^ Jump up to: a b Barcelos RP, Stefanello ST, Mauriz JL, Gonzalez-Gallego J, Soares FA (2016). "Creatine and the Liver: Metabolism and Possible Interactions". Mini Reviews in Medicinal Chemistry. 16 (1): 12–8. doi:10.2174/1389557515666150722102613. PMID 26202197. The process of creatine synthesis occurs in two steps, catalyzed by L-arginine:glycine amidinotransferase (AGAT) and guanidinoacetate N-methyltransferase (GAMT), which take place mainly in kidney and liver, respectively. This molecule plays an important energy/pH buffer function in tissues, and to guarantee the maintenance of its total body pool, the lost creatine must be replaced from diet or de novo synthesis.
In regard to bioenergetics, phosphorylated cyclocreatine appears to have less affinity for the creatine kinase enzyme than phosphorylated creatine in terms of donating the high energy phosphate group (about 160-fold less affinity) despite the process of receiving phosphorylation being similar. When fed to chickens, phosphorylated cyclocreatine can accumulate up to 60mM in skeletal muscle, which suggests a sequestering of phosphate groups before equilibrium is reached. Cyclocreatine still has the capacity to donate phosphate, however, as beta-adrenergic stimulated skeletal muscle (which depletes ATP and glycogen) exhibits an attenuation of glycogen depletion (indicative of preservation of ATP) with phosphocreatine.
In regard to practical interventions, concurrent glycogen loading has been noted to increase creatine stores by 37-46% regardless of whether the tissue was exercised prior to loading phase. It is important to note, however, that creatine levels in response to the creatine loading protocol were compared in one glycogen-depleted leg to the contralateral control leg, which was not exercised. This does not rule out a possible systemic exercise-driven increase in creatine uptake, and the increase in creatine noted above was larger than typically seen with a loading protocol (usually in the 20-25% range). Consistent with an exercise-effect, others have reported that exercise itself increases creatine uptake into muscle, reporting 68% greater creatine uptake in an exercised limb, relative to 14% without exercise.
Do a single set of repetitions. Theories on the best way to approach weight training abound, including countless repetitions and hours at the gym. But research shows that a single set of exercise with a weight that fatigues your muscle after about 12 to 15 repetitions can build muscle efficiently in most people and can be as effective as three sets of the same exercise.
Women who train hard and reach low body fat levels, say under 10 percent, may be at risk of losing their periods as a result of hormonal disruption to estrogen production. Exercise-induced estrogen declines can result in bone loss in a way similar to that which occurs at the menopause. Loss of periods from athletic training is not uncommon but does require that you see a doctor, or better still, a sports physician and sports nutritionist to assess what is required to address the problem. Calcium supplements may be a part of the solution if bone health is likely to be affected.
By increasing the overall pool of cellular phosphocreatine, creatine supplementation can accelerate the reycling of ADP into ATP. Since ATP stores are rapidly depleted during intense muscular effort, one of the major benefits of creatine supplementation is its ability to regenerate ATP stores faster, which can promote increased strength and power output. Over 95% of creatine is stored in muscle at a maximum cellular concentration of 30uM. Creatine storage capacity is limited, though it increases as muscle mass increases. A 70 kg male with an average physique is assumed to have total creatine stores of approximately 120g. The body can store a lot more energy as glycogen in the liver, brain, and muscles, and even more as fat.
It is regularly reported that creatine supplementation, when combined with heavy resistance training leads to enhanced physical performance, fat free mass, and muscle morphology [18-22]. A 2003 meta analysis  showed individuals ingesting creatine, combined with resistance training, obtain on average +8% and +14% more performance on maximum (1RM) or endurance strength (maximal repetitions at a given percent of 1RM) respectively than the placebo groups. However, contradicting studies have reported no effects of creatine supplementation on strength performance. Jakobi et al  found no effects of a short term creatine loading protocol upon isometric elbow flexion force, muscle activation, and recovery process. However, this study did not clearly state if creatine supplementation was administered concurrent with resistance training. Bemben et al  have shown no additional benefits of creatine alone or combined with whey protein for improving strength and muscle mass after a progressive 14 weeks (3 days per week) resistance training program in older men. These conflicting results can be explained by the possibility that the supplemented groups were formed by a greater amount of non-responders or even because creatine supplementation was administered on the training days only (3 times a week). This strategy has not been adequately tested as effective in middle aged and older men for maintaining post loading elevated creatine stores .
