^ Jump up to: a b c d e f g h Momaya A, Fawal M, Estes R (April 2015). "Performance-enhancing substances in sports: a review of the literature". Sports Med. 45 (4): 517–531. doi:10.1007/s40279-015-0308-9. PMID 25663250. Wilson et al. [91] demonstrated that when non-resistance trained males received HMB pre-exercise, the rise of lactate dehydrogenase (LDH) levels reduced, and HMB tended to decrease soreness. Knitter et al. [92] showed a decrease in LDH and creatine phosphokinase (CPK), a byproduct of muscle breakdown, by HMB after a prolonged run. ... The utility of HMB does seem to be affected by timing of intake prior to workouts and dosage [97].
Spero Karas, MD, assistant professor of orthopaedics in the division of sports medicine at Emory University, says that testosterone, the male hormone responsible for muscle growth, maxes out between the ages of 16 and 18. It reaches a plateau during the 20s and then begins to decline. As a result, muscle building after the adolescent years can be challenging, he says.

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 »
MET-Rx Advanced Creatine Blast also contains a lot of ingredients that work synergistically with creatine. There’s the 33 grams of carbohydrates, which may help to drive creatine to the muscles, plus there’s some taurine to help with recovery and two grams of branched chain amino acids, which may help with muscle retention. However, it contains creatine ethyl ester, which is probably less effective than monohydrate.
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]
Eat healthy fats. That's right—not only does it make food taste good, fat is good for you, as long as you are eating the right kinds and amounts of fat! Saturated fats—the fat you'll find in a stick of butter, a bag of chips, or bacon—should be limited to about 20g or less. That's the bad news. The good news is that unsaturated fats are actually beneficial, even necessary. Fat is necessary for the proper distribution of vitamins A, D, E, and K, helps promote better eyesight, and healthy skin. Fats are also important for the synthesis of hormones, so maintaining an adequate intake of them will speed up muscle-building and recovery.
Creatine pyruvate (also known as creatine 2-oxopropanoate) in an isomolar dose relative to creatine monohydrate has been shown to produce higher plasma levels of creatine (peak and AUC) with no discernible differences in absorption or excretion values.[83] The same study noted increased performance from creatine pyruvate at low (4.4g creatine equivalence) doses relative to citrate and monohydrate, possibly due to the pyruvate group.
The 1960s saw the gradual introduction of exercise machines into the still-rare strength training gyms of the time. Weight training became increasingly popular in the 1970s, following the release of the bodybuilding movie Pumping Iron, and the subsequent popularity of Arnold Schwarzenegger. Since the late 1990s increasing numbers of women have taken up weight training, influenced by programs like Body for Life; currently nearly one in five U.S. women engage in weight training on a regular basis.[4]
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.
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.[104][105] When fed to chickens, phosphorylated cyclocreatine can accumulate up to 60mM in skeletal muscle,[106] which suggests a sequestering of phosphate groups before equilibrium is reached.[105] 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.[102] 

That said, many people experience stomach cramps when they consume creatine monohydrate and it’s possible that taking a creatine with a different pH — usually creatine hydrochloride — can have a different effect on stomach acid and make for a creatine that digests more easily. As far as we know, the easier digestion doesn’t necessarily mean it’s more effective or that you need less of it to achieve the desired result.
Using clinically effective doses of potent ingredients, Transparent Labs' StrengthSeries Creatine HMB combines creatine monohydrate with HMB in order to boost strength, lengthen endurance, and reduce fat. Along with the addition of BioPerine, StrengthSeries Creatine HMB is able to increase the rate of absorption and dispersion of this powerful creatine formula. Each serving of Creatine HMB contains 5g of Creatine, 2 g of HMB, and 5mg of BioPerine! Keep Reading »

