Athletes are known to experiment with dietary supplements and often they discover performance enhancing effects of foods and nutrients only for research to catch up some years later and confirm the anecdotes. Strength athletes have known for a long time that training with weights for muscle mass and strength gains requires and increase in the protein content of the diet to facilitate muscle growth and recovery. Protein supplements are less commonly consumed by endurance athletes. A review of the literature published in the Journal of Nutrition in 20061 looked at the effect a protein drink on muscle function, general fatigue and recovery in exercising athletes. They found that a protein supplement decreased muscle damage, increased the oxygen carrying capacity of the blood, and increased recovery of the muscle from fatigue especially after eccentric exercise.
The exact amount of protein required by athletes really depends on the intensity and type of the exercise regimen undertaken, but it is generally recommended that 1 g per pound of lean body weight is enough for most non-drug assisted athletes involved in strength building programmes. Protein can be used by the body to rebuild muscle because amino acids are needed to construct protein tissue following exercise and the branched chain amino acids (BCAA) can stimulate protein synthesis (here). In addition, the BCAA also serve as an energy source for skeletal muscle. During exercise the BCAA are oxidised for energy, while pyruvate is transported to the liver and used to maintain blood glucose levels via gluconeogenesis. Increasing dietary BCAA at time of exercise therefore supplies a source of the BCAA to prevent this degradation and spares muscle tissue.
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