2-[carbamimidoyl(methyl)amino]acetic acid, Cr, Creatin, Creatina, Créatine, Créatine Anhydre, Creatine Anhydrous, Creatine Citrate, Créatine Citrate, Creatine Ethyl Ester, Créatine Ethyl Ester, Creatine Ethyl Ester HCl, Créatine Ethyl Ester HCl, Creatine Gluconate, Creatine Hydrochloride, Créatine Kré Alkaline, Creatine Malate, Créatine Malate, Creatine Monohydrate, Créatine Monohydrate, Créatine Monohydratée, Creatine Pyroglutamate, Créatine Pyroglutamate, Creatine Pyruvate, Créatine Pyruvate, Dicreatine Malate, Dicréatine Malate, Di-Creatine Malate, Éthyle Ester de Créatine, Glycine, Kreatin, Kre-Alkalyn Pyruvate, Malate de Tricréatine, N-(aminoiminométhyl)-N-Méthyl, N-(aminoiminomethyl)-N methyl glycine, N-amidinosarcosine, Phosphocreatine, Phosphocréatine, Tricreatine HCA, Tricréatine HCA, Tricreatine Malate, Tricréatine Malate.
Peirano, R. I., Achterberg, V., Dusing, H. J., Akhiani, M., Koop, U., Jaspers, S., Kruger, A., Schwengler, H., Hamann, T., Wenck, H., Stab, F., Gallinat, S., and Blatt, T. Dermal penetration of creatine from a face-care formulation containing creatine, guarana and glycerol is linked to effective antiwrinkle and antisagging efficacy in male subjects. J.Cosmet.Dermatol. 2011;10(4):273-281. View abstract. 

In regard to the blood brain barrier (BBB), which is a tightly woven mesh of non-fenestrated microcapillary endothelial cells (MCECs) that prevents passive diffusion of many water-soluble or large compounds into the brain, creatine can be taken into the brain via the SLC6A8 transporter.[192] In contrast, the creatine precursor (guanidinoacetate, or GAA) only appears to enter this transporter during creatine deficiency.[192] More creatine is taken up than effluxed, and more GAA is effluxed rather than taken up, suggesting that creatine utilization in the brain from blood-borne sources[192] is the major source of neural creatine.[193][192] However, “capable of passage” differs from “unregulated passage” and creatine appears to have tightly regulated entry into the brain in vivo[193]. After injecting rats with a large dose of creatine, creatine levels increased and plateaued at 70uM above baseline levels. These baseline levels are about 10mM, so this equates to an 0.7% increase when superloaded.[193] These kinetics may be a reason for the relative lack of neural effects of creatine supplementation in creatine sufficient populations.


Transparent Labs' StrengthSeries Creatine HMB is an impressive blend that includes 5 grams of Creatine Monohydrate, 2 Grams Beta-Hydroxy Beta- Methylbutrate (HMB), and 5 mg of Black Pepper Extract for increased absorption. These clinically effective doses have been shown to enhance strength, boost muscle gains, and minimize fat and muscle loss. Made with no artificial sweeteners, coloring, or preservatives, each serving of is pure, unadulterated Creatine. Keep Reading »
Escolar, D. M., Buyse, G., Henricson, E., Leshner, R., Florence, J., Mayhew, J., Tesi-Rocha, C., Gorni, K., Pasquali, L., Patel, K. M., McCarter, R., Huang, J., Mayhew, T., Bertorini, T., Carlo, J., Connolly, A. M., Clemens, P. R., Goemans, N., Iannaccone, S. T., Igarashi, M., Nevo, Y., Pestronk, A., Subramony, S. H., Vedanarayanan, V. V., and Wessel, H. CINRG randomized controlled trial of creatine and glutamine in Duchenne muscular dystrophy. Ann Neurol 2005;58:151-155. View abstract.

