Xtend Endurance and Recovery Enhancer by Scivation
Scivation Xtend Refreshing Lemonade scientifically advanced endurance and recovery enhancer is a precise, scientific blend of Energy Aminos consisting of the proven 2:1:1 ratio of Branched Chain Amino Acids (L-Leucine, L-Isoleucine and L-Valine), Glutamine, Citrulline Malate, and Vitamin B6 that will give you the energy you need to maximize your training while enhancing recovery at the same time.
XTEND has been scientifically provent to help:
- Speed Recovery.
- Enhance ATP production and promote cell volumization.
- Reduce muscle breakdown levels.
- Reduce fatigue and lactic acid levels for longer, more intense training.
- Support lean body mass along with immune and digestive health.
- Promote vasodilation which can lead to better assimilation and abosorption of protein.
- Support Optimal Growth hormone levels.
Citrulline Malate and BCAA's
Citrulline malate (CM) is a combination of two compounds that occur naturally in the human body. Malate is an intermediate in the so-called tricarboxylic acid cycle (TCA). ATP, which the body uses as a source of energy, is produced via the TCA when oxygen is abundant. (In reality, no ATP is produced directly from the TCA, although this statement is often heard. Rather, reduced coenzymes, NADH, are used to generate ATP in electron transport chain powered oxidative phosphorylation.) This is so called aerobic energy production.
Tricarboxylic acid cycle (TCA) at a glance. Each kind of major fuel is converted to acetyl groups, which are handled by attachment to a particular coenzyme known as coenzyme A. Ultimately ATP is produced from NADH generated by the TCA.
Malate is dehydrogenated in the TCA cycle to oxaloacetate, the concentration of which is one of the most critical controls of the rate of aerobic ATP production. During prolonged aerobic activity, and in patients suffering from malate deficiency, malate becomes depleted and the TCA is unable to produce ATP fast enough to meet the demands of working muscle. One classic disease characterized by malate deficiency is fibromyalgia. When patients suffering with this disease are given malate, their energy levels improve dramatically.
Thus far we have only addressed the role of malate in enhancing ATP production during aerobic metabolism. What about citrulline? Citrulline is a non-essential amino acid produced from glutamine in the body. Citrulline is involved in the so-called urea cycle, which is responsible for the removal of excess nitrogen from the breakdown of amino acids. Were excessive levels of nitrogen to accumulate in the body, ammonia toxicity would develop. Besides stimulating hepatic ureogenesis , citrulline also promotes the renal reabsorption of bicarbonates. The latter acts as a buffer against lactic acidosis, which also helps to stave off fatigue. In fact there has been some debate over the years whether citrulline or malate is primarily responsible of prolonging endurance (3). The consensus now seems to be that the two compounds work in concert, with malate maintaining TCA intermediates and allowing for increased ATP production, and citrulline buffering against lactic acid and ammonia buildup.
So we have seen that citrulline malate seems to be a worthwhile adjunct to any supplement protocol, especially where aerobic performance and fatigue resistance are important.
THE ROLE OF BRANCHED-CHAIN AMINO ACIDS IN FATIGUE RESISTANCE
The branched-chain amino acids isoleucine, leucine, and valine are widely used among athletes for their protein sparing effect.
L-leucine is also known as 2-amino-4-methylvaleric acid, alpha-am:" ":cular weight is 131.17 daltons. Its structural formula is
L-isoleucine is also known as 2-amino-3-methylvaleric acid, alpha-amino-beta-methylvaleric acid and (2S, 3S)-2-amino-3-methylpentanoic acid. It is abbreviated as Ile or by its one letter abbreviation I. Its molecular formula is C 6H13NO2, and its molecular weight is 131.17 daltons. Its structural formula is
L-valine is also known as 2-aminoisovaleric acid, 2-amino-3-methylbutyric acid, alpha-aminoisovaleric acid and (S)-2-amino-3-methylbutanoic acid. It is abbreviated as Val, and its one letter abbreviation is V. Its molecular formula is C5H11NO2, and its molecular weight is 117.15 daltons. Its structural formula is:
A number of studies have shown that branched chain amino acids exert both an anabolic and ergogenic effect.
