Differences in Growth Hormone, Insulin and IGF-1 Response in Trained and Untrained Resistance Trainees - Further Evidence That GH Builds Neither Muscle Nor Strength

Image 1: Rookie (top) or veteran (bottom, Jack Lalanne), their hormonal response to push-ups is different, but does not explain the different outcomes of strength training.

If you are a regular, here at the SuppVersity, you will have hear me lament the fact that in many of the mainstream studies on the effects of exercise on body composition, endocrine parameters and so on, the study participants are either sickly, obese or both... admittedly, whenever measures of muscle hypertrophy are involved, the subjects are usually healthy rookies, which is by  no means better, as you all know from your first weeks in the gym that, despite doing everything wrong, your strength and size gains were tremendous. Now, the obvious question is, are the endocrine adaptations / responses distinct, as well? According to the results of a recent study by Rasani Ranjbar et al. they are (Hasani-Ranjbar. 2011) - surprisingly, though, on paper, the endocrine milieu of the veterans appears more conducive to strength and size gains than that of the rookies... but let's take a look at the actual results, before we even start discussing their implications.

The Iranian scientists recruited 15 previously strength trained and 19 untrained male (how else could it be in this lovely country?) students at the Tarbiat Moallem University, divided them in an experimental (trained) and a control group and took blood samples at 10am (pre-test) after the students, who had arrived at the lab at 7am, had been served identical breakfasts (at 7:30-8:00am). Subsequently, the training groups (E1 = previous strength training experience; E2 = rookies) performed a resistance training protocol at 70-80% of their maximum strength in the 10-12rep range (i.e. a classical "hypertrophy training"), consisting of 4 sets of chest presses, stretch wires [I have no clue what kind of Iranian specialty that is], leg extensions and leg curls to failure with rest times of 2 minutes in between sets and 4 minutes between exercises.

Figure 1: Training induced changes in growth hormone (GH) compared to untrained control (Hasani-Ranjbar. 2011).

Blood was drawn at four timepoints: pre-test (T1), immediately after cessation of the exercise session and before lunch was served (T2), five hours post training (T3) and seven hours post training (T3). The samples were analyzed for growth hormone (GH), insulin, insulin-like-growth-factor 1 (IGF1), IGF1 binding protein 1 and 3 (IGFBP1 & IGFBP2). I have plotted the relevant data (i.e. data where you see meaningful changes) in figures 1 & 2.

Figure 2: Training induced changes in insulin and IGF1 compared to untrained control (Hasani-Ranjbar. 2011).

Now, what do we make of these results? Obviously the immediate GH response to resistance training is more profound in the veteran group, it is yet more sustained in the rookies, whose insulin levels interestingly skyrocket in the late post exercise period, yet in the absence of any significant increases in IGF1 levels (the same was true for the binding proteins) over the untrained control group.

Figure 1: Absolute IGF1 levels (in ng/ml) in trained and untrained rookies and veterans (Hasani-Ranjbar. 2011).

I don't know which data the Iranian scientists analyzed, but despite the fact that there is as they state a steady decline in IGF1 this probably isn't a result of the strength training regimen (as the Iranians would have it) but simply related to the lack of food intake in the 5-7h post lunch, which was ingested right after the post blood draw, i.e. exactly 5 hours before the 5h post blood was drawn....

Be that as it may, the more relevant result is that there may be differences in the endocrine response to exercise, but those are exactly contrary to what we would have to see, if the highly marketable GH increase, you are supposed to spike with all sorts of supplements had any effect on your gains in the gym. After all, you bet that if any of the two groups had had measurable strength or size increases at a subsequent training session / body composition measurement, it would have been the rookie group. That being said, this study further supports the position of the Phillips group from McMaster University (cf. Arms Don't Grow Faster with Prior Leg Training), who maintain that the exercise induced GH increase has absolutely no effect on strength or size gains... in other words, spending money on respective supps or focusing on training techniques that have been shown to increase GH (and have not been shown to be productive in terms of size and strength gains) is not advisable.

"20g or 40g of Whey?" That's the Wrong Question, When 4-5x 20-25g from Different Sources Would be the Answer!

Image 1: There could be a reason that your favorite protein powder comes with a scoop and a suggested serving size of 25-30g protein (max.)

If you could just pick one dietary supplement to take to desert island, what would it be? Creatine? Unquestionably a good choice. Yet even if the local fauna provided you with unlimited amounts of eggs, meats and fish, a whey protein powder, or I should say a leucine-rich complete protein source would probably be a better choice. Despite the fact that I am still skeptical as far as the real world significance of supplementally augmented post-exercise increases in fractional protein synthesis as the main, let alone exclusive determinant of skeletal muscle hypertrophy is concerned, it is undebatable that the delicate balance between protein breakdown and synthesis is at least the most obvious and, in the short term, probably in fact the most influential contributor to muscle growth.