Due to this relative deficiency-state in vegetarians and vegans, some aspects of creatine supplementation are seen as more akin to normalizing a deficiency, rather than providing the benefits of supplementation. In young vegetarians, but not omnivores, creatine supplementation can enhance cognition.[60][61] The increased gain in lean mass may be more significant in vegetarians, relative to omnivores.[59] Supplementation of creatine in vegetarians appears to normalize the gap in storage between vegetarians and omnivores.[62] This is possibly related to a correlation seen in survey research, where vegetarianism and veganism appear to be more commonly affected by some mental disorders like anxiety and depression.[63]
The pancreas is one of the extrahepatic (beyond the liver) organs that can synthesize creatine, alongside the kidneys.[486][487] Freshly prepared pancreatic β-cells will normally secrete insulin in response to glucose stimulation, and it appears that phosphocreatine is required for this effect, since phosphocreatine is increased in response to glucose[488] alongside an increase of the ADP:ATP ratio. They appear to close ATP sensitive potassium channels (KATP channels), causing a release of insulin secondary to calcium release.[488] Both phosphocreatine[488] and ADP[489] are implicated, but it seems that despite the channel being sensitive to ATP,[490] the concentration of ATP in a pancreatic cell (3-5mM[491][492]) is already above the activation threshold (in the micromolar range[493]) and thus a further increase would not have an appreciable effect.
Tribulus Terrestris: A fruit from the Mediterranean, this supplement has been used in the Indian traditional medicine of Ayurveda. In addition to helping increase testosterone, many people take it to increase libido and as a cardioprotective aid. (10) Unfortunately, despite the fact that there are claims that tribulus terrestris can increase testosterone levels, studies don’t back up these claims.  There is some evidence, however, that it may improve athletic performance. If you want to choose one of the supplements for men, this should be your pick.
A recent review article published in The American Journal of Clinical Nutrition highlighted the benefits of protein supplementation and showed that supplementing with protein during prolonged (greater than 6 weeks) resistance-type training can lead to significantly greater increases in muscle mass and strength when compared to resistance training without a dietary protein intervention.[15]

Carducci, C., Birarelli, M., Leuzzi, V., Carducci, C., Battini, R., Cioni, G., and Antonozzi, I. Guanidinoacetate and creatine plus creatinine assessment in physiologic fluids: an effective diagnostic tool for the biochemical diagnosis of arginine:glycine amidinotransferase and guanidinoacetate methyltransferase deficiencies. Clin Chem 2002;48(10):1772-1778. View abstract.
Wilkinson, S. B., Tarnopolsky, M. A., MacDonald, M. J., MacDonald, J. R., Armstrong, D., & Phillips, S. M. (2007). Consumption of fluid skim milk promotes greater muscle protein accretion after resistance exercise than does consumption of an isonitrogenous and isoenergetic soy-protein beverage. The American Journal of Clinical Nutrition, 85(4), 1031-1040.
The reasons for differences in the effect of creatine on testosterone vs. DHT across studies are not clear, but also not mutually exclusive. A measured increase in DHT could indicate that testosterone levels were increased by creatine, but rapidly converted to DHT through a homeostatic mechanism. Differences in study subject populations, methodology, or the presence and type of concurrent exercise could also be contributing factors. At any rate, the literature collectively suggests that creatine has the general ability to cause a modest increase in androgen levels in men.
Many trainees like to cycle between the two methods in order to prevent the body from adapting (maintaining a progressive overload), possibly emphasizing whichever method more suits their goals; typically, a bodybuilder will aim at sarcoplasmic hypertrophy most of the time but may change to a myofibrillar hypertrophy kind of training temporarily in order to move past a plateau. However, no real evidence has been provided to show that trainees ever reach this plateau, and rather was more of a hype created from "muscular confusion".[clarification needed][citation needed]
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.[6]
Once training is resumed under these conditions, there may be little in the way of caloric support to ensure that protein synthesis and muscle growth occurs. Muscle may even begin to cannibalize itself as the body enters into a catabolic state. Even with the best of diets this can sometimes happen if training demands override the nutritional balance or imbalance.
Consuming sufficient high-quality protein is essential for building muscle. Current recommendations are to consume a minimum of 0.8g of protein for each kg of body weight, however, this is really only applicable to the average sedentary individual. Current evidence shows that to support muscle development, protein intake is the key, therefore the recommended 0.8g per kg should be increased to 1.5-2.0g of protein per kg of body weight. For an 80 kg individual, that would equate to 120-160 grams of protein per day.
It’s true—your genes can play a role when it comes to building muscle. In general, there are two types of muscle fibers: Type I, which are slow twitch, and Type II, which are fast twitch. Depending on which you have more of, you may have an easier or harder time gaining muscle. “Fast twitch muscle fibers are two times as thick as slow twitch muscle fibers, lending to the overall thickness of the muscle without any activity,” explains Lovitt. “Those people with a genetic predisposition of a high percentage of these fibers can increase muscle size very easily while the people with a higher percentage of slow twitch muscle fibers have to work really hard to put on mass.” It’s the reason why a world-class sprinter genetically has more fast twitch muscle fibers than a world-class marathoner—it comes down to what we’re born with.
“I would really focus on learning how macros work, how your body works and how it reacts to certain foods, and what your body requires each day to maintain your weight,” he advises. “Then you can start playing around with increasing calories [to bulk up], and decreasing calories when you're dieting.” Our beginner's guide to macros will definitely help.