Both testosterone and 5α-DHT are metabolized mainly in the liver. Approximately 50% of testosterone is metabolized via conjugation into testosterone glucuronide and to a lesser extent testosterone sulfate by glucuronosyltransferases and sulfotransferases, respectively. An additional 40% of testosterone is metabolized in equal proportions into the 17-ketosteroids androsterone and etiocholanolone via the combined actions of 5α- and 5β-reductases, 3α-hydroxysteroid dehydrogenase, and 17β-HSD, in that order. Androsterone and etiocholanolone are then glucuronidated and to a lesser extent sulfated similarly to testosterone. The conjugates of testosterone and its hepatic metabolites are released from the liver into circulation and excreted in the urine and bile. Only a small fraction (2%) of testosterone is excreted unchanged in the urine.
Beta-alanine is a naturally occurring non-essential amino acid that comes into the body through foods that are rich in protein. The performance-enhancing aspect of beta-alanine (BA) is due to its ability to increase intra-muscular levels of carnosine. Increasing beta-alanine through supplementation may raise carnosine levels by over 60 percent in as quickly as four weeks.
Kornblum, C., Schroder, R., Muller, K., Vorgerd, M., Eggers, J., Bogdanow, M., Papassotiropoulos, A., Fabian, K., Klockgether, T., and Zange, J. Creatine has no beneficial effect on skeletal muscle energy metabolism in patients with single mitochondrial DNA deletions: a placebo-controlled, double-blind 31P-MRS crossover study. Eur J Neurol 2005;12:300-309. View abstract.
Now, creatine combines with inorganic phosphate to form phosphocreatine in a reaction accelerated by an enzyme named creatine kinase. Most of us increase our phosphocreatine stores when we consume creatine. In turn, our fortified phosphocreatine stores can donate additional high-energy phosphate groups during very energy-demanding activities, more efficiently recycling ATP from ADP. This is the main way creatine supplementation improves high-intensity exercise performance.
Abnormally high levels of testosterone could be the result of an adrenal gland disorder, or even cancer of the testes. High levels may also occur in less serious conditions. Congenital adrenal hyperplasia, which can affect males and females, is a rare but natural cause for elevated testosterone production. Your doctor may order other tests if your levels are exceedingly high.
Activation of NMDA receptors is known to stimulate Na+,K+-ATPase activity secondary to calcineurin, which which has been confirmed with creatine in hippocampal cells (0.1-1mM trended, but 10mM was significant). This is blocked by NMDA antagonists. This increase in Na+,K+-ATPase activity is also attenauted with activation of either PKC or PKA, which are antagonistic with calcineurin.
There is a dirty little secret about testosterone cream that almost no one knows, and I’m going to share it here. Please don’t abuse it. If you take a vanishingly small dose of testosterone cream and apply it to your labia and the vulva (or your partner’s), you will witness a form of vasodilation rarely seen no matter how good you are in bed. It has a profound local effect and will produce a night you won’t forget for years.
There are countless reasons to lift weights and build strong muscles, including injury prevention, improved bone density, and a lower risk for type 2 diabetes and other diseases—not to forget that bad-ass feeling you get when you can haul a giant piece of furniture up the stairs all by yourself. Another often-cited benefit to strength training is that it will increase your metabolism. But how much does your metabolism increase with strength training? The answer depends on many different factors.
An exercise should be halted if marked or sudden pain is felt, to prevent further injury. However, not all discomfort indicates injury. Weight training exercises are brief but very intense, and many people are unaccustomed to this level of effort. The expression "no pain, no gain" refers to working through the discomfort expected from such vigorous effort, rather than to willfully ignore extreme pain, which may indicate serious soft tissue injuries. The focus must be proper form, not the amount of weight lifted.
However, testosterone is only one of many factors that aid in adequate erections. Research is inconclusive regarding the role of testosterone replacement in the treatment of erectile dysfunction. In a review of studies that looked at the benefit of testosterone in men with erection difficulties, nearly half showed no improvement with testosterone treatment. Many times, other health problems play a role in erectile difficulties. These can include:
Perform bent over rows to work your back. Stand with your feet shoulder-width apart, about 6 to 10 inches (15–25 cm) behind the barbell or two dumbbells. Bend slightly at the knees but keep your shins vertical. Bend forward at the waist with your spine and head straight. Lift the weight with an overhand grip up to your lower chest or upper abdomen. Lower slowly until your arms are nearly extended, without touching the ground. 3 x 8.
