Anabolic The

Window Is It A Myth?

By Aidan Goggins BPharm, MSc Nutr Med, MPSI

is primed for growth as long as a suitable protein source is consumed. With just a small window of opportunity to provide this protein source to your muscles, supplement companies have gleefully pointed out the benefit and convenience of the rapidly digested whey protein shake.

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This begs the question, is there merit to such a claim or is it yet another example of an overhyped marketing ploy?

The Case For The Post Workout Window It is well established that a higher than average protein intake is necessary to reap the full extent of benefits from resistance training. Dietary protein is a must for achieving positive nitrogen balance post training; enhancing post-exercise muscle protein synthesis and inhibiting muscle protein breakdown (1-3). This allows increased muscle protein accretion during the post-exercise recovery period. Academic consensus is that strength and power athletes require at least twice the protein intake of sedentary individuals (4), and a recent meta analysis found significant augmentation of the adaptive response of our muscles (increased skeletal muscle mass and strength) when weight training individuals, already habitually consuming 90-100g of protein daily (the British Dietetic Association recommends levels of 55 grams a day), upped their daily protein intake by 50 grams (5).

Anabolism is raised for 48 hours post exercise, but it is not at a steady rate – with a 112% increase observed after three hours, dropping to 65% at 24 hrs and 34% at 48hrs (6). Along with this the post-exercise increased blood flow to the worked muscles will likely enhance amino acid uptake, as well as the possible effect of anabolic priming from altered hormonal mediators (7).

he concept of the post-exercise ‘anabolic window’ has become so ingrained in the resistance training community that it is practically dogmatic. It refers to a limited time period where, post resistance training, skeletal muscle

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The REPs Journal 2013;27(May):12-13