Free weights include dumbbells, barbells, medicine balls, sandbells, and kettlebells. Unlike weight machines, they do not constrain users to specific, fixed movements, and therefore require more effort from the individual's stabilizer muscles. It is often argued that free weight exercises are superior for precisely this reason. For example, they are recommended for golf players, since golf is a unilateral exercise that can break body balances, requiring exercises to keep the balance in muscles.[27]
Phosphocreatine is known to be a major source of energy for cardiac tissue alongside fatty acids, which are dominant under periods of normoxia (normal oxygen) while phosphocreatine becomes more important in periods of hypoxic stress.[281][282][283] The entire CK system plays a role in the recovery of the heart following ischemic/hypoxic stress, since blocking CK activity impairs recovery[284][285] and overexpressing CK activity promotes it.[286] This is due to the heart tissue needing high energy phosphate groups at this time, and the ischemic stress reduces CK activity and the ability of CK to donate these groups.[287][288]

Change things up. After six or more weeks of consistent strength training, which is about the amount of time it takes to start seeing improvement in your body, you can change your routine to make it more difficult. Lifting the same weights for the same exercises every week will keep your body in the same place. You can modify weights or repetitions, choose different exercises, or change the order in which you do them. You only have to make one change at a time to make a difference, although more is often better. 
For several years, research studies have shown that adolescents concerned with both athletics and appearance are taking performance-enhancing supplements. A study by the American Academy of Pediatrics of middle-school and high-school students ages 10 to 18 years found creatine use in all grades 6 through 12. About 5.6% of the study participants and 44% of high-school senior athletes admitted taking creatine.

THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional medical advice, diagnosis or treatment and should not be relied on to make decisions about your health. Never ignore professional medical advice in seeking treatment because of something you have read on the WebMD Site. If you think you may have a medical emergency, immediately call your doctor or dial 911.


Kerksick, C. M., Wilborn, C. D., Campbell, W. I., Harvey, T. M., Marcello, B. M., Roberts, M. D., Parker, A. G., Byars, A. G., Greenwood, L. D., Almada, A. L., Kreider, R. B., and Greenwood, M. The effects of creatine monohydrate supplementation with and without D-pinitol on resistance training adaptations. J.Strength.Cond.Res. 2009;23:2673-2682. View abstract.
There's good news, though: These temporary muscle pumps are critical to improving muscle hypertrophy, or muscle growth, according to 2014 research in the Strength and Conditioning Journal. So you can think of your weight-room pump as a preview of the muscle results that are to come. Speaking of which, here's an expert-endorsed timeline to reach your muscle-building goals.
Sandow was so successful at flexing and posing his physique that he later created several businesses around his fame, and was among the first to market products branded with his name. He was credited with inventing and selling the first exercise equipment for the masses: machined dumbbells, spring pulleys, and tension bands. Even his image was sold by the thousands in "cabinet cards" and other prints. Sandow was a perfect "Gracilian", a standard of ideal body proportions close to those of ancient Greek and Roman statues. Men's physiques were then judged by how closely they matched these proportions.

