Spero Karas, MD, assistant professor of orthopaedics in the division of sports medicine at Emory University, says that testosterone, the male hormone responsible for muscle growth, maxes out between the ages of 16 and 18. It reaches a plateau during the 20s and then begins to decline. As a result, muscle building after the adolescent years can be challenging, he says.
Ghost Size takes the cake for muscle growth. The key to this formula is epicatechin, an antioxidant found in chocolate and certain plants that is linked to a wide array of benefits. These include increased nitric oxide produciton, better oxygenation to the brain, and muscle growth: epicatechin appears to inhibit myostatin, which suppresses muscle growth, and the dosage found in Ghost Size is in line with studies that examined this effect.
Discomfort can arise from other factors. Individuals who perform large numbers of repetitions, sets, and exercises for each muscle group may experience a burning sensation in their muscles. These individuals may also experience a swelling sensation in their muscles from increased blood flow (the "pump"). True muscle fatigue is experienced as a marked and uncontrollable loss of strength in a muscle, arising from the nervous system (motor unit) rather than from the muscle fibers themselves. Extreme neural fatigue can be experienced as temporary muscle failure. Some weight training programs, such as Metabolic Resistance Training, actively seek temporary muscle failure; evidence to support this type of training is mixed at best. Irrespective of their program, however, most athletes engaged in high-intensity weight training will experience muscle failure during their regimens.
Without supplementation, creatine is formed primarily in the liver, with minor contributions from the pancreas and kidneys. The two amino acids, glycine and arginine, combine via the enzyme Arginine:Glycine amidinotransferase (AGAT) to form ornithine and guanidoacetate. This is the first of two steps in creatine synthesis, and although rare, any deficiency of this enzyme can result in mild mental retardation and muscular weakness. AGAT is also the primary regulatory step, and an excess of dietary creatine can suppress activity of AGAT to reduce creatine synthesis by reducing AGAT mRNA levels, rather than resulting in competitive inhibition.
Heath is an unlikely Mr. Olympia. He grew up on playgrounds in Seattle playing basketball. His backcourt mate on the 1998 state championship team at Rainier Beach High School was Jamal Crawford, still in the N.B.A. Heath, just 5 feet 9 inches and a naturally chiseled 175 pounds, got a Division I basketball scholarship at the University of Denver. He majored in business and averaged 1.3 points over four seasons.
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.