Muscle growth is more difficult to achieve in older adults than younger adults because of biological aging, which leads to many metabolic changes detrimental to muscle growth; for instance, by diminishing growth hormone and testosterone levels. Some recent clinical studies have shown that low-dose HGH treatment for adults with HGH deficiency changes the body composition by increasing muscle mass, decreasing fat mass, increasing bone density and muscle strength, improves cardiovascular parameters, and affects the quality of life without significant side effects.[unreliable medical source?]
The general strategy adopted by most present-day competitive bodybuilders is to make muscle gains for most of the year (known as the "off-season") and, approximately 12–14 weeks from competition, lose a maximum of body fat (referred to as "cutting") while preserving as much muscular mass as possible. The bulking phase entails remaining in a net positive energy balance (calorie surplus). The amount of a surplus in which a person remains is based on the person's goals, as a bigger surplus and longer bulking phase will create more fat tissue. The surplus of calories relative to one's energy balance will ensure that muscles remain in a state of anabolism.
The important role of nutrition in building muscle and losing fat means bodybuilders may consume a wide variety of dietary supplements. Various products are used in an attempt to augment muscle size, increase the rate of fat loss, improve joint health, increase natural testosterone production, enhance training performance and prevent potential nutrient deficiencies.
The first U.S. Women's National Physique Championship, promoted by Henry McGhee and held in Canton, Ohio in 1978, is generally regarded as the first true female bodybuilding contest—that is, the first contest where the entrants were judged solely on muscularity. In 1980, the first Ms. Olympia (initially known as the "Miss" Olympia), the most prestigious contest for professionals, was held. The first winner was Rachel McLish, who had also won the NPC's USA Championship earlier in the year. The contest was a major turning point for female bodybuilding. McLish inspired many future competitors to start training and competing. In 1985, a movie called Pumping Iron II: The Women was released. It documented the preparation of several women for the 1983 Caesars Palace World Cup Championship. Competitors prominently featured in the film were Kris Alexander, Lori Bowen, Lydia Cheng, Carla Dunlap, Bev Francis, and McLish. At the time, Francis was actually a powerlifter, though she soon made a successful transition to bodybuilding, becoming one of the leading competitors of the late 1980s and early 1990s.
Bodybuilding became more popular in the 1950s and 1960s with the emergence of strength and gymnastics champions, and the simultaneous popularization of bodybuilding magazines, training principles, nutrition for bulking up and cutting down, the use of protein and other food supplements, and the opportunity to enter physique contests. The number of bodybuilding organizations grew, and most notably the International Federation of Bodybuilders (IFBB) was founded in 1946 by Canadian brothers Joe and Ben Weider. Other bodybuilding organizations included the Amateur Athletic Union (AAU), National Amateur Bodybuilding Association (NABBA), and the World Bodybuilding Guild (WBBG). Consequently, the male-dominated contests grew both in number and in size. Besides the many "Mr. XXX" (insert town, city, state, or region) championships, the most prestigious titles[according to whom?] were Mr. America, Mr. World, Mr. Universe, Mr. Galaxy, and ultimately Mr. Olympia, which was started in 1965 by the IFBB and is now considered the most important bodybuilding competition in the world.
Some Bodybuilders often split their food intake into 5 to 7 meals of equal nutritional content and eat at regular intervals (e.g. every 2 to 3 hours). This approach serves two purposes: to limit overindulging in the cutting phase, and to allow for the consumption of large volumes of food during the bulking phase. Eating more frequently does not increase basal metabolic rate when compared to 3 meals a day. While food does have a metabolic cost to digest, absorb, and store, called the thermic effect of food, it depends on the quantity and type of food, not how the food is spread across the meals of the day. Well-controlled studies using whole-body calorimetry and doubly labeled water have demonstrated that there is no metabolic advantage to eating more frequently.
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. 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.
An article by Muscle & Fitness magazine, "Overtrain for Big Gains", claimed that overtraining for a brief period can be beneficial. 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.
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. 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.
The winner of the annual IFBB Mr. Olympia contest is generally recognized as the world's top male professional bodybuilder. Since 1950, the NABBA Universe Championships have been considered the top amateur bodybuilding contests, with notable winners such as Reg Park, Lee Priest, Steve Reeves, and Arnold Schwarzenegger. Winners generally go on to become professional athletes.