Creatine is known to be present in the retina due to the expression of creatine kinase (CK)[466][39] and the GAMT enzyme of creatine synthesis, which is also present in the mammalian retina.[467] Creatine in the blood can be transported into the retina via the creatine transporter (confirmed in humans[468]), and inhibiting transporter activity (by depleting the medium of chloride and sodium) reduces uptake by 80%.[469] The fact that not all uptake was inhibited suggests that another transporter, such as the monocarboxylate transporter MCT12 (or SLC16A12),[470] plays a role, perhaps moreso in the lens, where its levels were comparable to that of the major creatine transporter SLC6A8.[470] 


A: At the end of the day, the most important variable regarding weight gain or loss is calorie consumption. However, meal frequency and timing around activity can both influence workout intensity and duration thus potentially allowing for further improvements in body composition. Remember, muscle growth isn’t a pulsatile process, it doesn’t just acutely spike and then return to baseline so if there aren’t circulating amino acids within the blood stream then they’ll have to be broken down from muscle as this is the highest form of concentrated amino acids within the body. That being said, it would probably be a good idea to consume anywhere from 3-6 meals spread throughout the day depending upon your schedule and preference. Ideally, we want to stimulate anabolism through food every 3-5 hours.


While it'’s okay to chow down on the occasional fast-food choice for convenience, a mass-gain program isn'’t an excuse to gorge on pizza and chocolate sundaes. “"Rebuilding muscle tissue broken down by training requires energy -— in other words, calories,"” says bodybuilding nutritional guru Chris Aceto. "“But many people, including many nutritionists, overestimate the energy needs for gaining mass, encouraging extreme high-calorie intakes. This often leads to an increase in bodyfat, making you bigger, for sure, but also leaving you fat." In general, aim for 300-500 more calories every day than your body burns through exercise and normal functioning (multiply bodyweight by 17). And that'’s divided among six meals a day.
In the last week leading up to a contest, bodybuilders usually decrease their consumption of water, sodium, and carbohydrates, the former two to alter how water is retained by the body and the latter to reduce glycogen in the muscle. The day before the show, water is removed from the diet, and diuretics may be introduced, while carbohydrate loading is undertaken to increase the size of the muscles through replenishment of their glycogen. The goal is to maximize leanness and increase the visibility of veins, or "vascularity". The muscular definition and vascularity are further enhanced immediately before appearing on stage by darkening the skin through tanning products and applying oils to the skin to increase shine. Some competitors will eat sugar-rich foods to increase the visibility of their veins. A final step, called "pumping", consists in performing exercises with light weights or other kinds of low resistance (for instance two athletes can "pump" each other by holding a towel and pulling in turn), just before the contest, to fill the muscles with blood and further increase their size and density.
Maintaining proper form is one of the many steps in order to perfectly perform a certain technique. Correct form in weight training improves strength, muscle tone, and maintaining a healthy weight. Proper form will prevent any strains or fractures.[6] When the exercise becomes difficult towards the end of a set, there is a temptation to cheat, i.e., to use poor form to recruit other muscle groups to assist the effort. Avoid heavy weight and keep the number of repetitions to a minimum. This may shift the effort to weaker muscles that cannot handle the weight. For example, the squat and the deadlift are used to exercise the largest muscles in the body—the leg and buttock muscles—so they require substantial weight. Beginners are tempted to round their back while performing these exercises. The relaxation of the spinal erectors which allows the lower back to round can cause shearing in the vertebrae of the lumbar spine, potentially damaging the spinal discs.
But one question has repeatedly popped up: When is the best time to take creatine? Recent research has suggested that there might be an ideal time. That’s when I decided to speak with the supplement experts at Examine.com. For those of you who don’t know, they have created the world’s largest database of facts about supplements. No marketing BS. Just a bunch of Ph.D’s, PharmD’s, and biomedical researchers who are obsessed with sharing the truth. Their Supplement Guide is the best thing written about supplements since…well…ever. If you’ve ever had a question it’s pack with research and fact-based information to help you make healthier supplement choices.
Transparent Labs' StrengthSeries Creatine HMB is an impressive blend that includes 5 grams of Creatine Monohydrate, 2 Grams Beta-Hydroxy Beta- Methylbutrate (HMB), and 5 mg of Black Pepper Extract for increased absorption. These clinically effective doses have been shown to enhance strength, boost muscle gains, and minimize fat and muscle loss. Made with no artificial sweeteners, coloring, or preservatives, each serving of is pure, unadulterated Creatine. Keep Reading »
This suppression of creatine synthesis is thought to actually be beneficial, since creatine synthesis requires s-adenosyl methionine as a cofactor and may use up to 40-50% of SAMe for methylation[35][36][122] (initially thought to be above 70%, but this has since been re-evaluated[122]) though the expected preservation of SAMe may not occur with supplementation.[487] Reduced creatine synthesis, via preserving methyl groups and trimethylglycine (which would normally be used up to synthesize SAMe), is also thought to suppress homocysteine levels in serum,[37] but this may also not occur to a practical level following supplementation.[487]
I was building up, bulking, going after the mass, which to me meant 230 pounds of sheer body weight. At that time, I didn’t care about my waist or anything else that would give me a symmetrical look. I just wanted to build a gigantic 250-pound body by handling a lot of weight and blasting my muscles. My mind was into looking huge, into being awesome and powerful. I saw it working. My muscles began bursting out all over. And I knew I was on my way.”

