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05.03.2014

Stretch 'n' steroid combination produces muscle growth

Imagine: an injury means you can't train for a while, but you can use anabolic steroids. In this hypothetical situation you can maintain more muscle mass by doing stretch exercises. You may even be able to build up a little bit of muscle mass, according to an animal study that sports scientists published in Scientific World Journal.

The researchers, who work at Kagoshima University in Japan, gave rats methenolone [an anabolic steroid, structural formula shown above] in a dose of 20 mg/kg bodyweight. The human equivalent of this dose is about 200-300 mg. The researchers injected the steroid directly into the small intestine.

A control group was given no methenolone.

The rats were sedated, which meant that the researchers could stretch the animals' right-hand gastrocnemius muscle. They did this 15 times a minute for 15 consecutive minutes. The researchers did nothing with the left-hand gastrocnemius.

Twenty-four hours later the Japanese observed that the combination of stretches and the anabolic steroid had boosted the synthesis of Mechano Growth Factor [MGF]. Mechano Growth Factor is a stripped down version of IGF-1 [structural formula shown above]. Fundamental research has shown that the anabolic effect of MGF is so strong that the researchers are convinced that the combination brings about muscle growth.

White bars: cells from muscles that were not stretched; black bars: cells from muscles that were stretched.

The researchers also looked at the synthesis of the anabolic signal proteins Myo-D and myogenin, but found no effect.

"Mechanical stimulation of skeletal muscle in conjunction with the administration of an anabolic steroid induced mRNA expression of MGF", the researchers conclude. "This finding suggests that the combination of anabolic steroids with muscle stretching exercise could promote muscle strengthening in patients with muscle weakness."

The reason that the researchers don't attach so much importance to the absence of an effect of the stretch-methenolone combination on Myo-D and myogenin is probably to be found in an animal study they published earlier, in May 2013. [ScientificWorldJournal. 2013 May 23;2013:493656.]

In that study the researchers used no steroids. In one group of experimental animals the researchers kept the right gastrocnemius muscle stretched for 15 minutes [SSC] and did nothing with the left gastrocnemius [USC].

In another group of rats the researchers stretched the right gastrocnemius 15 times a minute for a period of 15 minutes [SSR], and did nothing with the left gastrocnemius [USR]. This is also the protocol that the researchers used in the experiments when they gave the rats methenolone.

At the end of the week the researchers observed an increased synthesis of Myo-D [first figure below] and myogenin [second figure] in the SSR group. Apparently muscle cells subjected to stretching need longer than a day to boost the production of Myo-D and myogenin.

"In conclusion, passive stretching for a short duration once daily at several days within a 1-week period is effective in the growth of the skeletal muscle", the researchers conclude in the older study. "Repetitive stretching is suggested to have greater effects than continuous stretching. These findings suggest that passive stretching is useful in the prevention and maintenance of skeletal muscle tone in patients who are unconscious or paralyzed."

Source:
ScientificWorldJournal. 2013 Aug 25;2013:313605.

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Stretching the right calf muscle makes both calves stronger 16.04.2012
Combine strength training with stretching and you'll get stronger 29.03.2010
Stretching between sprints better than rest 10.02.2010