In order to achieve muscle growth (hypertrophy), bodybuilders focus in three main lines of action:

Resistance weight training
Specialised nutrition, incorporating extra protein and supplements where necessary
Adequate rest

Resistance weight training

German Bodybuilder Markus Rühl posing in Biberach an der Riß.Resistance weight training causes micro-tears to the muscles being trained; this is generally known as micro-trauma. These micro-tears in the muscle contribute to the soreness felt after exercise, called delayed onset muscle soreness (DOMS). It is the repair to these micro-trauma that result in muscle growth. Normally, this soreness becomes most apparent a day or two after a workout.

Nutrition
See also List of nutrition related topics
The high levels of muscle growth and repair achieved by bodybuilders require a specialised diet. Generally speaking, bodybuilders require between 500 to 1000 Calories (2000 to 4000 kilojoules) above their maintenance level of food energy while attempting to increase lean body mass. A sub-maintenance level of food energy is combined with cardiovascular exercise to lose body fat in preparation for a contest. The ratios of food energy from carbohydrates, proteins, and fats vary depending on the goals of the bodybuilder.

Bodybuilders usually split their food intake for the day into 5 to 7 meals of roughly equal nutritional content and attempt to eat at regular intervals (normally between 2 and 3 hours). This is thought to allow greater availability of nutrients, and may also assist with fat loss. This process is potentially a mechanism for increasing basal metabolic rate when compared to less frequent meals that have the same caloric sum, but this is disputed [3]. However, frequent feeding is an effective method of controlling blood sugar levels, which in turn will have an effect on hunger, energy levels, and muscle growth.[citation needed]


Carbohydrates
Having a large proportion of the diet come from carbohydrates gives the body enough energy to deal with the rigours of training and recovery. Bodybuilders require polysaccharides, which release energy more slowly than simple sugars. This is important as simple sugars cause an insulin response, which places the body in a state where it is likely to store additional food energy as fat rather than muscle, and which can waste energy that should be going towards muscle growth. However bodybuilders do ingest some simple sugars (often in form of pure glucose or maltodextrin) post-workout to replenish glycogen stores within the muscle.


Protein
It is recommended that bodybuilders receive 1 to 2 grams of protein per pound per day of body weight (2 to 5 g/kg) to help the body recover and build. It is a widely debated topic, with many arguing that 1 gram of protein per pound of body weight is ideal, and others recommending 1.5 or 2. There is much debate concerning the best type of protein to take. Meat, fish, eggs and dairy foods are high in protein, as are some nuts, seeds, beans and lentils. Casein or whey are often used to supplement the diet with additional protein. Whey protein is the type of protein contained in the most popular brands of protein supplements, and is preferred by many bodybuilders because of its high biological value. It is believed that protein needs to be consumed frequently throughout the day; however, the most important times for bodybuilders to consume protein are within 45 minutes of a workout and before going to sleep.


Protein Timing
The goal for anyone wishing to optimize muscle building and minimize the storage of excess calories as body fat is to eat as perfectly as possible so that the body is provided a steady stream of nutrients, and so that blood sugar levels also remain steady. An important way to accomplish this goal, besides eating high quality foods, is to eat small multiple meals, (every 2 to 3 hours). Since there is only a very small amount of amino acid in the bloodstream, to maintain an anabolic (muscle building) environment complete proteins must be eaten with every meal. It is the acute and large increase in the amount of amino acids in the blood that causes protein synthesis rates to increase as well as a decrease in protein breakdown.

Maintaining a positive nitrogen balance will prevent the body from dipping into its own muscle tissue (catabolism) to get nutrients it needs (like protein). This is why it is important to eat five to six protein-containing meals per day, (one about every two to three hours), to maintain a positive nitrogen balance, (which occurs from the breakdown of amino acids).

Eating small evenly spaced meals containing low GI carbohydrates helps to stabilize insulin levels. It may also be easier on the digestive system. However, studies have shown that eating frequent smaller meals will not raise the metabolic rate, burn more calories, or result in less body fat storage. [4]
Dietary supplements
Main article: Bodybuilding supplements
The important role of nutrition in building muscle means bodybuilders may consume a wide variety of dietary supplements. [1] Commonly used products include: essential fatty acid; amino acids; vitamin and mineral formulations; glucosamine and/or chondroitin; MSM (methylsulfonylmethane); thermogenics and creatine. These products are used in an effort to ensure adequate nutrition in an effort to gain additional size, though research on the effectiveness of the majority of such products remains to be seen.



Overtraining
Overtraining is generally regarded as one of the biggest and most common problems bodybuilders face. It refers to when a bodybuilder has trained to the point where his workload exceeds his recovery capacity. There are many reasons that 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 periodisation). Training at a high intensity too frequently also stimulates the central nervous system (CNS) too frequently, and can result in a hyper-adrenergic state that interferes with sleep patterns. 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.

It has been argued that overtraining can be beneficial. One article published by Muscle & Fitness magazine stated that you can "Overtrain for Big Gains"[citation needed]. It suggested that if one is planning a restful holiday and they do not wish to inhibit their bodybuilding lifestyle too much, they should overtrain before taking the holiday, so the body can rest easily and recuperate and grow.

More commonly however, 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. The vast amount of overtraining that occurs in average bodybuilders however, is generally unplanned and completely unnecessary.


Rest
Although muscle stimulation occurs in the gym lifting weights, muscle growth occurs afterward during rest. Without adequate rest and sleep, muscles do not have an opportunity to recover and build. About eight hours of sleep a night is desirable for the bodybuilder to be refreshed, although this varies from person to person. Additionally, many athletes find a daytime nap further increases their body's ability to build muscle