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.
Creatine is an organic acid naturally occurring in the body that supplies energy to muscle cells for short bursts of energy (as required in lifting weights) via creatine phosphate replenishment of ATP. A number of scientific studies have shown that creatine can improve strength,[32] energy,[33] muscle mass, and recovery times. In addition, recent studies have also shown that creatine improves brain function.[34] and reduces mental fatigue.[35] Unlike steroids or other performance-enhancing drugs, creatine can be found naturally in many common foods such as herring, tuna, salmon, and beef.
Still, it's important to realize that for everyone, at a certain point, building muscle becomes more difficult. "We all have an endpoint to our genetic potential," Matheny says. "Someone who is starting strength training for the first time can build muscle with a lower percentage of their 1RM [the maximum amount of weight they can lift one time] than a more tenured athlete. The longer you train and the closer you to get to your natural potential, the more specific you need to get with your training and nutrition to keep making progress. And that week-by-week progress will likely be much smaller than it once was."
Now, while all three are definitely beneficial to the process, I’d consider metabolic stress and muscular damage to be of secondary and tertiary importance, respectively. In addition, they are also things that will pretty much take care of themselves when implementing the workout guidelines and recommendations we’ve already covered (namely for volume, rep ranges, rest periods and exercise selection).
Unfortunately, some people are intolerant to milk, due to the casein (one of the proteins in dairy) and have trouble digesting the sugar in milk, called lactose. If this is the case, stick to whey-only protein shakes. Maximuscle uses Biomax Whey True Protein - a unique blend of whey proteins including whey protein concentrate, isolate and hydrolysate, which are lower in lactose. Biomax Whey True Protein is used in a number of Maximuscle products (Promax and Cyclone).
The synthesis of creatine (from guanidinoacetate via GAMT) also requires SAMe as a cofactor and is implicated in homocysteine production. While supplementation of guanidinoacetate at 0.36% (prior to SAMe) can increase homocysteine by up to 50% in rats, supplementation of creatine (0.4%) is able to suppress homocysteine by up to 25%, secondary to reducing creatine synthesis,[309] and has been replicated elsewhere with 2% of the rat diet, while a loading phase did not alter the benefits.[124]
It is equally important, if not more so, to ensure that you supply your body with more protein than it is breaking down each day. Your body uses protein for many things daily, and when you are working out, your body may start to break down proteins to provide extra energy. But your body also requires proteins to create new muscle cells and repair damaged ones. Many bodybuilding supplements contain large amounts of protein to ensure that your body has plenty for all required processes. Jump to Our 10 Best Bodybuilding Supplement List
The last survivors of the pro-hormone supplements, which were removed from sale last January, estrogen-blocking supplements aren't pro-hormones but do inhibit the enzyme aromatase, which converts androgens into estrogens. In normal men that enzyme is ubiquitous, being present in such tissues as muscle, brain and skin. About 20 percent of the free testosterone circulating in the blood is converted into estrogen by way of aromatase.
Need the motivation to push past your comfort zone and squeeze out one more push-up or bicep curl? Sure, it helps to remember that you’ll get stronger, rock more toned muscles and rev your metabolism, thanks to all that added muscle mass. But if that wasn’t enough, now comes news that all that pump-itude (yes, that’s an SNL reference) has psychological benefits, too.
Heath is an unlikely Mr. Olympia. He grew up on playgrounds in Seattle playing basketball. His backcourt mate on the 1998 state championship team at Rainier Beach High School was Jamal Crawford, still in the N.B.A. Heath, just 5 feet 9 inches and a naturally chiseled 175 pounds, got a Division I basketball scholarship at the University of Denver. He majored in business and averaged 1.3 points over four seasons.
Even if your focus is on a particular body part, say getting flat abs or losing fat around the hips, it's important to work all your muscle groups. Spot reduction doesn't work, so doing crunches for your abs or leg lifts for your thighs isn't going to help you achieve your goal. What does work is building more lean muscle tissue and burning more calories.
Always consult your doctor before you begin taking a creatine supplement to make sure that there are no negative interactions with whatever diabetes medication you are on. If they deem you to be safe to take creatine, we recommend this unflavored powder from MET-Rx. It’s made without artificial sweeteners, flavors, and colors, so it's just pure creatine monohydrate powder to promote increased muscle strength. One reviewer noted the product is easy to mix and another said the formula was effect for their needs.
1. Train each muscle group twice per week. To maximize muscle growth, plan to train every major muscle group at least twice per week. According to a 2016 Sports Medicine review, even if you don't work that muscle any harder or longer, by simply dividing your chest, leg or back workout into two days, you'll spur more muscle growth. While the jury is still out on whether training each muscle group three days per week is better than two at spurring hypertrophy, it is likely better suited toward experienced lifters than beginners, Matheny says.
The materials and information provided in this presentation, document and/or any other communication (“Communication”) from Onnit Labs, Inc. or any related entity or person (collectively “Onnit”) are strictly for informational purposes only and are not intended for use as diagnosis, prevention or treatment of a health problem or as a substitute for consulting a qualified medical professional. Some of the concepts presented herein may be theoretical.
Longer rest periods are more ideal for making progressive tension overload happen, and shorter rest periods are more ideal for generating metabolic fatigue. So, if you’re doing an exercise that is better suited for progressive overload (i.e. primary compound exercises), you’re going to want to rest longer between sets to maximize strength output. And if you’re doing an exercise that is better suited for metabolic fatigue (i.e. isolation exercises), you’re going to want to rest less between sets to make that happen. And if you’re doing an exercise that is suited equally for a combination of the two (i.e. secondary compound exercises), you’re usually going to want a moderate rest period somewhere in between.
In otherwise healthy adults subject to leg immobilization for two weeks while taking 20g creatine daily during immobilization and then 5g daily during eight weeks of rehabilitation, it was noted that the creatine group failed to reduce atrophy during the immobilization (10% reduction in cross sectional area and 22-25% reduction in force output) despite preventing a decrease in phosphocreatine, yet experienced a significantly enhanced rate of regrowth and power recovery.[358] A similarly structured and dosed study has also noted greater expression of skeletal muscle, GLUT4 expression, and a 12% increase in muscle phosphocreatine content.[330]
Build an effective exercise routine. A good diet is required for your body to be able to maximize your potential, but there's no potential at all until you start the process of tearing down your old muscles and rebuilding them bigger, bulkier, and stronger. The best way to do that is to start at the beginning. If you're not sure where to begin, find a solid workout program online and try it out for a while. Don't immediately jump from one program to the next - you'll end up keeping yourself from making steady progress.

