Supplements are athletes and researchers in a quest to achieve new levels of human performance. Some are fairly innocuous, and lead to little or no performance gains, while others result in severe health consequences and sometimes death. According to "Essentials of Strength Training and Conditioning," distinguish between dietary supplements, including vitamins, minerals, herbs, amino acids or any blend of these nutrients, from drugs, including hormones and ergogenic aids that change the body's structure of function. The most commonly-consumed, and consistently effective, supplements for weightlifting include carbohydrate, protein, essential amino acids and creatine.
Carbohydrate-Protein Supplements
Carbohydrate is a macronutrient, or a nutrient the body must consume in large quantities to support its energy needs. Foods high in carbohydrates, as well as carbohydrate-based beverages and sports bars have consistently demonstrated performance-enhancing effects both before and after weightlifting. "Carb-loading" increases glycogen in the muscles and prevents the body from using its protein stores for energy. Protein is also a macronutrient, and plays a vital role in the growth and repair of muscle tissue. Protein supplementation is also effective for decreasing the rate of muscle tissue breakdown following weightlifting, leading to improvements in muscle mass over time. Combined, carbohydrate-protein supplements are typically most effective within one hour following a weightlifting workout.
Essential Amino Acids
Protein molecules are composed of amino acids, some of which can be produced by the body. Essential amino acids, or those which cannot be produced by the body, may boost the body's production of testosterone, human growth hormone, insulin and insulin-like growth factor, resulting in increased muscle size and strength, as well as a decrease in body fat. Research has demonstrated that essential amino acid supplements, including isoleucine, leucine, valine, lysine, phenylalanine, methionine, tryptophan and threonine are effective for stimulating protein synthesis both before and after weightlifting beyond that of a placebo.
Amino acid derivatives, such as HMB, Beta-Alanine and L-Carnitine have also been of interest to weightlifters. These supplements have experienced much more equivocal effects on weightlifting performance than essential amino acids, but may be associated with some modest improvements in muscle performance and physical work capacity when taken consistently for several weeks.
Creatine
Creatine is an organic compound that is synthesized in the human body, but can also be consumed through meat, fish and poultry. Creatine supplements have consistently demonstrated performance enhancing effects when athletes consume about 20 to 30 g for up to two weeks. Creatine's effects on muscle power, strength and muscle mass last from a few days to a few weeks following creatine-loading. Creatine is considered a legal substance by the International Olympic Committee, despite some controversy about its side effects, such as gastrointestinal irritation and possible long-term organ damage.
Caffeine
Caffeine is not a dietary supplement, but a drug. However, because of its wide use and consistent performance-enhancing effects, it is often part of any supplement discussion. While typically used as an aerobic endurance enhancer, consuming about 3 to 9 mg of caffeine prior to weightlifting enhances power for short-duration, high-intensity maneuvers. Caffeine intake greater than 9 mg are associated with a greater risk of side effects, such as heart tremors, dehydration, nervousness and gastrointestinal problems.
References
- "Essentials of Exercise Physiology"; William D. McArdle, et al.; 2006
- "Essentials of Strength Training and Conditioning"; Thomas Baechle and Roger Earle (Editors); 2008
- "Physiology of Sport and Exercise"; Jack H. Wilmore and David L. Costill; 2004
- "Strength and Conditioning Journal"; Timing and Composition of Protein/Amino Acid Supplementation; Jose Antonio, PhD; February 2008
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