One study on 27 otherwise healthy men supplementing creatine (0.3g/kg loading for a week, 0.05g/kg thereafter for 8 weeks) with a thrice weekly exercise regiment noted that alongside greater increase in lean mass and power relative to placebo at 4 and 8 weeks, myostatin in serum decreased to a greater extent with creatine (around 17% at 8 weeks, derived from graph) than it did with placebo (approximately 7%). Increases in GASP-1, a serum protein that inhibits the actions of myostatin by directly binding to it, were not different between groups.
In regard to liver fat buildup (steatosis), which is normally associated with reduced availability of S-adenosyl methionine and a suppression in expression of genes involved in fatty acid oxidation (PPARα and CPT1), creatine supplementation at 1% of the rat diet alongside a diet that induces fatty liver is able to fully prevent (and nonsignificantly reduce relative to the control given standard diets) the aforementioned changes and the state of steatosis, as well as changes in serum biomarkers (glucose and insulin) that accompany steatosis.
Creatine monohydrate is the most common form of creatine, and if not otherwise mentioned is the default form of creatine used in most studies on creatine. It has fairly decent intestinal absorption (covered more in depth in the pharmacology section) and is the standard form or “reference” form of creatine, which all other variants are pitted against.
Gualano, B., de, Salles Painelli, V, Roschel, H., Lugaresi, R., Dorea, E., Artioli, G. G., Lima, F. R., da Silva, M. E., Cunha, M. R., Seguro, A. C., Shimizu, M. H., Otaduy, M. C., Sapienza, M. T., da Costa, Leite C., Bonfa, E., and Lancha Junior, A. H. Creatine supplementation does not impair kidney function in type 2 diabetic patients: a randomized, double-blind, placebo-controlled, clinical trial. Eur.J.Appl.Physiol 2011;111:749-756. View abstract.
Stronger muscles improve performance in a variety of sports. Sport-specific training routines are used by many competitors. These often specify that the speed of muscle contraction during weight training should be the same as that of the particular sport. Sport-specific training routines also often include variations to both free weight and machine movements that may not be common for traditional weightlifting.
You’ll Feel Better: Not only will you find yourself with more energy and confidence, less stress and anxiety, and a better overall mood, but you’ll actually begin to think better (resistance training has been proven to help increase cognitive function). And while training too close to bedtime can be a bad idea, exercising earlier in the day has been proven to help prevent sleep apnea and insomnia. I even improved my posture – when I started lifting, I was 5’4”. Now I’m 5’5.5”.
Beginners are advised to build up slowly to a weight training program. Untrained individuals may have some muscles that are comparatively stronger than others; nevertheless, an injury can result if (in a particular exercise) the primary muscle is stronger than its stabilizing muscles. Building up slowly allows muscles time to develop appropriate strengths relative to each other. This can also help to minimize delayed onset muscle soreness. A sudden start to an intense program can cause significant muscular soreness. Unexercised muscles contain cross-linkages that are torn during intense exercise. A regimen of flexibility exercises should be implemented before weight training begins, to help avoid soft tissue pain and injuries.
Genetic deficiencies in the creatine biosynthetic pathway lead to various severe neurological defects. Clinically, there are three distinct disorders of creatine metabolism. Deficiencies in the two synthesis enzymes can cause L-arginine:glycine amidinotransferase deficiency caused by variants in GATM and guanidinoacetate methyltransferase deficiency, caused by variants in GAMT. Both biosynthetic defects are inherited in an autosomal recessive manner. A third defect, creatine transporter defect, is caused by mutations in SLC6A8 and inherited in a X-linked manner. This condition is related to the transport of creatine into the brain.
Because so many product labels list scientific references to back up the manufacturers' claims of performance and efficacy, or effectiveness, it's important to understand what constitutes a solid scientific study. A single study, even an optimally designed one, isn't considered scientific proof. The results have to be replicated several times before they're officially accepted as fact.
