|Arnold's workout regimen are known to generate a hell lot of wear and tear and actually this could be part of his success formula.|
Stretch-induced muscle growth
For the rodents in the study at hand the scientists did escalate the dosage and pumped roughly 10mg/kg (this is already the human equivalent) into the critters.
Then, the right gastrocnemius muscles were stretched repeatedly by manual ankle dorsiflexion 15 times per minute for 15 min. The contralateral muscles were not stretched as a control. In the control rats (n=6), the gastrocnemius was stretched as for the treatment group, but no metenolone was injected. Twenty-four hours after the procedure, the rats were sacrificed by injection of a lethal dose of sodium pentobarbital and their medial gastrocnemius muscles removed on both sides.Actually, I suspect the sacrifice would not have been necessary as the extraction of the MGF, or as the scientists call it the "the specific autocrine IGF-I splicing variant mechano-growth factor" is something you can measure from a muscle biopsy. So, the only argument against a human study, is probably the dosage and the general administration of anabolic steroids to human subjects.
|Figure 1: Treatment effects on MGF, MyoD, Myogenin (a.u.) in rats w/w/out metenolone injection (Ikeda. 2013)|
of a mammalian skeletal muscle fiber - myonucleus (turqouis),
mitochondria (blue), sarcoplasmic rectilium (buff), tubules (orange),
myofibrils (pinkish) |
Artist: Lesley Skeates. Originally from Gray's Anatomy 29th ed. Elsevier. 2008
The latter are markers for the often hailed activation, recruitment and replenishment of muscle "stem-", or "satellite cells", of which you know from the Muscle Hypertrophy 101 (read it) that they are what allows you to grow beyond the natural limit, a limit that makes the muscle of myostatin negative animals huge, but dysfunctional - a direct result of the structural changes not being able to keep pace with the constant influx of protein (learn more).
|Figure 2: Illustration of what you should have learned, if you read all installments of the Intermittent Thoughts on Building Muscle (read summary)|
Figure 2, to the right delivers a sneak peak of what you can expect and if that's not attractive enough, I'd suggest you use the "Preliminary Conclusion - Exercise, mTOR/AKT/MAPK, IGF-1, Testosterone, Estrogen, DHT, Nutrition, Supps & Sleep" (read it) of the series as a cognitive anabolic to promote your interest ;-)
I already hinted at that in a previous paragraph, but I think it's still worth repeating in the bottom line that despite being derived in a rodent study with an "exotic" anabolic agent, there is no question that the results of the study at hand will also be relevant for chemical athletes and little evidence they would not apply to
Your reading assignment for today:References:
IGF-1 and its Splice Variants MGF, IGF-IEa & Co
- Are the growths hormones master regulators of muscle growth or just a
bunch of cogs in the wheel of skeletal muscle hypertrophy?
- IGF-1, TNF-α, IL-15 & Co and the Emerging Role of an Auto-/Endocrine-Immune Axis in Skeletal Muscle Hypertrophy - How does inflammation factor in, is it beneficial or detrimental?
Zoning in on "The Big T" - Does testosterone (alone) build muscle?
- Quantifying "The Big T" - Do increases of testosterone, which are well within the physiological range matter?
the "Big T" - How does testosterone work? What is its effect on stem cells and how come it makes you leaner?
Estrogen, Friend or Foe of Skeletal Muscle Hypertrophy?
- Which role does estrogen play and why could you SERM away your growth
potential, when you (ab-)use tamoxifen or potent aromatase inhibitors?
- Dihydrotestosterone (DHT), The All Things Male Hormone - Will it make you bigger, stronger and faster or just balder, fatter and unhealthier?
- Ikeda S, Yoshida A, Matayoshi S, Tanaka N. Repetitive stretch induces c-fos and myogenin mRNA within several hours in skeletal muscle removed from rats. Arch Phys Med Rehabil. 2003 Mar;84(3):419-23.
- Ikeda S et al. The Effect of Anabolic Steroid Administration on Passive Stretching-Induced Expression of Mechano-Growth Factor in Skeletal Muscle. The Scientific World Journal. 2013: Article ID 313605.