Consuming more and more protein does not result in bigger and bigger muscles. However, timing your protein intake properly can increase muscle tissue synthesis. This fact led researchers at the Metabolism Unit of Shriners Hospitals for Children to conduct a study to determine if the acute anabolic muscle response to resistance training and supplementation with essential amino acids lead to a net increase in muscle protein. Kevin D. Tipton of led the study and writes “Net muscle protein balance has been demonstrated to increase dramatically in response to exercise and amino acid ingestion when measured acutely. However the question remained as to whether this acute response reflected the response of muscle over a longer period of time.” The study is published in the American Journal of Physiology, Endocrinology and Metabolism.
Participants were divided into two groups: 1) rest (the REST group) and 2) rest with resistance exercise and ingestion of essential amino acids pre- and post-exercise (the ES group). The net balance of four amino acids in the leg area, as well as mixed muscle fractional synthesis rate (FSR) were determined after the intervention.
The results showed that, not surprisingly, muscle synthesis was significantly greater for the ES group than the REST group. What the researchers were able to confirm was that the increase in protein synthesis that occurred the ES group resulted in a long-lasting increase in muscle protein for 24 hours, even during the night period when the body usually excretes excess protein. There was no increase in excretion at night even though extra protein had been taken in pre- and post-exercise. Therefore, the supplementation turned out to add to the usual muscle balance, which supports the idea that properly timed protein supplementation can increase muscle protein and muscle tissue synthesis.
The authors write, “Ingestion of the amino acid solution immediately before and 1 hour after exercise improved amino acid exchange when measured both on a 24-hour and 3-hour basis. Thus the acute stimulation of muscle protein by exercise and amino acid ingestion is additive to the balance that normally occurs in resting muscle.”