Take time to rest. To give your muscles time to recover, rest one full day between exercising each specific muscle group. You might choose to work the major muscle groups at a single session two or three times a week, or plan daily sessions for specific muscle groups. For example, on Monday work your arms and shoulders, on Tuesday work your legs, and so on.


Many non-competitive bodybuilders choose not to adopt this conventional strategy, as it often results in significant unwanted fat gain during the "bulking" phase. The attempt to increase muscle mass in one's body without any gain in fat is called clean bulking. Competitive bodybuilders focus their efforts to achieve a peak appearance during a brief "competition season".[citation needed] Clean bulking takes longer and is a more refined approach to achieving the body fat and muscle mass percentage a person is looking for. A common tactic for keeping fat low and muscle mass high would be to have higher calorie and lower calorie days to maintain a balance between gain and loss. Many clean bulk diets start off with a moderate amount of carbs, moderate amount of protein, and a decently low amount of fats. "Gaining lean muscle means going for leaner cuts of meat, like flank steaks and fillets, chicken, and, of course, fish," says White[who?]. "Enjoy your meat with some starch: rice, beans, quinoa, whole-grain couscous, or sweet potato, for example".[20] To maintain a clean bulk it is important to reach calorie goals every day. Macronutrient goals will be different for each person, but, it is ideal to get as close as possible.

Chwalbinska-Monteta [34] observed a significant decrease in blood lactate accumulation when exercising at lower intensities as well as an increase in lactate threshold in elite male endurance rowers after consuming a short loading (5 days 20 g/d) CM protocol. However, the effects of creatine supplementation on endurance performance have been questioned by some studies. Graef et al [35] examined the effects of four weeks of creatine citrate supplementation and high-intensity interval training on cardio respiratory fitness. A greater increase of the ventilatory threshold was observed in the creatine group respect to placebo; however, oxygen consumption showed no significant differences between the groups. The total work presented no interaction and no main effect for time for any of the groups. Thompson et al [36] reported no effects of a 6 week 2 g CM/d in aerobic and anaerobic endurance performance in female swimmers. In addition, of the concern related to the dosage used in these studies, it could be possible that the potential benefits of creatine supplementation on endurance performance were more related to effects of anaerobic threshold localization.
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.

Weight training has also been shown to benefit dieters as it inhibits lean body mass loss (as opposed to fat loss) when under a caloric deficit. Weight training also strengthens bones, helping to prevent bone loss and osteoporosis. By increasing muscular strength and improving balance, weight training can also reduce falls by elderly persons. Weight training is also attracting attention for the benefits it can have on the brain, and in older adults, a 2017 meta analysis found that it was effective in improving cognitive performance.[38]


