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).
A child’s ability to regenerate high energy phosphates during high intensity exercise is less than that of an adult. Due to this, creatine supplementation may benefit the rate and use of creatine phosphate and ATP rephosporylation. However, performance in short duration high-intensity exercise can be improved through training therefore supplementation may not be necessary [54].

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 [38] that creatine supplementation alone does not enhance muscle glycogen storage. Hickner et al [15] 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 [39].
The failure of creatine to improve physical performance in these conditions is thought to be related to the myopathies in general, which are known to result in less phosphocreatine in skeletal muscle,[568] associated with reduced expression of the creatine transporter.[569] As creatine has once been noted to not accumulate in the skeletal muscle of people with DM1 given supplementation,[566] it is thought that the subjects did not respond to therapy.

That soreness you feel post-strength session may seem like a setback. Yet over time, you’ll come to acknowledge that it signifies you’re getting stronger. “You think, ‘I’ve done something worthwhile. My body is telling me I’ve had a workout.’ You look forward to the fatigue and interpret it in a positive way,” says John Spence, PhD, professor of physical education and recreation at the University of Alberta in Canada, who wrote a review on the effect of exercise on self-esteem. (Wondering how sore is too sore to work out? Here’s your answer.)

Recently, studies are coming out that show a general decline in testosterone levels of men in the United States and around the world. The trend is across the board and doesn’t appear to be caused simply by a decline in health, aging or an increase in obesity rates. It could be caused because of chemicals or environmental factors. In any case, low levels of testosterone can affect many areas of your health, including your ability to build muscle. If you suspect that you have low testosterone levels, you can ask your doctor to test you for it. In addition to traditional hormone therapies, there are also many natural ways to boost your levels including through supplements, some of which will be discussed later in this article.
Elsewhere, it has been noted that in chronic progressive external ophthalmoplegia (CPEO, a progressive weakening of the muscles around the eye and a mitochondrial disorder), there was a failure of creatine supplementation to benefit symptoms when subjects were provided 20g daily for four weeks.[483] Creatine supplementation failed again at 150mg/kg for six weeks in people with either CPEO or another disorder associated with single gene deletions affecting the eyes (Kearns–Sayre syndrome, KSS) in improving muscular function.[484]
The main consequence to using weight training exercises is the increase in muscle strength that you'll develop over time. You'll also develop stronger bones as well as gain a better general posture. In short, maintaining good muscle strength will allow your body to move more freely from the moment you wake up in the morning to the moment you fall asleep at night.

I’m glad you found some good information from this article. For any of these supplements, I would suggest talking to your doctor and pharmacist. I would suggest thinking about why you are interested in taking testosterone. Are you looking to increase muscle size? Bulk up? Knowing your fitness goals will help you determine which products are appropriate for you.

Still, any supplement should be used carefully and after discussion with a dietitian or doctor. There are some potential health risks and side effects that you should be aware of before taking creatine. Muscle cramping, nausea, diarrhea, dizziness, gastrointestinal pain, dehydration, weight gain, water retention, heat intolerance, and fever have all been linked to the supplement. (13)
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]

Dymatize Nutrition maximizes the benefits of protein in ISO-100 through its use of hydrolyzed 100% whey protein isolate. Designed to increase the absorption of protein, this fast-acting protein provides 25 grams of protein and 5.5 grams of BCAAs per serving, with no gluten or lactose. With a formula that aids in the instantaneous delivery of effective and advanced protein forms straight to the muscle, ISO-100 is able to repair and build muscle faster, resulting in the ability to reach fitness goals sooner rather than later. Keep Reading »
It has been argued that purposely overtraining for a brief period can be beneficial. One article published by Muscle & Fitness magazine stated that you can "Overtrain for Big Gains". It suggested that if one is planning a restful holiday and does not wish to inhibit their bodybuilding lifestyle too much, they should overtrain before taking the holiday, so the body can recuperate and grow during the prolonged rest period. Overtraining can be used advantageously, as when a bodybuilder is purposely overtrained for a brief period of time to super compensate during a regeneration phase. These are known as "shock micro-cycles" and were a key training technique used by Soviet athletes.[53]
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.

In another case, supplements touted as "myostatin blockers" were formulated from a type of sea algae. In a test tube, they effectively blocked the activity of the protein myostatin, which inhibits muscular growth in the body. The supplement ads implied that they'd enable you to develop unprecedented levels of muscular growth, but as it turned out, they didn't actually work in the human body.

For beginners, your own body weight might be enough to get you started. However, it can be hard to challenge your body without any additional resistance, so to progress, you'll need some equipment. If you decide to strength train at home, you'll want to invest in some basics, such as resistance bands, weights, and an exercise ball. Try to have a range of weights: a light set (3 to 5 pounds for women, 5 to 8 pounds for men), a medium set (5 to 10 pounds for women, 10 to 15 pounds for men), and a heavy set (10 to 20 pounds for women, 15 to 30 pounds for men).

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.

D-aspartic acid can also help to reduce cortisol levels. Cortisol is known as the “stress” hormone because its production increases during stressful situations. High cortisol levels can have many negative side effects, such as weight gain, muscle tissue breakdown, or increased blood sugar. Taking a supplement that includes cortisol can reduce stress and prevent excess fat storage or muscle loss.