ZMA: This supplement is a combination of zinc, magnesium and vitamin B-6. Some research shows that this combination can help raise testosterone levels. In the trial, subjects took a daily dose of ZMA (which included 30 mg zinc monomethionine, 450 mg magnesium aspartate and 10.5 mg vitamin B-6) at night during 7 weeks. Other hormones like IGF also increased, while the stress hormone, cortisol was reduced, creating an overall more favorable hormone profile. Not surprisingly, muscle performance also improved. (n) This paper is surrounding in controversy, however, because one of the scientists involved also holds the trademark for ZMA, and the research is company-funded.
It is suggested [16,37] that another mechanism for the effect of creatine could be enhanced muscle glycogen accumulation and GLUT4 expression, when creatine supplementation is combined with a glycogen depleting exercise. Whereas it has been observed  that creatine supplementation alone does not enhance muscle glycogen storage. Hickner et al  observed positive effects of creatine supplementation for enhancing initial and maintaining a higher level of muscle glycogen during 2 hours of cycling. In general, it is accepted that glycogen depleting exercises, such as high intensity or long duration exercise should combine high carbohydrate diets with creatine supplementation to achieve heightened muscle glycogen stores .
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.
Jager et al  observed 1.17 and 1.29 greater peak plasma creatine concentration 1 hour after ingesting creatine pyruvate compared to isomolar amount of CM and creatine citrate respectively. However time to peak concentration, and velocity constants of absorption and elimination, was the same for all three forms of creatine. Although not measured in this study it is questionable that these small differences in plasma creatine concentrations would have any effect on the increase of muscle creatine uptake. Jäger et al  investigated the effects of 28-days of creatine pyruvate and citrate supplementation on endurance capacity and power measured during an intermittent handgrip (15 s effort per 45s rest) exercise in healthy young athletes. The authors used a daily dose protocol with the intention to slowly saturate muscle creatine stores. Both forms of creatine showed slightly different effects on plasma creatine absorption and kinetics. The two creatine salts significantly increased mean power but only pyruvate forms showed significant effects for increasing force and attenuating fatigability during all intervals. These effects can be attributed to an enhanced contraction and relaxation velocity as well as a higher blood flow and muscle oxygen uptake. On the other hand, the power performance measured with the citrate forms decreases with time and improvements were not significant during the later intervals. In spite of these positive trends further research is required about the effects of these forms of creatine as there is little or no evidence for their safety and efficacy. Furthermore the regularity status of the novel forms of creatine vary from country to country and are often found to be unclear when compared to that of CM .
Creatine ethyl ester is more a pronutrient for creatinine rather than creatine, and was originally created in an attempt to bypass the creatine transporter. It is currently being studied for its potential as a treatment for situations in which there is a lack of creatine transporters (alongside cyclocreatine as another possible example). Its efficacy may rely on intravenous administration, however.
Carbohydrates provide quick energy in an anaerobic environment (high-intensity exercise), while fats provide sustained energy during periods of high oxygen availability (low-intensity exercise or rest). The breakdown of carbohydrates, fats, and ketones produces ATP (adenosine triphosphate). When cells use ATP for energy, this molecule is converted into adenosine diphosphate (ADP) and adenosine monophosphate (AMP). Creatine exists in cells to donate a phosphate group (energy) to ADP, turning this molecule back into ATP.
Cyclocreatine appears to be passively diffused through membranes and not subject to the creatine transporter, which can be beneficial for cases where creatine transporter function is compromised (creatine non-response and SLG6A8 deficiency). Similar to other forms of creatine, it buffers ATP concentrations, although its efficacy as a supplement in otherwise healthy people is currently unknown.
