How Do Muscles Grow? – Part 5

gainmuscle_1If you would be so kind as to permit me to recap our progress to date I would be ever so grateful. In Part One we looked at the processes that occur during training that influence muscle growth and the recovery mechanisms that our body uses to begin the process of repair. In Part Two we focused on the breakdown process of the damaged muscle and the process of muscle growth including looking at some of the growth factors our body uses to complete this process. In Part Three we talked about those growth factors in a lot more detail and learned how things like testosterone and IGF-1 directly influence muscle building. In Part Four we discussed the reasons why our muscles grow or don’t grow and looked at some of the factors that can help encourage muscle-building. In today’s article I’d like to discuss even more factors that govern growth and like in the four previous articles, use this information to see how we all can benefit in our quest for more muscle.

In every case of weight training there will be endurance adaptations of the type IIB muscle fibers regardless of the rep range. Weight lifting is repetitive in nature and our body will adapt to this by building the energy systems to allow this type of activity to continue. When the load is lighter the adaptations happen both quickly and to a large degree. This is because with a lighter load the type IIB fibers do not have to twitch at a maximum frequency (muscle fibers are either fast or slow twitch, and they do just that) tumblr_mcubdz8pNY1roh2q4o1_1280and instead twitch at a lower threshold for longer periods of time. This physical adaptation will allow the type IIB fibers to produce tension for longer durations and this in turn will produce larger amounts of muscle damage and this will result in a greater growth potential. The rep range that is ideal for this is between 8 and 15 reps, and for this reason bodybuilders favor this rep range.

What also occurs apart from greater muscle damage resulting in greater muscle growth is that the type IIB fibers develop better endurance characteristics related to energy production, meaning higher mitochondrial densities and the ability to sustain enzyme concentrations. Simply put in terms we all understand, this rep range both develops myofibrillar hypertrophy as well as sarcoplasmic hypertrophy simultaneously. Kind of an ideal situation when building muscle is the plan. As we learned in an earlier installment of this series, ATP is needed not only to fuel muscle contractions but also to fuel protein synthesis. Seeing as we are building significant amounts of sarcoplasm that contribute greatly to energy production, we are not only building muscle, but building the potential for muscle also. This is a very important consideration when making a training program.

It would be erroneous to assume that bigger muscles are not stronger muscles, because bigger muscles ARE stronger muscles. The muscle will adapt to whatever is asked of them. If they are being trained in the 8 to 15 rep range then they will develop endurance as mentioned above, but will also develop strength. How much you can lift is still a very important factor to influence muscle growth regardless of the rep range employed. When training in this optimal range, it is still imperative that building strength be the goal. If you workout-tips1-1are just repeating the same lifts week after week after switching to this type of training then you will quickly see your gains come to a halt. It is a fact, a stronger muscle is a bigger muscle and as you build strength, provided that you have the energy systems in place to fuel growth, there will be hypertrophy of the muscle.

Simply put, if building larger muscles is your goal then you have to train with enough resistance that you will be able to stimulate growth, so the weight must be heavy and challenging, but the weight cannot be so great that it won’t allow you train the muscle for long enough to cause the appropriate amount of fatigue necessary to stimulate muscle growth. The rep range that is ideal for this is between 6 and 12. This is generally between 70 to 85 percent of your one rep max. This range will produce the needed micro-trauma to the muscle fibers that will result in muscle growth. If for some reason you are only interested in strength (no one reading this) then sets of 1 to 3 reps at 90 percent of your one rep max is your prescription for progress. This range will allow for your nervous system to recruit muscle fibers more effectively and have them firing all at once to maximize strength. Very little in the way of muscle is stimulated at this rep range.

As mentioned earlier, no matter what rep range you are using or what your goal is you need to focus on building your strength. It is the easiest way to track your progress and it is proof positive that you are progressing. This entire series will serve as a backdrop for next weeks article on functional hypertrophy. Screen-Shot-2011-11-29-at-3.23.56-PMThat is when I will be discussing what Bruce Lee termed as ‘big, useless’ muscle. The kind that doesn’t contribute to anything of value as far as strength is concerned. As much as he knew about physical fitness, he couldn’t have been further off the mark about this. Don’t think I’m knocking Bruce Lee, as that’s like dissing Mr. T – it’s something you just don’t do. I am only using him for context to illustrate that even those very much in the know seem to be mistaken about the relation to muscle size and functional strength. This is all going to be discussed in detail next week. Until then my friends,

Happy Lifting!

Related Reading:

What Happens To Us When We Train?

How To Increase Growth Hormone Levels

Muscle: Anabolic Sleep

This article was researched and written by Matt Taylor

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2 comments for “How Do Muscles Grow? – Part 5

  1. Anonymous
    September 12, 2013 at 10:08 am

    Just read all 5 parts. Gotta do something at work, right? Great series dude.

  2. September 11, 2013 at 11:53 pm

    Super interesting and informational post! I especially liked the part where you explained ATP and said, “ATP is needed not only to fuel muscle contractions but also to fuel protein synthesis.” I had no idea that ATP was so important!

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