If your going to spend your time and hard earned money on building a bigger, leaner physique, I believe it is important to know not just how and when to do it but why you are doing it too. In order to know why we do specific exercises, amounts of weight, reps and sets we need to know more about muscle growth on a physiological level. In other words, we need to understand how and why the muscles grow. Only then can we be confident with the decisions we make regarding our workouts and our diets.

How do muscles grow?

To put it quite simply, when your muscles grow one of two things is happening. Either the number of muscle cells has increased, known as muscle hyperplasia, or the muscle cells have increased in size, known as muscle hypertrophy.

What causes our muscles to grow?

From the time we are born until our late teen years muscle growth happens naturally. For males, hypertrophy happens an faster rate during puberty.

Hypertrophy can also happen due to strenuous activities causing tears to occur in the muscle fiber. When this happens our bodies will repair damage by adding new muscle tissue, increasing the number and size of myofibrils per muscle fiber, increasing the number of contractile proteins (actin and myosin), and increase the enzymes and stored nutrients within the cells, thus causing the size of the muscle cells to increase.

How can you influence muscle growth in your body?

Ideally, muscle builders want to influence both muscle hypertrophy and hyperplasia. However, it is still uncertain how and if we can influence hyperplasia naturally. The only thing there has been evidence of having an influence on the production of new muscle cells is steroid use, unfortunately. The good news is that we can influence the size of our muscle cells through weight training.

It is a common belief that progressive overload has the most influence on hypertrophy. Progressive overload is essentially a gradual increase in weight, reps, frequency or time. Our muscles will repair and adapt to the stress we put on them, therefor, we need to raise the intensity of our workouts. In other words, doing the same workout over and over will not have a major effect on muscle growth. By adding intensity to your routine on a regular basis your muscles will continually adapt and repair resulting in more and more muscle growth.

It is thought that using 80 to 90% of your one repetition maximum is necessary for muscle growth stimulation. More than 15 reps of an exercise is considered too light to have any effect.

So what does this mean to you?

In order for you to build muscle you need to overload your muscles on a regular basis. Whether you use more weight, do more reps, do more sets, or work out more frequently, it doesn't matter. You just need to make sure that you are working your muscles hard enough to cause the fibers to tear and repair. Otherwise your muscles will adapt to your workout and you will hit a plateau sooner than later. As long as this concept is built into your workout you can be confident that you are on your way to bigger muscles.