I HATE that the resistance training community can be so tribal. I have been preaching to bodybuilders for years about the benefits of powerlifting, or Olympic lifting or kettlebells or even Crossfit style conditioning and many have been receptive. Learn from each other and achieve levels of fitness you simply could not have otherwise. Don’t brush off bodybuilding wisdom…it could be the missing factor in your program.


However, if you increase the demands you are placing on your body by increasing the weight being lifted, lifting the same weight for additional reps, or just doing something that increases the demands that your body needs to meet, then your body will have no other choice but to make the changes and improvements necessary for it to adapt to this environment and remain capable of performing these tasks.
Progression – Throughout the course of your lifting career you should consistently strive for progress both mentally and physically. Initially, you may find that you’re incessantly focused on nutrition and training but as you progress in both maturity and muscular development, you should be focused on improving the balance between lifting and your life. It’s never about having an all or nothing mindset, balance must be incorporated in all aspects but this takes times to develop and occurs with progression over time.
If you’re satisfied with your athletic performance but seriously want to bulk up, we recommend these creatine pill supplements from Crazy Muscle. They're made of a blend of three of the most effective types of creatine, Creatine Monohydrate, Creatine Alpha-ketoglutarate and Creatine Pyruvate, instead of just one type like other supplement brands. The formula also promises faster recovery times between workouts so you can push yourself harder even after a big workout the day before.
Small but significant is good. It’s especially helpful during short periods of extremely powerful physical activity, particularly if those short bursts of activity are repeated, as in weightlifting, sprinting or football, for example. The study also says that creatine supplementation is associated with enhanced strength gains in strength training programs, which could be related to the greater volume and intensity of training that you can achieve when you’re taking creatine supplements. Plus, according to the study, there’s no evidence of gastrointestinal, renal or muscle cramping complications – more good news.
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. 
Once training is resumed under these conditions, there may be little in the way of caloric support to ensure that protein synthesis and muscle growth occurs. Muscle may even begin to cannibalize itself as the body enters into a catabolic state. Even with the best of diets this can sometimes happen if training demands override the nutritional balance or imbalance.