TNF-alpha and BCAAs
Tumor necrosis factor alpha (TNF-alpha) is a cytokine produced by immune cells in the body called monocytes and macrophages. TNF exerts a number of deleterious effects on the body, including muscle wasting, and locally produced igf-1 suppression, and general fatigue. While usually associated with illness, TNF-alpha levels are also high in hypogonadal patients and overtrained athletes. In one study, lipopolysachharide, a bacterial toxin that elevates TNF-alpha, was administered to rats. One group of rats was fed citrulline malate, and one group served as controls. The citrulline malate group performed much better on treadmill tests and exhibited less overall fatigue that did the controls (8).
These results may be of significance to overtrained athletes in whom TNF-alpha is elevated, and in anabolic steroid using athletes who are essentially hypogonadal post cycle. Citrulline malate may help alleviate the fatigue associated with both these conditions.
BCAAs may suppress TNF-alpha and its damaging effects on muscle tissue as well. In one study in animals, TNF-alpha was administered and diaphragm tissue was examined post mortem. Chronic TNF-alpha treatment produced a significant decline in the synthesis of all types of myofibrillar proteins, namely heavy chain myosin, light chain myosin and G-actin. TNF-alpha impaired peptide-chain initiation in diaphragm muscle was reversed by the branched-chain amino acids (BCAA) therapy of TNF-alpha treated rats. The authors concluded that
In addition "to blocking the muscle wasting catabolic effects of pro-inflammatory cytokines, BCAAs also seem to fight a tug of war with catabolic glucocorticoids. This suggests that under conditions such as stress or overtraining, BCAAs might help alleviate the catabolic effects of cortisol (10).
Leucine activates system A amino acid transport in skeletal muscle cells.
Just as glucose uptake into cells is dependent upon a family of so called GLUT (Glucose Transporters), amino acids are transported into cells by a distinct family of transporters. One main transport system is the so-called System A. In vitro studies have shown that leucine upregulates System A transporters, allowing for greater entry of a number of amino acids into muscle cells (11). It should be noted that one of the anabolic effects of IGF-1 is believed to be upregulation of this same transport system. So in this sense leucine may share at least one of the anabolic effects associated with insulin like growth factor.
So we have seen that amino acids, and leucine in particular are capable of activat:" ":is a common intermediate in both nutrient and hormone signal transduction pathways. Signaling through mTOR is enhanced by nutrients and anabolic hormones, such as insulin or IGF-I and repressed by elevation of cAMP or activation of AMPK suggesting that one function of mTOR is to integrate the anabolic response to nutrients and insulin and the catabolic response to counter-regulatory hormones, such as glucagon...Although other amino acids have been shown to increase signaling through mTOR, leucine is arguably the most potent of the amino acids in activating the pathway."
The importance of leucine to post resistance exercise recovery is highlighted in another recently published study where participants undertook a bout of resistance exercise and were fed either carbohydrates alone, carbohydrates plus whey protein, or a combination of carbs, whey and leucine (13). Subjects received a beverage volume of 3 ml.kg-1 every 30 minutes to ensure a given dose of 0.3 g carbohydrate.kg-1 (50% as glucose and 50% as maltodextrin) and 0.2 g.kg-1 of a protein hydrolysate [whey] every h, with or without the addition of 0.1 g.kg-1.h-1 leucine. To quote from the report,
"Mixed muscle [protein synthesis rate], measured over a 6h period of post-exercise recovery, was significantly greater in the CHO+PRO+leu trial compared to the CHO, with intermediate values observed in the CHO+PRO trial . We conclude that the co-ingestion of protein and leucine stimulates muscle protein synthesis and optimizes whole-body protein balance when compared to the intake of carbohydrate only."
Before leaving the subject of BCAAs and citrulline, it might be worthwhile to briefly discuss the role of another amino acid, glutamine that is both quite popular and controversial as a supplement. The bulk of the research suggests that under normal circumstances the body is capable of making adequate amounts of glutamine from the branched chain amino acids discussed above. However, when the body is taxed by illness, sepsis, cancer, cachexia, and trauma, and perhaps chronic overtraining, the body may become depleted in BCAAs. The BCAAs released to circulation may be used for protein synthesis or synthesis of alanine and glutamine. Glutamine and/or alanine infusion has an inhibitory effect on the breakdown of body proteins and decreases BCAA catabolism in postabsorptive control, endotoxemic, and irradiated rats. This helps preserve muscle mass under these conditions (14). So while glutamine supplementation might not be absolutely necessary with an adequate intake of amino acids, especially BCAAS, it’s hard to see how glutamine supplementation could hurt, and might actually be beneficial.