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.
^ "Popular sports supplements contain meth-like compound". USA Today. October 25, 2013. Cohen said researchers informed the FDA in May about finding the new chemical compound in Craze. The team found the compound — N,alpha-diethylphenylethylamine — has a structure similar to methamphetamine, a powerful, highly addictive, illegal stimulant drug. They believe the new compound is likely less potent than methamphetamine but greater than ephedrine.
Creatine is known to occur in highly concetrated levels in chicken photoreceptors, relative to other parts of the eye (10-15mM[466]) alongside high levels of creatine kinase.[466] The creatine transporter in human eyes also seems to be concentrated in the photoreceptors,[468] which are known to be susceptible to hypoxic cellular death[471][472] which, for humans, usually means retinal detachment.[473]
The sexual hormone can encourage fair behavior. For the study, subjects took part in a behavioral experiment where the distribution of a real amount of money was decided. The rules allowed both fair and unfair offers. The negotiating partner could subsequently accept or decline the offer. The fairer the offer, the less probable a refusal by the negotiating partner. If no agreement was reached, neither party earned anything. Test subjects with an artificially enhanced testosterone level generally made better, fairer offers than those who received placebos, thus reducing the risk of a rejection of their offer to a minimum. Two later studies have empirically confirmed these results.[75][76][77] However men with high testosterone were significantly 27% less generous in an ultimatum game.[78] The Annual NY Academy of Sciences has also found anabolic steroid use which increase testosterone to be higher in teenagers, and this was associated with increased violence.[79] Studies have also found administered testosterone to increase verbal aggression and anger in some participants.[80]

Another double-blind study supplemented with 18.75 g/day of creatine monohydrate for 5 days prior to high-intensity intermittent work to exhaustion, and then 2.25 g/day during testing. The workouts consisted of cycling to exhaustion using several protocols: (a) nonstop, (b) 60 seconds work/120 seconds rest, (c) 20 seconds work/40 seconds rest, and (d) 10 seconds work/20 seconds rest. Creatine supplementation significantly increased the total work time for all four protocols [13].
Creatine is marketed as "nature's muscle builder" and "the most legitimate sports supplement around." Professional and amateur athletes alike are gobbling up this alleged ergogenic aid, hoping to increase their strength and performance. Creatine supplementation is claimed to increase muscle power by playing a role in the transfer of energy to help the muscle contract. Supplement labels state that "creatine is converted to phosphocreatine, which is important for short energy bursts such as sprinting and weight lifting" and that "depletion of phosphocreatine can result in muscle fatigue and fading muscle power." Claims are also made that supplementation increases muscle body mass.

These terms combine the prefix iso- (meaning "same") with tonic ("strength") and plio- ("more") with metric ("distance"). In "isotonic" exercises the force applied to the muscle does not change (while the length of the muscle decreases or increases) while in "plyometric" exercises the length of the muscle stretches and contracts rapidly to increase the power output of a muscle.
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.

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.
How to do it: Begin with your head, neck, and shoulders comfortably fixed against a stability or Swiss ball and both feet firmly planted on the ground, knees bent at 90°. (This is also known as table top position.) Either stretch your arms straight up above your chest with your hands clasped to maximize the balance and stability challenge, or down on either side in case you begin to slip or tip over. As with the other bridge motions, simply lower your hips toward the floor then drive them toward the ceiling. Lower and repeat.
In the 1970s, bodybuilding had major publicity thanks to the appearance of Arnold Schwarzenegger, Franco Columbu, Lou Ferrigno, and others in the 1977 docudrama Pumping Iron. By this time, the IFBB dominated the competitive bodybuilding landscape and the Amateur Athletic Union (AAU) took a back seat. The National Physique Committee (NPC) was formed in 1981 by Jim Manion,[7] who had just stepped down as chairman of the AAU Physique Committee. The NPC has gone on to become the most successful bodybuilding organization in America and is the amateur division of the IFBB. The late 1980s and early 1990s saw the decline of AAU-sponsored bodybuilding contests. In 1999, the AAU voted to discontinue its bodybuilding events. 

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
A maintenance phase of 2g daily appears to technically preserve creatine content in skeletal muscle of responders either inherently or after a loading phase, but in sedentary people or those with light activity, creatine content still progressively declines (although it still higher than baseline levels after six weeks) and glycogen increases seem to normalize. This maintenance dose may be wholly insufficient for athletes, a 5g maintenance protocol may be more prudent.
Adequate hydration is essential to muscle building, yet few people get enough water, even without daily exercise. So in addition to the daily 8 to 10 glasses of water recommended by the Dietary Guidelines for Americans, Karas suggests an additional 12 to 16 ounces before working out. He then recommends another 8 to 10 ounces for every 15 minutes of vigorous exercise.
Overtraining occurs when a bodybuilder has trained to the point where his workload exceeds his recovery capacity. There are many reasons why overtraining occurs, including lack of adequate nutrition, lack of recovery time between workouts, insufficient sleep, and training at a high intensity for too long (a lack of splitting apart workouts). Training at a high intensity too frequently also stimulates the central nervous system (CNS) and can result in a hyperadrenergic state that interferes with sleep patterns.[51] To avoid overtraining, intense frequent training must be met with at least an equal amount of purposeful recovery. Timely provision of carbohydrates, proteins, and various micronutrients such as vitamins, minerals, phytochemicals, even nutritional supplements are acutely critical. A mental disorder informally called “bigorexia” (by analogy with anorexia) may be held accountable of some people overtraining. Sufferers feel as if they are never big enough or muscular enough, which forces them to overtrain in order to try and reach their goal physique.[52]
Intensive weight training causes micro-tears to the muscles being trained; this is generally known as microtrauma. These micro-tears in the muscle contribute to the soreness felt after exercise, called delayed onset muscle soreness (DOMS). It is the repair of these micro-traumas that results in muscle growth. Normally, this soreness becomes most apparent a day or two after a workout. However, as muscles become adapted to the exercises, soreness tends to decrease.[22]
Creatine, the amino acid, naturally helps your body produce more adenosine triphosphate, or ATP, a small molecule that’s actually your body's primary energy source. But research shows that your body is only capable of storing enough ATP for 8 to 10 seconds of high-intensity exercise — and after that, it needs to produce new ATP for you to continue. (9) 

It's woooooorkkkkkiiiinnnngggg!!! I've been working out without creatine for over a year and a half now and have been missing that extra boost at the end of a set of reps. Not anymore! Started to feel the creatine help out in my 4th workout since using this stuff. It's good, real good. Creatine is one of those only supplements that have actually been proven to increase strength and bursts of endurance at the end of a set, and it's that one thing that can turn a regular workout into something that you're proud of. Just buy it, it works, you won't be disappointed. Use 2 of their servings sizes though, you need 5mg not 2.5. No spoon in bag, you'll need a measuring cup. Mixes effortlessly in juice.

The rise in testosterone levels during competition predicted aggression in males but not in females.[90] Subjects who interacted with hand guns and an experimental game showed rise in testosterone and aggression.[91] Natural selection might have evolved males to be more sensitive to competitive and status challenge situations and that the interacting roles of testosterone are the essential ingredient for aggressive behaviour in these situations.[92] Testosterone produces aggression by activating subcortical areas in the brain, which may also be inhibited or suppressed by social norms or familial situations while still manifesting in diverse intensities and ways through thoughts, anger, verbal aggression, competition, dominance and physical violence.[93] Testosterone mediates attraction to cruel and violent cues in men by promoting extended viewing of violent stimuli.[94] Testosterone specific structural brain characteristic can predict aggressive behaviour in individuals.[95]