Fast twitch (or Type II fibers) fire very quickly, but also fatigue quickly, so they don’t last long.  It gets a bit more complicated, because there are actually two types of fast twitch fibers. Type IIA fibers have some endurance qualities (used for things such as longer sprints). While Type IIX fibers are our “super fast” fibers, used only when a super short burst is needed (like a 100 m sprint or a really heavy lift).
Take time to rest. To give your muscles time to recover, rest one full day between exercising each specific muscle group. You might choose to work the major muscle groups at a single session two or three times a week, or plan daily sessions for specific muscle groups. For example, on Monday work your arms and shoulders, on Tuesday work your legs, and so on.
Bodybuilders have THE BEST mind to muscle connection of any resistance-training athletes. Ask a seasoned bodybuilder to flex their lats or their rhomboids or their hamstrings and they will do it with ease. Ask other strength athletes and you will see them struggle and although they may tense up the target muscle they will also tense up about 15 other surrounding muscles. This is because strength athletes train MOVEMENTS. They don’t care about targeting their lats. They just want to do the most pull ups. They don’t worry about feeling their quads. They just want to squat maximum weight. Although this is an expected and positive thing for the most part, there are real benefits to being able to isolate and target muscles.
The type of exercise performed also depends on the individual's goals. Those who seek to increase their performance in sports would focus mostly on compound exercises, with isolation exercises being used to strengthen just those muscles that are holding the athlete back. Similarly, a powerlifter would focus on the specific compound exercises that are performed at powerlifting competitions. However, those who seek to improve the look of their body without necessarily maximizing their strength gains (including bodybuilders) would put more of an emphasis on isolation exercises. Both types of athletes, however, generally make use of both compound and isolation exercises.
Why less volume for the smaller muscle groups, you ask? Partially because they are smaller, but mostly because they get a ton of indirect volume while training the bigger muscle groups (e.g. your biceps get hit pretty hard while training back, triceps get hit pretty hard while training chest and shoulders, shoulders get hit pretty hard while training chest, etc.).
Note that this recommendation is for total weekly volume, which means it would need to be divided up based on how many times you’re training each muscle group per week. So, for example, someone training everything twice per week would do 30-70 reps for each bigger muscle group in each of those workouts, and 15-35 reps for each smaller muscle group in each of those workouts.

A thermogenic is a broad term for any supplement that the manufacturer claims will cause thermogenesis, resulting in increased body temperature, increased metabolic rate, and consequently an increased rate in the burning of body fat and weight loss. Until 2004 almost every product found in this supplement category comprised the "ECA stack": ephedrine, caffeine and aspirin. However, on February 6, 2004 the Food and Drug Administration (FDA) banned the sale of ephedra and its alkaloid, ephedrine, for use in weight loss formulas. Several manufacturers replaced the ephedra component of the "ECA" stack with bitter orange or citrus aurantium (containing synephrine) instead of the ephedrine.

Ancient Greek sculptures also depict lifting feats. The weights were generally stones, but later gave way to dumbbells. The dumbbell was joined by the barbell in the later half of the 19th century. Early barbells had hollow globes that could be filled with sand or lead shot, but by the end of the century these were replaced by the plate-loading barbell commonly used today.[3]
Nutricost's BCAA packs a powerful punch when it comes to quality for the price. With 6 grams of L-Leucine, L-Isoleucine, and L-Valine in every serving, and 83 servings per bottle, each scoop equates to just 23 cents. These high quality branched chain amino acids help support protein synthesis, muscle recovery, while boosting endurance and stamina. This straight forward formula is free of calories and comes in several natural, easily mixed fruit flavors. Keep Reading »

As scientific research progressed, it became apparent that the best types of protein came from milk and eggs. That led to the next great revolution in sports nutrition, namely the engineered food, pioneered by Scott Connelly, M.D., a critical care specialist from Northern California who teamed with a young entrepreneur named Bill Phillips from Golden, Colorado.
You are eligible for a full refund if no ShippingPass-eligible orders have been placed. You cannot receive a refund if you have placed a ShippingPass-eligible order. In this case, the Customer Care team will remove your account from auto-renewal to ensure you are not charged for an additional year and you can continue to use the subscription until the end of your subscription term.
^ Jump up to: a b c d e Cooper R, Naclerio F, Allgrove J, Jimenez A (July 2012). "Creatine supplementation with specific view to exercise/sports performance: an update". Journal of the International Society of Sports Nutrition. 9 (1): 33. doi:10.1186/1550-2783-9-33. PMC 3407788. PMID 22817979. Creatine is produced endogenously at an amount of about 1 g/d. Synthesis predominately occurs in the liver, kidneys, and to a lesser extent in the pancreas. The remainder of the creatine available to the body is obtained through the diet at about 1 g/d for an omnivorous diet. 95% of the bodies creatine stores are found in the skeletal muscle and the remaining 5% is distributed in the brain, liver, kidney, and testes [1].

