Exercise, protein metabolism, and muscle growth

Exercise has a profound effect on muscle growth, which can occur only if muscle protein synthesis exceeds muscle protein breakdown; there must be a positive muscle protein balance. 

Resistance exercise improves muscle protein balance, but, in the absence of food intake, the balance remains negative (i.e., catabolic). The response of muscle protein metabolism to a resistance exercise bout lasts for 24-48 hours; thus, the interaction between protein metabolism and any meals consumed in this period will determine the impact of the diet on muscle hypertrophy. 

Amino acid availability is an important regulator of muscle protein metabolism. The interaction of post exercise metabolic processes and increased amino acid availability maximizes the stimulation of muscle protein synthesis and results in even greater muscle anabolism than when dietary amino acids are not present. Hormones, especially insulin and testosterone, have important roles as regulators of muscle protein synthesis and muscle hypertrophy. 

Following exercise, insulin has only a permissive role on muscle protein synthesis, but it appears to inhibit the increase in muscle protein breakdown. 

Ingestion of only small amounts of amino acids, combined with carbohydrates, can transiently increase muscle protein anabolism, but it has yet to be determined if these transient responses translate into an appreciable increase in muscle mass over a prolonged training period.

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The Effect of BCAAs on Exercise Induced Muscle Soreness in Bodybuilders

What exactly are branched chain amino acids (BCAAs)? Yeah,we've all heard about their muscle sparing and/or muscle building properties. However, a recent study done in the UK showed that BCAAs can also curb soreness that is often associated with exercise.

The study used a small sampling of twelve males and provided them with either a dose of 10 grams of BCAAs twice daily or a placebo which was nothing more than an artificial sweetener before and following resistance exercise that creates muscle damage. The BCAA supplement was comprised of a ratio of 2:1:1 leucine, isoleucine, and valine, respectively. This ratio is quite standard in many BCAA supplements in the industry. In addition to this initial dose, after an overnight fast, participants who took the BCAAs were given a 20 gram bolus dose, one hour prior to, and one hour after exercise.

The exercise that resulted in EIMD (Exercise Induced Muscle Damage) in this study was 100 drop jumps from a height of 0.6 meters, and a 90° squat. The results showed the group that was administered BCAAs experienced reduced recovery time. Consequently, this group experienced much less soreness than that of the placebo group.

This study demonstrates that it is likely the BCAAs resulted in better protein synthesis and played an important role in reducing the amount of secondary muscle damage in bodybuilders that often accompanies strenuous resistance exercise. BCAAs are an important supplement to invest in if you are looking to build muscle or reduce recovery time after a hard training session.

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