The skeletal muscle is a highly plastic tissue that can adapt to increasing exercise demands. The extent of adaptation depends on the activity performed and the individual’s genetic makeup. This adaptative specificity reflects heterogeneity in response to different exercise training regimens. The amount of muscle protein that responds to exercise is an important determinant of skeletal muscle responsiveness.
Increases in muscle protein synthesis after a meal containing amino acids
In a recent study, researchers found that a meal rich in amino acids increases muscle protein synthesis in older men. However, exogenous insulin did not increase the rate of muscle protein synthesis when administered systemically. The authors of the study, Tran L, Hoffman N, Kras KA, and Smeuninx B, concluded that the protein-building benefits of amino acids are not due to increased protein synthesis in humans, but rather to increased muscle protein turnover and protein contractile function.
Moreover, muscle protein synthetic response is likely to be influenced by habitual nutrient intake and other nondietary factors. Therefore, nutritional recommendations should be tailored to the 단백질 보충제 needs of individual athletes. In addition, an athlete should consider his or her physical activity level and the type of meal he or she is consuming. This way, the nutrient intake should be balanced in order to maximize muscle protein synthesis.
The researchers concluded that eating a meal rich in amino acids before exercise significantly increased muscle protein synthesis after resistance training. They also observed that fluid skim milk boosted muscle protein accretion after resistance exercise. Further, they noted that amino acids promote the metabolic effect of exercise on muscle protein synthesis.
Several reports have examined the effects of different protein sources on muscle protein synthesis and mTOR signalling. Results of these studies have indicated that leucine-rich whey protein stimulates muscle protein synthesis more than other sources of protein. However, limited data are available on the effect of whey protein hydrolysates.
Relationship between muscle protein synthesis and muscle mass gains
Research has shown a link between muscle protein synthesis and muscle mass gains. However, this relationship is not clear-cut. While mTOR is a factor in muscle protein synthesis, mTOR alone does not necessarily predict muscle mass gains. Moreover, a study measuring muscle protein synthesis over a single training session does not capture the full response to resistance exercise. Therefore, it is difficult to draw definitive conclusions based on this data.
There is a link between higher training volume and higher muscle protein synthesis rates. Research shows that resistance training with multiple sets stimulates muscle protein synthesis more effectively than single sets. Also, a single bout of resistance exercise can stimulate muscle protein synthesis for up to 72 hours. A popular training strategy is the so-called ‘bro-split’, whereby a single training session hits each muscle group once a week, but on different days of the week.
Similarly, muscle protein synthesis and muscle mass gains were correlated in untrained subjects. The study showed that during the first three weeks of an exercise program, muscle protein synthesis increased substantially. After three weeks, muscle protein synthesis was mainly used for the repair of damaged muscle proteins.
Muscle protein synthesis is crucial for maintaining the health of skeletal muscle. Without muscle activity, human skeletal muscle will never grow larger or stronger. Muscle protein synthesis is the key to constructing new muscle cells. It also helps the body maintain existing muscle tissue.
Effects of protein timing on muscle protein synthesis
While it is possible that protein timing can have beneficial effects on muscle protein synthesis, there are many questions to be answered before concluding that timing is important. In particular, it is unclear whether timing is related to the total amount of protein consumed or the intensity of training. To date, there are only four studies addressing this question. A meta-analysis is needed to evaluate the effects of protein timing on muscle hypertrophy and strength.
Several studies have suggested that immediate protein intake may not be beneficial for muscle hypertrophy. However, other studies have shown that peri-workout protein intake has positive effects on muscle hypertrophy. However, the majority of these studies did not include controls for protein intake, which makes it difficult to draw firm conclusions.
Regardless of timing, the best way to optimize muscle protein synthesis is to eat the right amount of protein during the right period. The optimal amount of protein to consume before exercise is 1.6 g/kg. Aim for this amount of protein if your training is longer than 6 hours.
Post-exercise protein synthesis is boosted after intense exercise, but short rest periods reduce post-exercise muscle protein synthesis rates. Studies show that a single bout of resistance exercise may stimulate muscle protein synthesis for up to 72 hours. However, the rate of synthesis peaks at 24 hours after a single bout of resistance exercise.