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Why Some Grow Muscle Easily While Some Don’t?

May 31 2010

The study shows why some folks grow like a weed while other struggle.

The study recruited 66 subjects.The training included 3 sets of squats, Leg Press and Leg Extensions 3 days/week for 16 weeks.

What were the results?

Based on the muscle fiber size, the participants were divided into three groups independent of age or sex ( using new method called cluster analysis):

image

Extreme Responders:  58% increase in muscle fiber size
Moderate Responders: 26% increase in muscle fiber size
Non Responders: 0% increase in muscle fiber size.

What are satellite cells and muscle nuclei?

Before you can understand the results of the study, you need to be familiar with some terms. I will keep it simple and short, promise.

Unlike other cells in the body, muscle cells (or muscle fibers) are multinucleated. Considering how a muscle cell is way larger and complex than the rest of the cells in the body, it makes a lot of sense to have more than one nuclei to control the complex tasks in the muscle.

For instance, if your favorite restaurant was a muscle and the cooks the nuclei, it’s pretty safe to say that the number of cooks sets the limit to the size of the restaurant. Similarly (or somewhat), the size of your muscle is ultimately limited by the number of nuclei you have in your muscle.

Simply put, you cannot grow bigger muscles without additional nuclei to take care of the extra muscle.

So where do we get these nuclei from?

muscle fiber showing nucleus and satellite cells

Figure: A muscle fiber with nuclei shown in blue and satellite cell shown in red.

These muscle nuclei sprouts from specialized cells around the muscle called satellite cells. So any increase in satellite cells means some of these cells could be “blossoming” into new nuclei.

So how did the extreme responders grow muscle easily?

  • The extreme responders had higher satellite cells to begin with. The authors speculate that your muscle growth potential is partly dependent on the availability of satellite cells before training.
  • The satellite cell pool increased a remarkable 117%  in the extreme responders during training.
  • After training, the Extreme responders had significantly more myonuclei per fiber than Non and Moderate groups .

NOTE: It is interesting to note that 1/4(non-responders) of the subjects experienced no growth. The authors speculate that this might be because of a lack of greater recovery period between workouts and/ or additional weeks of training. Studies with 2 days/week has shown better results in older adults.

Practical Recommendations

  • The extreme responders in the study are the genetic freaks who can do whatever and still grow like a weed. So don’t think it is their program as most folks do, and copy it blindly.
  • As far as I know, the only natural way to increase satellite cells is by creatine. Creatine has shown to increase satellite cells substantially compared to training without creatine.

Reference 1

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Boston DUI lawyer | Thu December 16, 2010  

I think that the three levels are influenced by both genetics and external factors. People who are not extreme responders can probably be pushed into that category with extreme stress. Has there been any studies on that?

What do you think?

Smileys

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