placebo (NaCl, 0.045 g·kg-1) ingestion. Capillary blood samples were obtained pre and post ingestion, and following the final exhaustive set. All metabolic data were assessed via a two-way ANOVA and performance data by a three-way ANOVA, both with repeated measures.
RESULTS: Post hoc analysis revealed blood acid-base status (pH, bicarbonate [HCO3-] and base excess [BE]) was significantly elevated (p < 0.05) following NaHCO3 ingestion in comparison to placebo. Although significantly lower than pre exercise (p < 0.05), post trial pH, HCO3- and BE values remained elevated in the NaHCO3 treatments compared to placebo (p < 0.05). Subsequent analysis revealed no significant interaction or main effects for treatment on the number of reps performed to exhaustion during the final set (p > 0.05).

However, the number of reps performed during the final set to failure increased proportionally to the increasing length of the rest interval (60s: 8.4 ± 3.7, 120s: 11.4 ± 3.3, 180s: 12.9 ± 3.5 p < 0.05).

CONLUSION: Thus, although NaHCO3 attenuated metabolic acidosis, it had no effect on skeletal muscle contractile function or recovery intervals between sets.

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Effects of Sodium Bicarbonate Supplementation with Acute Caffeine Ingestion on Simulated 3-KM Cycle Performance
Medicine & Science in Sports & Exercise: May 2011 - Volume 43 - Issue 5 - p 847   Ferguson, Brian S.; Greer, Felicia A.; Morales, Jacobo O.; Anderson, Tim R.

Sodium bicarbonate (SB) has been reported to increase extracellular pH and base excess after supplementation. This can delay the onset of fatigue and maintain a more favorable pH for ongoing glycolytic metabolism. Enhanced performance is also associated with caffeine (CAFF) as mediated through the CNS and periphery. There is limited information about the combined use of these two ergogenic aids. PURPOSE: To examine the effects of short-term SB supplementation combined with acute CAFF ingestion on simulated time trial (TT) performance and blood lactate (BL) accumulation in trained male cyclist’s.
METHODS: Male volunteers (n=16, 38.25 + 5.25 yrs, 60.39 + 5.97 ml/kg/min), in a double-blind, placebo (PL) controlled, crossover protocol, were randomly assigned four treatments (SB+CAFF, CAFF, SB, PL). Subject’s personal bicycles were mounted to a stand with a PowerTap SL+ hub, computer, and PowerTap coded heart rate monitor. Day 1 subject’s ingested 0.3 g/kg body weight (BW) either (SB) or (PL) in four equal doses. The final dose was taken two hours before TT. Day 2, one hour prior to TT, subjects ingested 6 mg/kg BW either CAFF or PL. After a 15 minute warm-up subjects performed a simulated 3-km TT. Finger prick BL samples were taken prior to and one hour post ingestion of CAFF or PL. Post TT, BL samples were taken immediately after exercise then and at three and ten minutes postexercise. During each TT, time to complete 3-km was measured in addition to average and peak values for power, speed, and heart rate. Data was analyzed using one-way ANOVA (p< 0.05).
RESULTS: Mean TT was fastest with SB+CAFF (300.25 + 33.14s), followed by CAFF (306.00 + 31.98s), SB (311.19 + 32.47s) and PL (316.00 + 32.02s). Three minutes post TT, BL concentrations for SB+CAFF (13.72 + 1.92 mmol/L, p<0.05) were higher than PL (11.56 + 0.07 mmol/L, p<0.05). At 10 minutes post TT, BL concentrations were higher for SB+CAFF (11.99 + 2.52 mmol/L, p<0.05) than CAFF (8.15 + 2.09mmol/L, p<0.05), SB (8.99 + 1.97 mmol/L, p<0.05) or PL (7.92 + 2.13 mmol/L, p<0.05).
CONCLUSIONS: These data show a potential for performance enhancement through the combined supplementation of CAFF and SB as well as significantly higher postexercise BL concentrations.

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Effects Of Combined Creatine And Sodium Bicarbonate Supplementation On Repeated Sprint Performance In Trained Men
Medicine & Science in Sports & Exercise: May 2011 - Volume 43 - Issue 5 - pp 845-846   Barber, James J.; McDermott, Ann Y.; McGaughey, Karen; Olmstead, Jennifer D.; Hagobian, Todd A.

