Bodybuilding - The Principles Behind Muscle Growth

When it comes to bodybuilding, the process of muscle growth can be different depending upon the training program that is utilized.

There are two main ways that muscles will grow: sarcoplasmic hypertrophy and myofibril hypertrophy.

How you train will determine which type of growth you are primarily experiencing.

Sarcoplasmic Hypertrophy

Sarcoplasmic hypertrophy is what is going to mostly make the actual size of your muscle look bigger initially. You've likely experienced this before if you ever put in a really good bicep and tricep workout and noticed your arms looked particularly large. What's going on?

What happened is that there was a build-up of intercellular byproducts (such as lactic acid for example) that caused a so-called 'muscle pump'.

Unfortunately, as you've also probably noticed before, this 'pump' does not last for very long. Within an hour or two after the workout, those byproducts will be removed from the tissue and you'll be back looking more like your usual size.

Not that obviously this type of growth isn't beneficial - a good muscle pump can be highly motivating and keep you coming back to the gym for more, it's just important to understand that this is not going to be long-term growth that's going to stick with you if you stopped working out for a week.

Myofibril Hypertrophy

Next we come to the other type of hypertrophy - the type that's more 'true muscle growth' because it tends to last for months after it's experienced. Myofibril hypertrophy occurs when the actual muscle tissue (also known as the 'myofibril', hence the name) enlarges in response to an overloading stimulus.

These types of gains are a lot slower to be seen and usually won't produce quite the same amount of size as the sarcoplasmic hypertrophy does.

But, the good news is that these gains are also associated with a good increase in strength, thus it's a great indication that you are improving in not only size but also your performance in the gym.

The Best Of Both Worlds

Now, with most training programs you are going to get the best of both worlds just because of the nature of training. First you'll see the sarcoplasmic growth, and then if you carry on with your workout and progressively keep adding weight to the bar then you're going to see the myofibril hypertrophy.

One thing you may want to keep in mind, however, so that you can target your workouts more to what you are going for is that sarcoplasmic hypertrophy will be seen more when your rep range is in the seven to ten range, while myofibril hypertrophy will be effectively targeted with the four to six rep range. The primary reason for this being that to produce a build-up of byproducts you need to work the muscles over a slightly greater period of time, while to work on maximum strength you need to be lifting as high of a weight as possible, so by corollary will be using fewer reps.

So, keep these two main principles in mind during your next workout. Try and work across a variety of rep ranges to experience the best growth possible, growth that not only shows up immediately but then also sticks with you well into the future.