Nutrition
Muscle tension and the availability of amino acids are essential for muscle protein synthesis and muscle growth. muscle growth growth. Many studies have shown that supplementation with protein or amino acids before or after exercise promotes protein synthesis. These supplements provide amino acids that are necessary to promote tissue repair and muscle hypertrophy. Proteins also stimulate insulin secretion, which accelerates the transport of amino acids into muscle cells and gives protein synthesis a boost.
Researchers at McMaster University in Canada found that milk protein consumed after training with weights stimulated post-workout protein synthesis more than soy protein. This study examined the effect of post-workout supplementation consisting of either fat-free milk, fat-free soy protein or carbohydrates(maltodextrin) on protein synthesis in 56 healthy young men participating in a 12-week weights training program. Muscle mass increased in most members of the group that consumed fat-free milk after training.
Fat-free milk is cheap, readily available and a good choice for bodybuilders looking to maximize muscle growth.
(American Journal Clinical Nutrition, 86: 373-381, 2007)
The "Holy Grail" of supplements is a supplement that increases performance after just a few days of use. Substances such as anabolic steroids, growth hormones, insulin and IGF-1 build strength and mass, but they have little or no short-term effect. The intake of creatine monohydrate during the days leading up to a weightlifting competition, soccer match, golf tournament or track and field event could lead to a measurable increase in performance. Creatine monohydrate increases the amount of the available high-energy cellular energy carrier creatine phosphate and stimulates the synthesis of protein.
Researchers at the University of Oklahoma, led by Joel Cramer, found that three days of isokinetic training combined with 8 days of creatine supplementation (21 grams per day) increased strength and speed in 25 college-aged men. The scientists were unable to detect any changes in neuromuscular function using an electrotromyograph (measurement of muscle activation by the nervous system). Short-term training in conjunction with creatine supplementation is helpful for increasing strength and preparing athletes for competition.
(Journal Strength Conditioning Research, 21: 668-677, 2007)
A modern legend in the field of sport says that creatine monohydrate triggers muscle cramps and promotes dehydration. Without scientific evidence, the media, some trainers and athletes continue to spread this misinformation.
Scientists at the University of Oklahoma, led by Vincent Dalbo, have concluded that the exact opposite is true: creatine improves heat tolerance and helps maintain plasma volume during heat training. Blood plasma is the cell-free portion of blood that is essential for maintaining a stable body temperature and cardiac output (blood flow through the heart) during exercise. Even in dehydrated people, creatine improved exercise capacity and helped combat the negative effects of reduced body water. Let's put this modern legend to rest! Creatine supplements do not cause dehydration or muscle cramps. Instead, they improve the capacity for temperature regulation during exercise and improve some areas of athletic performance.
(British Journal Sports Medicine, in press, published online January 9, 2008)
People in developed countries are living longer than ever before and very old athletes (90 and older) are increasingly participating in Masters sports competitions. While a long life is desirable, quality of life in old age is even more important.
An Italian study came to the conclusion that L-carnitine supplements (2 grams per day for six months) reduced fatigue and improved mental function in 66 men and women over the age of 100. The results were compared with a control group of the same age group who took a placebo. Members of the carnitine group gained 8.4 pounds of lean body mass, lost 4 pounds of fat, ran 4 meters further in a 6-minute walk test and reduced their cholesterol levels by 15 percent. The subjects taking supplements also showed improved mental function and increased physical activity. The supplement was well tolerated and none of the study participants reported any side effects. Other studies have not shown these beneficial effects in younger subjects.
(American Journal of Clinical Nutrition, 86: 1738-1744, 2007)
Nitric oxide (NO) is a chemical secreted by the inner lining of blood vessels that helps control blood flow in muscles and other types of tissue (e.g. the penis). An increase in nitric oxide release could improve blood flow to muscles during exercise in bodybuilders. Some athletes use supplements designed to increase nitric oxide production, but these products have no proven benefits to date.
A study conducted at the University of Memphis under the direction of Richard Bloomer showed that Glycine-propionyl-L-carnitine (GPLC) supplements (GlycoCarn: 3 grams per day in combination with 1,044 milligrams of glycine over four weeks) increased nitric oxide production in men training with weights. The scientists restricted the blood supply to the arm using a cuff for 6 minutes and then released the cuff. This caused a reflex increase in muscle blood flow to the arm, which was partly due to nitric oxide release through the blood vessels. Blood samples taken after the cuff was released showed that nitric oxide levels (as measured by the indirect markers nitrite and nitrate) were highest when GPLC was ingested. We do not know whether increasing nitric oxide levels promotes muscle growth in bodybuilders.
(Journal International Society Sports Nutrition, 4: 22, 2007, published online)
