Friday, June 6, 2008

Research Review: Protein Synthesis Part I

Here are some cool, cutting edge studies below on protein synthesis for you!

A few key points to remember

  • Ideally, a study would measure protein increases (fractional synthesis rate, increase in lean body mass, etc) or what is referred to as an anabolic process (which means "building stuff" and this stuff can be muscle, fat, bone, etc) AND protein break down referred to as a catabolic process ("breaking down stuff"). The balance will hopefully be positive (if we are talking protein, bone, but not fat!)
  • Similar to your checking account. If you only look at the money coming in you are only seeing half of it!

In a perfect world, we would know how much muscle/strength was added (performance effect)

  • Creatine kinase (CK) and other items are used to look at muscle breakdown/injury. Some injury is needed for growth (how much, when, for how long, no one really knows) but we really want to look at body composition and performance changes. Incidentally, even though CK is measured is lots of studies, is it very poorly correlated to performance changes.

Protein/carbohydrate timing is a whole book on to its self. A few key points to look for are:

  • Fasting or in a fed state? Most athletes will be in a fed state prior to training
  • Training stimulus? Aerobic (running), or Anaerobic (weight training) or something in-between?
  • How long did they look? 30 min? 48 hrs? Some literature suggests that a response from weight training may last at least 48 hours or even longer!

Here you go! Part II will be out tomorrow with some conclusions. ACSM updates will be coming soon
Any questions, thoughts let me know
Mike N

The effects of the 5-HT2C agonist m-chlorophenylpiperazine on elite athletes suffering from unexplained underperformance syndrome (overtraining)

Conclusion: “The study suggests that this adaptation may be lost in athletes with UUPS (unexplained, underperformance syndrome): this might explain some of their observed symptoms.”

Effect of a Pre-Exercise Energy Supplement on the Acute Hormonal Response to Resistance Exercise

Conclusion: “The enhanced exercise performance resulted in a significantly greater increase in both growth hormone and insulin concentrations, indicating an augmented anabolic hormone response to this pre-exercise S.”

Co-ingestion of leucine with protein does not further augment post-exercise muscle protein synthesis rates in elderly men

Conclusion: “Co-ingestion of leucine with carbohydrate and protein following physical activity does not further elevate muscle protein fractional synthetic rate in elderly men when ample protein is ingested.”

Leucine-enriched essential amino acid and carbohydrate ingestion following resistance exercise enhances mTOR signaling and protein synthesis in human muscle

Conclusion: “The data suggest that enhanced activation of the mTOR (mammalian target of rapamycin) signaling pathway is playing a role in the greater synthesis of muscle proteins when resistance exercise is followed by EAA+CHO (Essential Amino Acids + Carbohydrates) ingestion.”

Amino acid metabolism and regulatory effects in aging.

Conclusion: “Muscle loss with aging is associated with significant changes in amino acid metabolism, which can be acutely reversed using nutritional manipulations and exercise. Long-term, large clinical trials are, however, needed to determine the clinical significance of these findings in the elderly population, and to establish if nutritional and exercise interventions can help prevent and treat sarcopenia.”

Branched-chain amino acid supplementation and indicators of muscle damage after endurance exercise.

Conclusion: “The data suggest that BCAA (branched-chain amino acid) supplementation attenuates muscle damage during prolonged endurance exercise in untrained college-age men. CHO (Carbohydrates) ingestion attenuates CK (Creatine kinase) activities at 24 and 48 h postexercise as compared with a placebo beverage.”

Exercise- and nutrient-controlled mechanisms involved in maintenance of the musculoskeletal mass.

Conclusion: “Exercise not only stimulates protein synthesis in muscle, but also in tendon; and disuse atrophy is accompanied by marked decreases of both muscle and tendon collagen protein synthesis. Bone collagen synthesis appears to be nutritionally regulated by the availability of amino acids, but not lipid or glucose.”