Thursday, March 21, 2013

Greater Strength Without Compromised Size Gains With Rest-Pause. Can Dietary Variety Fight or Cause Obesity? Catabolism & Anabolism Just 2 Sides of the Same Coin. GABA as a GH Promoting Brain Anabolic?

Can't squeeze out another rep? Not a problem have some intra-set rest and continue pumping thereafter.
I guess, I did this before, but I say it again: "Congratulations, Adelfo Cerame Jr.! You are the man." Obviously, we all knew he is, but as of now, even the judges have finally acknowledged that. Reason enough to do a Science Round-Up Special today, in the course of which Carl Lenore and me are going to pick Adelfo's brain and have him surrender all the secrets that made him finally achieve what he has been chasing for years, now: The status of a wheelchair pro bodybuilder.

Just like the regular show the live show will be kicking off at 1PM EST. If you miss it it's not a problem, there is also going to be a special edition of the "Seconds", tomorrow with Adelfo looking back at how the contest went and how he made sure to peak right on time (edit: you can download the podcast now).

And just to make sure that no one complains: I compiled a couple of news as a surrogate for the regular Science Round-Up, today (this was "last minute", so please ignore any typos and grammatical mistakes).  

Rest-pause technique leads to greater strength w/ identical size gains (Oliver. 2012) -- The bad news first, I can't tell you exactly how long the 22 male subjects (25 +/- 5yrs, 179.71 +/- 5.0cm, 82.1 +/- 10.6kg, 13.6 +/- 4.3% fat, 6.5 +/- 4.5yrs training)  Jonathan Oliver recruited for the experiment he wrote his dissertation on actually rested withing (=intra) their sets. Usually you would expect something along the 10 deep breaths - just enough to get your game on, so to say.
Figure 1: 1-RM max and power on bench presses and squats before and after 12 weeks of classic (regular sets) and alternative intra-set rest interval (rest-pause) training in 22 young resistance trainees with >2y of training experience (Oliver. 2012)
You got to remember, though, that I cannot guarantee that the 10 deep breath version of the rest-pause technique will yield the same remarkable results you see in figure 1 until the embargo on the dissertation falls or a student of the Texas A&M who I believe should be able to peak into the actual full text gives me a hint on the details of the study protocol. In the mean time, take the increased strength gains (check the percentages above the bars in the post columns), as an incentive to (re-)incorporate rest-pause sets where you perform 2-5 reps, rack the weight, pause, pick it up again and perform another 2-5 reps with the same weight and so on until you hit your target rep range, e.g. 12 reps on the bench with 200lbs, where you usually cannot do more than 5, into your routine.

Dietary variety does not protect us from from becoming fat (Vadiveloo. 2013) -- In a soon-to-be-published systematic review of epidemiological studies researchers from the Steinhardt School at the New York University report that dietary variety does not protect against obesity. In fact, the exact opposite can be the case if "your variety" is a variety of sugar + fat-laden junk foods. In that case you are even more likely to fall victim to the metabolic syndrome than someone who eats just Twinkies and does not switch to Dingdongs once in a while:
If you are interested in buying quality, you may want to revisit the post on pesticide residues in organic and regular produce (go back)
"The present review is an important first step in clarifying the associations between dietary variety and excess adiposity, which is currently limited by the methods used to assess variety.

In the present review, we found that (1) dietary variety within recommended and low-energy foods alone do not increase the odds of overweight and obesity, (2) greater variety within less healthful, energy-dense foods increases the odds of overweight and obesity and (3) the association between total dietary variety and adiposity is mixed and accurate evaluation of this association requires a consistent and theoretically valid measurement tool."
This is, allegedly not a really surprising finding, what may yet surprise you is that the scientists didn't find a positive association for a variety of healthy foods in the diet, either. Sounds like quality and quantity, but not diversity remain what determines our likelihood of becoming obese... but let's be honest, isn't eating - at least from time to time - so much more than just providing your body with the nutrients it needs?

