^ 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.
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]

Weight training aims to build muscle by prompting two different types of hypertrophy: sarcoplasmic and myofibrillar. Sarcoplasmic hypertrophy leads to larger muscles and so is favored by bodybuilders more than myofibrillar hypertrophy, which builds athletic strength. Sarcoplasmic hypertrophy is triggered by increasing repetitions, whereas myofibrillar hypertrophy is triggered by lifting heavier weight.[23] In either case, there is an increase in both size and strength of the muscles (compared to what happens if that same individual does not lift weights at all), however, the emphasis is different.


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.
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]
The bulking and cutting strategy is effective because there is a well-established link between muscle hypertrophy and being in a state of positive energy balance.[19] A sustained period of caloric surplus will allow the athlete to gain more fat-free mass than they could otherwise gain under eucaloric conditions. Some gain in fat mass is expected, which athletes seek to oxidize in a cutting period while maintaining as much lean mass as possible.

Contrary to certain rumors that animal-based protein is more suitable to trigger muscle growth than plant-based protein, a study by Mangano et al. (2017) could not provide any evidence for this. In contrast, if combined properly, plant-based protein can even have a higher biological quality. A combination of one part wheat protein (e.g. seitan) and two parts soy protein (e.g. tofu) has thus been favored by many bodybuilders. Some bodybuilders, such as Patrik Baboumian and Robert Cheeke, follow a strict vegan diet.[37]
Some bodybuilders use drugs such as anabolic steroids and precursor substances such as prohormones to increase muscle hypertrophy. Anabolic steroids cause hypertrophy of both types (I and II) of muscle fibers, likely caused by an increased synthesis of muscle proteins. They also provoke undesired side effects including hepatotoxicity, gynecomastia, acne, the early onset of male pattern baldness and a decline in the body's own testosterone production, which can cause testicular atrophy.[43][44][45] Other performance-enhancing substances used by competitive bodybuilders include human growth hormone (HGH), which can cause acromegaly.
In natural contests, the testing protocol ranges among organizations from lie detectors to urinalysis. Penalties also range from organization to organization from suspensions to strict bans from competition. It is also important to note that natural organizations also have their own list of banned substances and it is important to refer to each organization's website for more information about which substances are banned from competition. There are many natural bodybuilding organizations; some of the larger ones include: MuscleMania, Ultimate Fitness Events (UFE), INBF/WNBF, and INBA/PNBA. These organizations either have an American or worldwide presence and are not limited to the country in which they are headquartered.
In the last week leading up to a contest, bodybuilders usually decrease their consumption of water, sodium, and carbohydrates, the former two to alter how water is retained by the body and the latter to reduce glycogen in the muscle. The day before the show, water is removed from the diet, and diuretics may be introduced, while carbohydrate loading is undertaken to increase the size of the muscles through replenishment of their glycogen. The goal is to maximize leanness and increase the visibility of veins, or "vascularity". The muscular definition and vascularity are further enhanced immediately before appearing on stage by darkening the skin through tanning products and applying oils to the skin to increase shine. Some competitors will eat sugar-rich foods to increase the visibility of their veins. A final step, called "pumping", consists in performing exercises with light weights or other kinds of low resistance (for instance two athletes can "pump" each other by holding a towel and pulling in turn), just before the contest, to fill the muscles with blood and further increase their size and density.

Although muscle stimulation occurs in the gym (or home gym) when lifting weights, muscle growth occurs afterward during rest periods. Without adequate rest and sleep (6 to 8 hours), muscles do not have an opportunity to recover and grow.[citation needed] Additionally, many athletes find that a daytime nap further increases their body's ability to recover from training and build muscles. Some bodybuilders add a massage at the end of each workout to their routine as a method of recovering.[51]


Bodybuilding is the use of progressive resistance exercise to control and develop one's musculature for aesthetic purposes.[1] An individual who engages in this activity is referred to as a bodybuilder. In competitive bodybuilding, bodybuilders appear in lineups and perform specified poses (and later individual posing routines) for a panel of judges who rank the competitors based on criteria such as symmetry, muscularity, and conditioning. Bodybuilders prepare for competitions through the elimination of nonessential body fat, enhanced at the last stage by a combination of extracellular dehydration and carbohydrate loading, to achieve maximum muscular definition and vascularity, as well as tanning to accentuate the contrast of the skin under the spotlights. Bodybuilders may use anabolic steroids and other performance-enhancing drugs to build muscles.
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