Discomfort can arise from other factors. Individuals who perform large numbers of repetitions, sets, and exercises for each muscle group may experience a burning sensation in their muscles. These individuals may also experience a swelling sensation in their muscles from increased blood flow (the "pump"). True muscle fatigue is experienced as a marked and uncontrollable loss of strength in a muscle, arising from the nervous system (motor unit) rather than from the muscle fibers themselves. Extreme neural fatigue can be experienced as temporary muscle failure. Some weight training programs, such as Metabolic Resistance Training, actively seek temporary muscle failure; evidence to support this type of training is mixed at best. Irrespective of their program, however, most athletes engaged in high-intensity weight training will experience muscle failure during their regimens.
There are many potential reasons, but I am going to keep it simple and give you just two. The first and most common reason people suffer from underactive glutes or “glute amnesia” is due to lifestyle. Even when people train hard every day, if they spend the majority of the remainder of the day sitting down, then they are simply not using their glutes. And remember the old saying - if you don’t use it, you lose it. Unfortunately, this is just what happens with your glutes.
Creatine is a naturally occurring compound found in muscle in large amounts. Creatine monohydrate is the supplement form and combines is a combination of the amino acids arginine, glycine, and methionine. Creatine drives the important creatine phosphate energy pathway, which is important in high-intensity activity such as weightlifting. Creatine can improve body bulk and training performance in high-intensity activities. Be aware that not everyone responds to creatine supplementation and 30 percent of users may not see any improvement. Women may not benefit as much as men. In weight training, increased strength, bulk, and fat loss are reasonably consistent results.
If you’re looking to put on extra muscle mass and build strength, there are a few things that need to occur. The first of these, even though it may seem obvious, is that you will need to have an exercise routine. To stimulate maximum muscle growth, you’ll need to challenge yourself in the gym, forcing your muscles to adapt to heavier workloads by increasing in size and strength.
Now that you've got the training part down, it's time to stretch it out. (Can you say ahhh?) Stretching while your muscles are warm can help improve your flexibility, says Davis, not to mention it just feels phenomenal after you've pushed yourself hard. A light cool-down is also great for calming the nervous system. While dynamic stretches should be your go-to during a warm-up, the cool-down is where static stretching comes in—this means holding a stretch for 20-30 seconds. These four passive stretches will do nicely.
Second, strength training has a much greater level of excess post-exercise oxygen consumption than aerobic exercise. What does this mean? When you finish a workout, your body needs to do a lot of work to replenish itself in order to bring itself back to a normal state (the way it was before you worked out). This takes a lot of energy, and some studies have shown that it can boost your metabolism for up to 38 hours after you finish your workout.
Creatine concentration is normally increased in the placenta and brain in the midgestation phase until term, with further increases in the brain for another two weeks after birth. This effect appears to be due to the fetus itself expressing the creatine enzymes of synthesis (AGAT and GAMT) after 5% of the gestation time has passed (0.9 days in spiny mice). Despite creatine normally suppressing AGAT when supplemented at high concentrations, it appears that maternal supplementation of the diet with 5% creatine from the halfway point of pregnancy until term does not alter creatine synthesis in the newborn (no alterations in either AGAT or GAMT), nor does it affect the creatine transporter.
Expert tip: To make it harder, inch yourself close to a wall so your trunk is about a foot away. Bring what would be your “planted” leg on the wall, foot flat against the surface. From here, raise your “non-working leg” up into the air, keeping your knee bent. As you raise up into the glute bridge, you’ll drive your heel against the wall, raising your hips. You can also use a bench. And like the standard bridge, you can up the ante by adding weight.
While some supplements may in fact provide health benefits, generally speaking, consumers should purchase and use these products cautiously as they are not closely regulated by the Food and Drug Administration (FDA). Also, bodybuilders are advised to discuss supplementation plans with a registered dietitian or primary care physician prior to use to optimize effectiveness and minimize potential harmful consequences.
Testosterone is significantly correlated with aggression and competitive behaviour and is directly facilitated by the latter. There are two theories on the role of testosterone in aggression and competition. The first one is the challenge hypothesis which states that testosterone would increase during puberty thus facilitating reproductive and competitive behaviour which would include aggression. Thus it is the challenge of competition among males of the species that facilitates aggression and violence. Studies conducted have found direct correlation between testosterone and dominance especially among the most violent criminals in prison who had the highest testosterone levels. The same research also found fathers (those outside competitive environments) had the lowest testosterone levels compared to other males.
You can't scroll through Instagram without clocking a mammoth cheat day feast, but are real-life bodybuilders consuming such a crazy amount of calories every couple of weeks? Not quite. When he’s dieting for a competition, Terry incorporates ‘re-feed days’ into his schedule. This means he eats the exact same food, but essentially doubles the portion sizes.