How much weight? Start with a pair of light dumbbell hand weights (2 to 3 pounds for women and 5 to 8 pounds for men). If you can’t do 12 repetitions (or reps are the number of times you do the exercise) the weight is too heavy. If your muscles don’t feel tired after 12 reps, it’s too light. Adjustable weights that can be strapped to wrists or ankles may be convenient if you have arthritis in your hands. You can also use home or gym weight machines, or resistance bands.

The best way to know the real progress you’re making is by recording it on video or taking photos. “Photos mean everything because if you can take them in the same areas and in the same poses, you’ll see your strengths and weaknesses clearly,” says Heath. “Revise your training and diet programs to eliminate weaknesses.” Keep a file of your progress to see just how far you can take your fitness.
This is how the NPC differs from the NANBF. The NANBF takes a more direct approach by taking urine samples from all competitors that are tested for steroids and any other substances on the banned list. The NANBF also differs from the NPC when it comes to judging. The criteria for certain poses differs from organization to organization. The NANBF even has an elevated calf pose which is unique for their competitions.[citation needed]
Heath has 1.8 million Instagram followers, 300,000 Twitter followers, a global fan base and a growing portfolio of muscle magazine covers. He competes in just one competition a year, Mr. Olympia, for which he won the $400,000 first prize this year. He spends the rest of the year staying in shape and flying hundreds of thousands of miles for appearances, conferences and meetings. He has five sponsors, led by Ultimate Nutrition, a supplement company. All told, he earns more than $1 million a year, his agent said.
Ghost Size takes the cake for muscle growth. The key to this formula is epicatechin, an antioxidant found in chocolate and certain plants that is linked to a wide array of benefits. These include increased nitric oxide produciton, better oxygenation to the brain, and muscle growth: epicatechin appears to inhibit myostatin, which suppresses muscle growth, and the dosage found in Ghost Size is in line with studies that examined this effect.