There is no protein synthesis without catabolism (Bentzinger. 2013) -- A very intriguing study that's about to be published in the next issue of Skeletal Muscle found that the constant and isolated expression of MTOR-1C in a rodent model leads to profound muscle catabolism and not as you may have expected exuberant muscle growth. The underlying reasons for this counter-intuitive effects are the m-TOR induced blockade of the p-AKT pathway which is also responsible of keeping the catabolic MuRF1 pathway in check:
The AMPK-mTOR seesaw
"Our study shows that the mTORC1- and the PKB/Akt-FoxO pathways are tightly interconnected and differentially regulated depending on the muscle type. These results indicate that long-term activation of the mTORC1 signaling axis is not a therapeutic option to promote muscle growth because of its strong feedback induction of the E3 ubiquitin ligases involved in protein degradation."
In view of the fact that few of you will be mutants with a constant (over-)expression of mTOR-1C the scientists most recent observation does actually have implications for you as a trainee. It does not only re-emphasize the importance of the cyclic nature and tight inter-regulation of protein synthesis and degradation, but should also remind you no to rely too heavily on studies measuring only increases in protein synthesis without accounting for the net protein retention.

GABA exerts indirect "anabolic" effects on the brain (Thanapreedawat. 2013) -- In yet another advanced publication that happens to overlap with the sudden re-appearance of GABA supplementation within the health and fitness community, Thanapreedawat and colleagues report that the administration of gamma-amino-butyric in the drinking water (0.5% and 1.0%) of young rats lead to highly significant activation of the intra-cerebral mTOR pathway, a subsequent dose-dependent increase in S6K1 phosphorylation and corresponding increases in brain protein synthesis.
Figure 2: Relative changes (compared to control) in insulin, insulin-like growth factor (IGF-1) and growth hormone (GH) in response to 0.5% or 1.0% GABA in the drinking water of 3-week old Wistar rats (Thanapreedawat. 2013)
Now what's really interesting about the study is that these effects were not mediated centrally. In other words, the orally ingested GABA did not pass the blood brain barrier. That this was possible is sometimes touted by producers of respective supplements. Previous studies have yet conclusively shown that orally ingested GABA does not make it across an intact blood brain barrier in vivo, so that any effects GABA may have must originate in the periphery  and that's actually what the scientists believe happened here, as well.

The peripheral effects of the orally administered GABA, namely the pronounced increase in growth hormone (GH) (cf. figure 2), a molecule which has previously been shown to be able to cross the blood brain barrier (Bermann. 1994; Ohsumi. 2008) lead to an activation of the intra-cerebral mTOR cascade and the subsequent increase in protein synthesis. If you expand on that, you could even speculate about other GH mediated effect of GABA supplementation... I must yet forewarn you: GABA is not a proven ergogenic of any kind (doesn't build muscle, doesn't make you lean, etc.).

Usually this would be the place to add some references to the latest Facebook news, but since the show is about to start in a couple of minutes (listen live), I'll just refer you directly to the SuppVersity Facebook Wall. With 6-9 studies you won't read about anywhere else every day, it's always worth visiting, anyway ;-) 

  • Bentzinger CF, Lin S, Romanino K, Castets P, Guridi M, Summermatter S, Handschin C, Tintignac LA, Hall MN, Rüegg MA. Differential response of skeletal muscles to mTORC1 signaling during atrophy and hypertrophy. Skelet Muscle. 2013 Mar 6;3(1):6.
  • Bermann M, Jaffe CA, Tsai W, DeMott-Friberg R, Barkan AL. Negative feedback regulation of pulsatile growth hormone secretion by insulin-like growth factor I. Involvement of hypothalamic somatostatin. J Clin Invest. 1994 Jul;94(1):138-45.
  • Ohsumi M, Tujioka K, Hayase K, Nagata S, Yokogoshi H. The growth hormone affects the brain protein synthesis rate in hypophysectomized aged rats. J Nutr Sci Vitaminol (Tokyo). 2008 Feb;54(1):76-81.
  • Oliver J. Intra-Set Rest Intervals in Hypertrophic Training: Effects on Hypertrophy, Strength, Power, and Myosin Heavy Chain Composition.Doctoral dissertation, Texas A&M University. 2012.
  • Thanapreedawat P, Ohsumi M, Hayase K, Yoshizawa F, Yokogoshi H. Influence of GABA on Brain Protein Synthesis Mediated by the Mammalian Target on the Rapamycin Pathway. Biosci Biotechnol Biochem. 2013 Mar 7.
  • Vadiveloo M, Dixon LB, Parekh N. Associations between dietary variety and measures of body adiposity: a systematic review of epidemiological studies. Br J Nutr. 2013 Feb 27:1-16.