|Older Athletes Have Anabolic Resistance|
Amino acids, which are building blocks of proteins, can be essential, non-essential or conditional. Non-essential and conditional amino acids are made in your system. Essential amino acids are found in meat, dairy, eggs, poultry and seafood provide all nine essential amino acids and are known as complete proteins. The Branched Chain Amino Acids (BCAAs) consist of the amino acids, leucine, isoleucine, and valine. The amino acid L-Leucine has shown promise to date, and it is associated with enhanced post-meal consumption protein synthesis. As one gets older, there is blunted muscle growth, and coincidentally there has been documentation of “anabolic resistance.” It has been demonstrated that ingestion of 40 grams essential amino acids (equivalent to ~100 g high-quality protein) lacked the capacity to stimulate muscle protein synthesis rates in the elderly, as opposed to the young. The age-related loss of muscle protein must be attributed to an imbalance between muscle protein synthesis and breakdown rates, resulting in a negative muscle protein balance and, over time, a decline in skeletal muscle mass. This means giving an older adult a dose of protein does not result in the same increases in protein synthesis as a younger adult.
Subjects received one of the following daily:
1. Standard EAA mixture (20% leucine)
2. Modified EAA mixture (40% leucine)
3. Isocaloric placebo (lactose).
Researchers wanted to compare the muscle protein synthesis rates of masters and younger triathletes over three consecutive days of intense endurance training. Recovery of cycling performance, following muscle-damaging running, was also compared between groups. Participants then completed a 30 min downhill run; three 20 km cycling time trials were completed 10, 24 and 48 h following the run. Diet was controlled throughout the study. At the end of the study, over the three days, masters triathletes showed a significantly lower muscle protein synthesis rates compared to the younger. There was also a trend for masters triathletes to produce a slower cycle time trial (-3.0%, d=0.46) compared to younger triathletes at ten hours post-run, in comparison to baseline. The present data show lower muscle protein synthesis rates in well-trained masters triathletes over three days of training, and this likely contributes to poorer muscle protein repair and remodeling. Furthermore, acute recovery of cycle time trial performance tended to be poorer in the masters triathletes. Older athletes can benefit from taking a high quality BCAA powder rich in leucine to help increase muscle protein synthesis and support lean muscle mass.
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