"Only 1.2 - 1.6 protein per kg/day!?" - Calm down! The total amount is not all that counts

According to the latest installment of the "A to Z of Nutritional Supplements" series in the British Journal of Sports Medicine (the part on protein was - you may already have guessed it - co-authored by no one else but Stuart Phillips) the "current scientific evidence" suggests that

1. daily intakes higher than the RDA, to be precise, 1.2-1.6g/kg body weight,
2. an emphasis on leucine-rich protein sources (I suggest dairy, alternatively pea protein),
3. multiple servings of 20-25g of protein / protein-rich foods spread equally across the day,
4. an additional protein shake immediately after your workout

"should be very effective at allowing repair, remodelling and adaptation, and gains in lean mass in athletes" (Phillips. 2012).

Quality, Consistency and frequency over gluttony

For an 80kg athlete this would translate into a total protein intake of 96-128g of protein per day. Sounds pretty sparse, right? Well, if we just count proteins from meats, eggs, fish, dairy and dietary supplements and discard the protein from other sources, this would leave our 80kg athlete with max. 4-5 meals at which he would easily achieve the "threshold" limit of 25g; five opportunities to monetize on the dietary induced increase in protein synthesis; and five potentially protein anabolic spikes in plasma amino acid concentrations.

Remember: In the slowly abating hoopla around leucine people tend to overlook that despite its ability to set the protein synthetic machinery into gear, leucine needs the other EAAs and conditionally essential amino acids to get its muscle building job done.

And though the actual data does not provide any revolutionary new insights into the "ideal" amount of protein, a recently published study from Kevin D. Tiptons group at the University of Birmingham provides further evidence that everyone who strives to maximize skeletal muscle protein synthesis should be primarily concerned about the consistent and frequent (3) ingestion of quality (2) protein (Jackman. 2012).

Figure 1: Urea production (µmol/h/kg * 4h) and fractional myofibrillar protein synthesis (per hour) in the 4-hour recovery period after an intense leg workout and supplementation with either 20g or 40g of whey protein (data based on Jackman. 2012)

Despite the fact that there was a greater increase in fractional myofibrillar protein synthesis after the ingestion of 40g vs. 20g of whey protein after the 8 sets of 10 repetitions of leg presses and leg extensions the 30 previously resistance trained male subjects in the Jackman study had to perform, the +10% difference (+51% increase in MPS in the WP40, +41% in the WP20 group; increase expressed vs. placebo), the latter did not reach statistical significance over the 4h post workout period.

Diminishing returns with large vs. multiple bolus ingestions

Contrary to previous studies investigating the differential response to different amounts of dietary protein in the vicinity of a strength workout (cf. "Protein Synthesis Beyond the 20g Limit"), in which the subjects often trained in a fasted state, the Jackman study also confirms that the profound beneficial effects of immediate protein supplementation are retained, even if the last "protein rich meal" was consumed "only" 3h before the workout.

Figure 2: Experimental protocol of the Jackman study (based on Jackman. 2012)

This beneficial effect of repeated protein ingestion / protein timing stands in line with with the observation that Jackman et al. observed peak amino acid concentrations in the WP20 and WP40 arm of their study 15-30min and 45-60min after the ingestion of the respective amount of whey protein. From the fact that the latter went hand in hand with a statistically significant increase in insulin concentrations and +25% greater urea production in the WP40 trial, we can assume that a non-significant amount of the additional 20g of protein of the 40g whey protein shake was "abused" for gluconeogenesis instead of getting stored within the muscle tissue.

Image 2: The results Adelfo saw from the consistent intake of a perfectly timed mixture of fast and slow digesting proteins speak for themselves - intermittent fasting or not, consistency and frequency are key!

So, even if you don't care about "wasting" dietary protein, you better make sure to distribute your protein intake evenly within your "feeding window", with 20-25g of fast-digesting protein like whey every 2-3h, or a combination of fast digesting and slow digesting proteins (like whey + casein, or whey alone followed by a complete meal) every 3-4h to maintain a decently high and thusly "pro anabolic" level of amino acids in your blood stream while avoiding the hyperinsulinemic effects of larger boluses of whey protein. And if you don't think that this will work, or would be incompatible with the Intermittent Fasting protocol you have taken up as of late, I suggest you go through Adelfo Cerame's contest prep diet again, because with the lions share of his protein intake coming from very slow digesting "real food" protein sources (specifically meats and casein from cottage cheese and raw milk, cf. "3.2kg of Lean Mass With 40g of Casein Pre-Bed"), he strategically spiked with whey protein in the vicinity of his workouts - Adelfo achieved just that: a decent level of hyperaminoacidemia (=elevated serum amino acids) to make optimal use of the "24h Barn Door of Opportunity".