Each serving of Optimum Nutrition Creatine supplies a full 5 grams (5000 mg) of 99.9% pure Creapure brand Creatine Monohydrate. The patented production method used to produce this Creatine yields a tasteless, odorless powder that mixes easily into water or juice and does not readily settle to the bottom. As a result, the gritty taste or texture you may have experienced with other Creatine powders is not associated with this product. Keep Reading »


Bird, L. M., Tan, W. H., Bacino, C. A., Peters, S. U., Skinner, S. A., Anselm, I., Barbieri-Welge, R., Bauer-Carlin, A., Gentile, J. K., Glaze, D. G., Horowitz, L. T., Mohan, K. N., Nespeca, M. P., Sahoo, T., Sarco, D., Waisbren, S. E., and Beaudet, A. L. A therapeutic trial of pro-methylation dietary supplements in Angelman syndrome. Am J Med Genet.A 2011;155A:2956-2963. View abstract.
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.

Fast twitch (or Type II fibers) fire very quickly, but also fatigue quickly, so they don’t last long.  It gets a bit more complicated, because there are actually two types of fast twitch fibers. Type IIA fibers have some endurance qualities (used for things such as longer sprints). While Type IIX fibers are our “super fast” fibers, used only when a super short burst is needed (like a 100 m sprint or a really heavy lift).
If you’re a beginner, you should train with three full-body workouts per week. In each one, do a compound pushing movement (like a bench press), a compound pulling movement (like a chinup), and a compound lower-body exercise (squat, trap-bar deadlift, for example). If you want to add in 1–2 other exercises like loaded carries or kettlebell swings as a finisher, that’s fine, but three exercises is enough to work the whole body.
Having a spotter nearby is particularly important when using free weights. Even someone in great shape sometimes just can't make that last rep. It's no big deal if you're doing biceps curls; all you'll have to do is drop the weight onto the floor. But if you're in the middle of a bench press — a chest exercise where you're lying on a bench and pushing a loaded barbell away from your chest — it's easy to get hurt if you drop the weight. A spotter can keep you from dropping the barbell onto your chest.
Gordon, P. H., Cheung, Y. K., Levin, B., Andrews, H., Doorish, C., Macarthur, R. B., Montes, J., Bednarz, K., Florence, J., Rowin, J., Boylan, K., Mozaffar, T., Tandan, R., Mitsumoto, H., Kelvin, E. A., Chapin, J., Bedlack, R., Rivner, M., McCluskey, L. F., Pestronk, A., Graves, M., Sorenson, E. J., Barohn, R. J., Belsh, J. M., Lou, J. S., Levine, T., Saperstein, D., Miller, R. G., and Scelsa, S. N. A novel, efficient, randomized selection trial comparing combinations of drug therapy for ALS. Amyotroph.Lateral.Scler. 2008;9(4):212-222. View abstract.

That means it's an important part of your overall fitness and it benefits people of all ages, plus it may be particularly important for people with health issues such as obesity, arthritis, or a heart condition. The Centers for Disease Control Prevention physical activity guidelines recommend that adults do muscle-strengthening activities on at least two or more days each week (targeting the legs, hips, back, abdomen, chest, shoulders, and arms). (2)
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.

One supplement, which a large body of research has proven effective in building muscle mass when combined with intensive strength training, is creatine (sold as creatine monohydrate). Creatine, a source of rapid energy, is stored in the muscles in small amounts. With creatine loading or supplementation, bodybuilders increase muscle stores of the energy-containing compound which then can be used to provide an extra boost for an intense-high-weight lifting session. Studies support that ingestion of a relatively high dose of creatine (20 to 30 grams per day for up to two weeks) increases muscle creatine stores by 10 to 30 percent and can boost muscle strength by about 10 percent when compared with resistance training alone (Rawson & Volek, 2003). Some athletes report (though research does not necessarily support) muscle cramping in response after using creatine supplements.


It is known that intracellular energy depletion (assessed by a depletion of ATP) stimulates AMPK activity in order to normalize the AMP:ATP ratio,[333][334] and when activated AMPK (active in states of low cellular energy[335] and colocalizes with creatine kinase in muscle tissue[336]) appears to inhibit creatine kinase via phosphorylation (preserving phosphocreatine stores but attenuating the rate that creatine buffers ATP). While phosphocreatine technically inhibits AMPK, this does not occur in the presence of creatine at a 2:1 ratio.[334] It seems that if the ratio of phosphocreatine:creatine increases (indicative of excess cellular energy status) that AMPK activity is then attenuated, since when a cell is in a high energy status, there is less AMP to directly activate AMPK.[334][336][337]
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