If you are doing this on your own, but are overwhelmed and confused about strength training, I know how that feels. It can be scary enough to keep MOST people from starting, which is actually why we created our 1-on-1 Coaching Program. Our coach gets to know you, builds a program based on your experience and goals, will check your form on each movement (via video), and keep you accountable and on track!
Side-Effects: While the signs of a great body may make one think that there cannot be anything wrong with bodybuilding supplements, the facts speak otherwise. Bodybuilding supplements do have side-effects and you must listen to your trainer before giving in to the thoughts of buying one. Creatine can cause heart problems, kidney problems, dehydration, diarrhoea and muscle cramping. You must also discuss your medical history with the trainer. 
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 [38] that creatine supplementation alone does not enhance muscle glycogen storage. Hickner et al [15] 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 [39].
One study in elite swimmers subject to sprints (varying in length from 25-100m) failed to find benefit with creatine supplementation, although there was also a failure on leg extension strength, suggesting nonresponse.[399] This has been noted twice elsewhere with a similar protocol,[400][401] while one study in elite swimmers subject to single 50m or 100m sprints found benefit with supplementation[402] and one found benefit with six repeated 50m sprints by 2%, yet not ten repeated 25m sprints with elite male swimmers (females failed to find benefit).[403] Another study also noted benefits in elite swimmers on a sprinting protocol.[156] Overall, the evidence is quite limited and suggests either a mild, or more likely, no increase for elite swimmers, although one study confirming an increase in body and water weight[401] failed to find a decrement in performance.
Generally, you should consume about 20 grams of protein with some carbs shortly after a workout. During the post-workout anabolic window, you’ll also want to limit fats, which can slow the absorption of protein. While there is some recent research that suggests the window may actually extend up to several hours following exercise, there’s no harm in getting nutrients in early as long as you’re sticking to your overall caloric and macronutrient goals.
Cornelissen, V. A., Defoor, J. G., Stevens, A., Schepers, D., Hespel, P., Decramer, M., Mortelmans, L., Dobbels, F., Vanhaecke, J., Fagard, R. H., and Vanhees, L. Effect of creatine supplementation as a potential adjuvant therapy to exercise training in cardiac patients: a randomized controlled trial. Clin.Rehabil. 2010;24(11):988-999. View abstract.
Make no mistake: Eating for muscle is just as important as lifting for muscle. The foods you grab in the morning on the way to work, the meals you pack for lunch and mid-afternoon, what you put into your body immediately following your workout, and your final meal of the day impact your results as much as, if not more than, the number of reps you squeeze out at the end of a set. But in reality, it can be tough to stick to a "“clean"” diet when you'’re busy. We know that adding another layer of complexity to life in the form of reading food labels and studying ingredient lists just isn'’t an option for most of us. Not to mention actually preparing all those healthy meals.
You're aiming to kick start muscle hypertrophy, the cellular process that spurs growth. Researchers have found that the best way to initiate that process is by performing two or three sets of an exercise for six to 12 repetitions, with about 30 to 60 seconds' rest between sets. You're damaging the muscles with the work — then the protein you've been consuming will help build them back up even bigger.
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.

Taking high doses of creatine might harm the kidneys. Some medications can also harm the kidneys. Taking creatine with medications that can harm the kidneys might increase the chance of kidney damage.

Some of these medications that can harm the kidneys include cyclosporine (Neoral, Sandimmune); aminoglycosides including amikacin (Amikin), gentamicin (Garamycin, Gentak, others), and tobramycin (Nebcin, others); nonsteroidal anti-inflammatory drugs (NSAIDs) including ibuprofen (Advil, Motrin, Nuprin, others), indomethacin (Indocin), naproxen (Aleve, Anaprox, Naprelan, Naprosyn), piroxicam (Feldene); and numerous others.

HMB supplementation is claimed to build muscle size and strength and promote fat loss in conjunction with a strength program. Studies of HMB have shown some benefit to strength athletes in building muscle bulk but the benefits are relatively small and the cost of HMB is high. The effective dose seems to be 3 grams/day divided into 1 gram three times a day. Probably not worth taking. Beta-alanine is the new guy on the block and has not been evaluated sufficiently in my view. It may provide some advantage in high-intensity sports like weight training but it’s much too early to know that it does. Some early studies are flawed. Save your money or try creatine instead.
Creatine is not an essential nutrient[19] as it is naturally produced in the human body from the amino acids glycine and arginine, with an additional requirement for methionine to catalyze the transformation of guanidinoacetate to creatine. In the first step of the biosynthesis these two amino acids are combined by the enzyme arginine:glycine amidinotransferase (AGAT, EC: to form guanidinoacetate, which is then methylated by guanidinoacetate N-methyltransferase (GAMT, EC:, using S-adenosyl methionine as the methyl donor. Creatine itself can be phosphorylated by creatine kinase to form phosphocreatine, which is used as an energy buffer in skeletal muscles and the brain.
Collectively the above investigations indicate that creatine supplementation can be an effective strategy to maintain total creatine pool during a rehabilitation period after injury as well as to attenuate muscle damage induced by a prolonged endurance training session. In addition, it seems that creatine can act as an effective antioxidant agent after more intense resistance training sessions.