Davan cited these references to support the benefits of the supplements he chooses. NONE of the references cited support any performance enhancement effects, and in fact indicate there are none in a couple.
Derave W, Ozdemir MS, Harris R, Pottier A, Reyngoudt H, Koppo K, Wise JA, Achten E. (August 9 2007). “Beta-alanine supplementation augments muscle carnosine content and attenuates fatigue during repeated isokinetic contraction bouts in trained sprinters”. J Appl Physiol 103: 1736
[/quote]From the study…”the increase in muscle carnosine did not improve isometric endurance or 400-m race time.” This study indicates there is no benefit to sprinters in taking beta-alanine. I actually think beta-alanine has potential, but this study does not support that contention.
Ostojic SM. Yohimbine: the effects on body composition and exercise
performance in soccer players. Res Sports Med. 2006 Oct-Dec;14(4):289-99.
From the study…”There were no changes in exercise performance indicators (bench and leg press, vertical jump, dribble and power test results, shuttle run) within or between. trials (p > 0.05). No subject reported any side effects from yohimbine. The results of the current study indicate that supplementation with yohimbine combined with resistance training does not significantly alter the body mass, muscle mass, or performance indicators in professional soccer players.”
Magill RA, Waters WF, Bray GA, Volaufova J, Smith SR, Lieberman HR, McNevin N,
Ryan DH. Effects of tyrosine, phentermine, caffeine D-amphetamine, and placebo on
cognitive and motor performance deficits during sleep deprivation. Nutr Neurosci.
Doesn’t address any athletic performance measures, period. Has absolutely nothing to do with sprint performance. This study does nothing to back up your claim that Tyrosine is a performance enhancer.
Belza A, Toubro S, Astrup A. The effect of caffeine, green tea and tyrosine on
thermogenesis and energy intake. Eur J Clin Nutr. 2009 Jan;63(1):57-64. Epub 2007
Sep 19. PubMed PMID: 17882140.
From the study…”The thermogenic responses to GTE and tyrosine were not significantly different from placebo.”[/b][/i][/i] No differences from placebo, meaning no effect…and this was simply about metabolism…doesn’t even begin to address athletic enhancement of any kind, much less sprint performance.
Davan, your already limited credibility suffers greatly with a post like this. You blast me for not reading the studies I post (which I DO and which DO address the issue being discussed and DO show statistically relevent enhancement in not only athletic performance in general, but sprint performance specifically, and then you post this drivel. Not one study you cite supports any athletic enhancement benefits at all from any of these substances, and two actually indicate that there are NO benefits derived from the substances studied. Did YOU read the studies YOU posted in support of YOUR opinions, or did you just not undestand them?