Creatine and sodium bicarbonate supplementation independently increase repeated sprint performance. It remains unclear whether combining these two supplements has an additional benefit on performance.
PURPOSE: To determine whether a combined supplementation of creatine and sodium bicarbonate, compared to creatine supplementation alone, would further increase repeated sprint performance.
METHODS: Thirteen healthy, fit men (21.1 ± 0.6 yr, 23.5 ± 0.5 kg/m2, 66.7 ± 5.7 ml/kg-min) completed 3 conditions in a double-blinded, crossover fashion: 1) Placebo (5 g maltodextrin + 0.5 g/kg maltodextrin), 2) Creatine (Cr; 5 g + 0.5 g/kg maltodextrin), and 3) Creatine plus sodium bicarbonate (Cr+Sb; 5g + 0.5 g/kg sodium bicarbonate). The additional 0.5 g/kg of maltodextrin in placebo and Cr was given to mask for the sodium bicarbonate supplement. Each condition consisted of supplementation for 2 days followed by a 3-week washout. In the morning after each condition, peak power (W), mean power (W), relative peak power (W/kg), and blood concentrations of bicarbonate were assessed during six 10-second repeated Wingate sprint tests on a cycle ergometer with a 60-second rest period between each sprint using a 2-factor ANOVA (condition x time).
RESULTS: Compared to placebo, peak power and mean power were not different in Cr, but was significantly higher (P<0.05) in Cr+Sb (3%, 5%, respectively). Compared to placebo, relative peak power was significantly higher (P<0.05) in Cr (4%) and Cr+Sb (7%). Relative peak power was significantly lower (P<0.05) in sprints 4-6, compared to sprint 1, in both placebo and Cr. Relative peak power was not different in sprints 4 and 5 compared to sprint 1, but was lower in sprint 6 in Cr+Sb (P=0.002). Baseline bicarbonate concentrations (before sprint 1) were significantly higher in Cr+Sb (10%), compared to placebo and Cr, and mean concentrations remained higher after sprint 6, although not significantly (P>0.05).
CONCLUSION: Combining creatine and sodium bicarbonate supplementation increased peak and mean power, had the greatest attenuation of decline in relative peak power over the six repeated sprints, and maintained higher baseline bicarbonate levels. These data suggest that combining these two supplements may be advantageous for athletes participating in high-intensity, intermittent exercise.

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The Effect Of Lactate On Proliferation And Differentiation Behaviour Of C2c12 And Primary Human Myoblasts
Medicine & Science in Sports & Exercise: May 2011 - Volume 43 - Issue 5 - p 411   Willkomm, Lena; Elsen, Manuela; Borosch, Sebastian; Jung, Raphael; Bloch, Wilhelm

Lactate (La) has long been considered as a waste product of energy metabolism and the cause of decrease in muscle pH and hence muscle fatigue. This idea has changed massively in the past. Now it is known that La is rather an intermediate of glucose metabolism as well as it has been termed Lactormon for it has signalling properties inducing gene expression for skeletal muscle adaptation. It has been shown to increase MCT content as well as to increase mitochondrial biogenesis. Such skeletal muscle adaptation is one of the major foci in sports medicine. Numerous adaptational mechanisms and signalling pathways have been described in the literature, investigating among other mechanical, metabolical, nutritional, and hormonal stimuli and their effects for the improvement of physiological functioning of skeletal muscle tissue. La, as a metabolic stimulus, has not yet been investigated extensively in this context.
PURPOSE: We investigated the effects of different lactate concentrations on the proliferation status and differentiation behaviour of C2C12 mouse immortal and primary human myoblasts.
METHODS: C2C12 mouse and primary human myoblasts were constantly incubated with differentiation medium containing different lactate concentrations (10 mM, 20 mM) at 37°C and 5% CO2 over a time period of 15 days. Cells were fixed using 4% PFA in PBS for immunocytochemical staining for Ki67, activated Caspase-3, F5D (myogenin) and Mf-20 (myosin heavy chain). Additionally, cell lysates were made for Western Blot analysis using the same markers as for immunostaining. Furthermore, we repeated the experiments with an intermittent incubation of 2 h every day to simulate a more realistic training situation.
RESULTS: Densitometrical analysis of cells stained for Ki67 showed a significant decrease if treated with La in a dose-dependent manner. Controversially, apoptotic induction by activated caspase-3 was increased if treated with La. Differentiation was shown to be delayed, but not decreased if cells received the La intervention.
CONCLUSION: Lactate seems to exhibit an inhibitory effect on the proliferation and apoptotic behaviour of C2C12 and primary human myoblasts. Furthermore, differentiation seems to be delayed but not reduced in a dose-dependent manner.

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