Glycogen synthesis is known to respond directly and positively to cellular swelling. This was demonstrated in an earlier study, during which rat muscle cells were exposed to a hypotonic solution in vitro to induce cell swelling, which increased glycogen synthesis by 75%. In contrast, exposing these same cells to a hypertonic solution hindered glycogen synthesis by 31%. These changes were not due to alterations in glucose uptake, but are blocked by hindering the PI3K/mTOR signaling pathway.[112] It was later noted that stress proteins of the MAPK class (p38 and JNK) as well as heat shock protein 27 (Hsp27) are activated in response to increasing osmolarity.[113][114] Furthermore, activation of MAPK signaling in skeletal muscle cells is known to induce myocyte differentiation[115] via GSK3β and MEF2 signaling, which can induce muscle cell growth.[116][117]
Other supplements could easily have been included here, but these are considered the most useful and effective for the majority of bodybuilders and athletes. Although food should always come first, supplements offer an effective alternative for getting nutrients that either aren't available in sufficient quantity in food or are in foods that you may not be eating.
In regard to the blood brain barrier (BBB), which is a tightly woven mesh of non-fenestrated microcapillary endothelial cells (MCECs) that prevents passive diffusion of many water-soluble or large compounds into the brain, creatine can be taken into the brain via the SLC6A8 transporter.[192] In contrast, the creatine precursor (guanidinoacetate, or GAA) only appears to enter this transporter during creatine deficiency.[192] More creatine is taken up than effluxed, and more GAA is effluxed rather than taken up, suggesting that creatine utilization in the brain from blood-borne sources[192] is the major source of neural creatine.[193][192] However, “capable of passage” differs from “unregulated passage” and creatine appears to have tightly regulated entry into the brain in vivo[193]. After injecting rats with a large dose of creatine, creatine levels increased and plateaued at 70uM above baseline levels. These baseline levels are about 10mM, so this equates to an 0.7% increase when superloaded.[193] These kinetics may be a reason for the relative lack of neural effects of creatine supplementation in creatine sufficient populations.
The first open label trial on ALS failed to significantly alter lung function as assessed by FEV (when comparing the rate of decline pretreatment relative to treatment).[545] Creatine has elsewhere failed to benefit lung function at 5g daily for months relative to control[546] and failed to significantly attenuate the rate of lung function deterioration over 16 months at 10g daily[505] and 5g daily over nine months.[507]
It is prudent to note that creatine supplementation has been shown to reduce the body’s endogenous production of creatine, however levels return to normal after a brief period of time when supplementation ceases [1,6]. Despite this creatine supplementation has not been studied/supplemented with for a relatively long period. Due to this, long term effects are unknown, therefore safety cannot be guaranteed. Whilst the long term effects of creatine supplementation remain unclear, no definitive certainty of either a negative or a positive effect upon the body has been determined for many health professionals and national agencies [19,78]. For example the French Sanitary Agency has banned the buying of creatine due to the unproven allegation that a potential effect of creatine supplementation could be that of mutagenicity and carcinogenicity from the production of heterocyclic amines [78]. Long term and epidemiological data should continue to be produced and collected to determine the safety of creatine in all healthy individuals under all conditions [78].
Negative regulators of the creatine transporter (CrT) are those that, when activated, reduce the activity of the CrT and overall creatine uptake into cells. As noted above, CrT activity is positively regulated by mTOR.[158] Consistent with the well-known role of AMPK as a suppressor mTOR signaling,[177] CrT activity has also been shown to be inhibited in response to AMPK activation in kidney epithelial cells.[178] Since AMPK suppresses mTOR via upstream TSC2 activation,[179] the negative regulation of AMPK on CrT activity in these cells appears to occur through an indirect mechanism. Although indirect, activation of AMPK has been noted to reduce the Vmax of the CrT without altering creatine binding, and is involved in internalizing the receptors.[178] This pathway seems to max out at around 30% suppression, with no combination of mTOR antagonists and AMPK inducers further suppressing creatine uptake.[178]

Co-ingesting creatine with caffeine partially negated the benefits of creatine supplementation (at 5mg/kg bodyweight) during the loading phase in one study.[590] The exact mechanism responsible for this effect is not known, but might be related to opposing actions on muscle contraction time.[591] However, another study in trained men found that co-ingestion of 300mg caffeine per day during creatine loading at 20g per day (split into 4 doses) had no effect on bench press 1RM, time to fatigue, or sprinting ability.[592] However, this study also found that creatine alone or when combined with caffeine had no effect on any of these parameters over placebo, either. Thus, the study may have been underpowered or done in too short a time frame (the test was done after only 5 days of loading) to observe any possible effects.[592]

In addition to the basic principles of strength training, a further consideration added by weight training is the equipment used. Types of equipment include barbells, dumbbells, pulleys and stacks in the form of weight machines, and the body's own weight in the case of chin-ups and push-ups. Different types of weights will give different types of resistance, and often the same absolute weight can have different relative weights depending on the type of equipment used. For example, lifting 10 kilograms using a dumbbell sometimes requires more force than moving 10 kilograms on a weight stack if certain pulley arrangements are used. In other cases, the weight stack may require more force than the equivalent dumbbell weight due to additional torque or resistance in the machine. Additionally, although they may display the same weight stack, different machines may be heavier or lighter depending on the number of pulleys and their arrangements.

Safety. Excess quantities of antioxidants may produce a ‘pro-oxidant’ effect, which is the opposite of what you would take these supplements for. The Australian Institute of Sport recommends that antioxidant vitamin supplements only be taken for a period of a few weeks while the body adjusts to stressful circumstances. Excess vitamin C may promote excess iron absorption, which may not be healthy for everyone.
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