There is Such a Thing As Overtraining, Beware! When IGF-1, MyoD & Myogenin Plummet and MAFbx Gnaws Away Your Muscles, It'll Already be Too Late to Acknowledge

Overtraining is real and it's blocking future and reversing past gains.
I am well aware that somewhere out there in the broscientific spheres of the pseudo-experts on the various bulletin boards of a world people call the Internet statements like "there is no overtraining, just undereating" are not uncommon. And in fact, there is a certain connection between the effects / symptoms we usually associate with overtraining on the one, and the consequences of undereating on the other hand. It's a perfect synergy, if you will - a synergy I have been writing about in the past (suggested read: "The SuppVersity Athletes' Triad Series" | read more), but it's not what the most recent study from the Sao Paulo State University in Brazil is about (Alves Souza. 2014).

Overtraining comes in two forms

If this is not your first visit to the SuppVersity the phrases "sympathetic" and "parasympathetic" overtraining will probably sound vaguely familiar. While the latter is the form of overtraining that develops after weeks of 2-4h of daily cardio-training - usually in the presence of undereating, the former is supposed to occur after heavy lifting sessions and is thus more common in sprint type sports.
Check your training status with a heart rate monitor: In spite of the fact that there is no 100% reliable method to test, whether you're overtraining, the heart rate variability - or rather the way it's changing in the course of a training cycle can give you a good idea of whether you're doing too much, already (learn more in "Are You Overtraining? Two Scientifically Proven Methods to Test Yourself" | Part I, Part II).
In the early phases sympathetic overtraining may feel like being "overstimmed", i.e. similar to the strange agitated weakness caffeine naive individuals may experience after their fourth cup of coffee. That's before a deliberating fatigue will take over, episodes of hypoglycemia during (and after) exercise will occur and your life will start to suck as much as your performance (yes, depression is another symptom of overtraining).

Muscle loss instead of gains

While performance oriented athletes usually pull the emergency break, when the notice that their strength, speed, agility, dexterity and all the other qualities that are relevant for world-class performance decline, Mr. Average Joe and his wife Jane tend to ignore the signs until it's already too late and the hormonal changes, Alvez Souza et al. observed in their latest study have already started to gnaw on their precious muscle mass.
Figure 1: Expression of hyptrophy relevant protein and hormones after 12 weeks of (over-)training, as well as subsequent effects on cross-sectional area (CSA) of plantaris muscle; trained vs. sedentary animals (Alves Souza. 2014)
What you can see in Figure 1 are the consequences of 12 weeks of training, in the course of which, the labrats of the Brazilian researchers were subjected to a 1training program with excessive training
load and insufficient recovery time between bouts using a water jump-exercise model of squatting (Figure 1, right):
"Briefly, rats underwent to consecutive training sessions (5 day/week) that consisted of jumps (repetitions) to the water surface (38 cm deep; approximately 150% of rat body length), carrying an overload strapped to a vest on the animal's chest. Initially, all animals completed a 1-week pretraining (once daily) that consisted of a progressive number of sets (2-4) and repetitions (5-12) with a 30-s rest between each set, and carrying an overload of  50%  body  weight  (BW).  Subsequently,  the  rats  began  the  12-week  training  program,  which consisted of progressive overload corresponding to  60% (1 to 3 week), 65% (4 to 6 week), 70% (7th to 8th week), 80% (9th to 10th week), and 85% (11th to 12th week) of BW." (Alves Souza. 2014)
As Alves Souza et al. point out, they have previously demonstrated that this training protocol is effective in promoting type IIA and IID  fiber  atrophy  in  rat  plantaris  muscle  - as long as it is done in a sane and not the typically Western "more helps more" way that was applied in the study at hand.
Overtraining leads to significant changes in muscle specific hormones and proteins: If you discard the fact that most gymbros don't train legs at all (you know, they play football or soccer, right ;-) the above looks pretty much like the "5-days a week, why don't I grow" regimen of the average self-proclaimed hardgainer, whose consternation about his lack of gains is hardly surprising in view of ...
  • When it comes to IGF-1 looking at systemic levels is not enough - rather than the circulating "full" version of MGF, it's the presence of its local splive-variants like MGF that's actually igniting muscle growth. You can learn more about MGF and other factors that contribute to muscle growth in the "Intermittent Thoughts on Building Muscle" Series | go ahead!
    the upregulation of MAFbx, a muscle protein and that is released if you bath muscles in petri dishes full of glucocorticoids has emerged as a central regulator of skeletal muscle catabolism in previous studies (6, 13, 34),
  • the reduction in MyoD and myogenin and the consequent inability to compensate for the exercise induced damages (let alone build new muscle) due to the lack of satellite cell (=muscle stem cell | learn more) activity,
  • the drop in IGF-1 and it's local splice variants that decline with decreasing systemic levels of IGF-1 and play an (imho) still largely underestimated role in the concert of skeletal muscle hypertrophy (see "IGF-1 and its Splice Variants MGF, IGF-IEa & Co - Master Regulators or a Bunch of Cogs in the Wheel of Muscle Hypertrophy?" | read more)
Although we may still be light-years away from understanding the exact interplay of all these factors, I can tell you one thing for sure: As productive as a short 2-week phase of overreaching may be - don't be fooled to believe that the gains would keep coming if you just kept pushing.
  • Alves Souza et al. "Resistance Training With Excessive Training Load and Insufficient Recovery Alters Skeletal Muscle Mass-Related Protein Expression." Journal of Strength and Conditioning Research (2014). Publish Ahead of Print
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