This period also saw the rise of anabolic steroids in bodybuilding and many other sports. In bodybuilding lore, this is partly attributed to the rise of "mass monsters", beginning with Arnold Schwarzenegger, Sergio Oliva, and Lou Ferrigno in the late 1960s and early 1970s, and continuing through the 1980s with Lee Haney, the 1990s with Dorian Yates, Ronnie Coleman, and Markus Rühl, and up to the present day. Bodybuilders such as Greg Kovacs attained mass and size never seen previously but were not successful at the pro level. Others were renowned for their spectacular development of a particular body part, like Tom Platz or Paul Demayo for the leg muscles. At the time of shooting Pumping Iron, Schwarzenegger (while never admitting to steroid use until long after his retirement) said that "you have to do anything you can to get the advantage in competition". He would later say that he does not regret using anything.
Injections of creatine are known to be neuroprotective against low oxygen levels (hypoxia) even to neonatal rats. This is thought to be associated with the increased collective pool of phosphocreatine and creatine. Since oral ingestion of creatine by the mother increases brain concentrations of creatine by 3.6% in the fetus prior to birth, it is thought to be protective in the fetuses subject to hypoxic (low oxygen) stressors, such as a caesarean section.
You burn calories during strength training, and your body continues to burn calories after strength training (just like you do after aerobic exercise), a process called "excess post-exercise oxygen consumption" or EPOC, according to the American Council on Exercise. (13) When you do strength, weight, or resistance training, your body demands more energy based on how much energy you’re exerting (meaning the tougher you’re working, the more energy is demanded). That means more calories burned during the workout, and more calories burned after the workout, too, while your body is recovering to a resting state.
Unfortunately, many people haven't gotten the message that strong is in. Indeed, statistics on strength training are grim: According to the Centers for Disease Control and Prevention (CDC), less than 30 percent of American adults engage in muscle-strengthening activities like lifting weights or doing push-ups at least twice a week—the recommendations set out by the government.
Stand on one foot with the arch and heel hanging off of the edge of a step or platform. Hold onto something if you need help balancing. Drop your heel all the way down below the step, and then rise all the way up on your toes. Hold dumbbells to make it harder. If you can balance without holding on to something, you’ll work your core muscles, too. You'll also build more stable joints in the other leg.
In summary, creatine salts have been show to be less stable than CM. However the addition of carbohydrates could increase their stability . The potential advantages of creatine salts over CM include enhanced aqueous solubility and bioavailability which would reduce their possible gastrointestinal adverse effects . The possibility for new additional formulation such as tablets or capsules is interesting for its therapeutic application due to its attributed better dissolution kinetics and oral absorption compared to CM . However more complete in vivo pharmaceutical analysis of creatine salts are required to fully elucidate their potential advantages/disadvantages over the currently available supplement formulations.
Though weight training can stimulate the cardiovascular system, many exercise physiologists, based on their observation of maximal oxygen uptake, argue that aerobics training is a better cardiovascular stimulus. Central catheter monitoring during resistance training reveals increased cardiac output, suggesting that strength training shows potential for cardiovascular exercise. However, a 2007 meta-analysis found that, though aerobic training is an effective therapy for heart failure patients, combined aerobic and strength training is ineffective; "the favorable antiremodeling role of aerobic exercise was not confirmed when this mode of exercise was combined with strength training".
^ Mangano, Kelsey M.; Sahni, Shivani; Kiel, Douglas P.; Tucker, Katherine L.; Dufour, Alyssa B.; Hannan, Marian T. (February 8, 2017). "Dietary protein is associated with musculoskeletal health independently of dietary pattern: the Framingham Third Generation Study". The American Journal of Clinical Nutrition. 105 (3): 714–722. doi:10.3945/ajcn.116.136762. PMC 5320406. PMID 28179224 – via ajcn.nutrition.org.
Another study demonstrated that females receiving 4 days of high-dose creatine intake (20 g/day) followed by low-dose creatine intake (5 g/day) during 10 weeks of resistance training (3hours/week) increased muscle PCr concentrations by 6%. Also, maximal strength of the muscle groups trained increased by 20-25%, maximal intermittent exercise capacity of the arm flexors increased by 10-25% and fat-free mass increased by 60% .