Understanding the Muscle: Fibers and Fatigue



So, you’ve decided that you want to get in the gym and build some muscle – that’s great! This guide will dive into the world of muscle-building, tacking it from all angles, so that you can truly understand and appreciate everything that is muscle-building.

The Basics of Muscle

Before we begin our journey towards building quality muscle mass, let’s first lay down the basics on what a muscle is, how it works, and why we want to build muscle in the first place. This post will be technical, so strap yourself in and prepare to get your learn on.

A muscle is by definition a band or bundle of fibrous tissue in the body that has the ability to contract, producing movement in or maintaining the position of parts of the body. In the figurative sense, the term muscle is used to refer to a person’s strength. More on that, later.

Delving a bit deeper into the physical definition, muscles produce both force and motion, and are responsible for maintaining and changing posture, locomotion, and movement of internal organs (such as the heart). There are three types of muscles in the body: skeletal (voluntary) , cardiac (heart), and smooth (involuntary)  muscle. For our purposes, we will focus on the building of skeletal muscles in the body. Skeletal muscles are anchored to bone by tendons, and are used to affect skeletal movement. Skeletal muscles are generally clumped into groups based on location (for example – core muscles include pelvic floor muscles,transversus abdominis, multifidus, internal and external obliques, rectus abdominis, erector spinae, and the diaphragm), with some muscle groups being larger (in surface area) than others. The more a muscle is used in daily living (for example, we use our legs more than we use our arms), the ber (and generally larger) a muscle will be.

Skeletal muscles are composed of connective tissue, collagen, elastic fibers, and other good stuff. At the heart of muscle motion is the myofibril (a strand of muscular protein),  which is composed of thick and thin filaments. Muscle contraction occurs when synaptic input from motor neurons results in thin actin and thick myosin filaments sliding past one another. While the mechanisms of muscular motion are complex and difficult to explain, the building of muscular tissue is not.

What Causes Muscles to Grow

There are three main mechanisms to achieving muscular growth, and they are: muscular tension, muscular damage, and metabolic stress. Muscular tension involves progressive overload – the gradual increase of stress placed on the muscles in training by increasing the weight load. This then leads to muscular damage – the breaking down of the aforementioned muscular tissue (myofibrils), and metabolic stress via swelling around the muscle. Those three factors combined lead to the muscle – with adequate nutrition and rest – repairing itself.  The broken myofibrils will fuse back together, while new myofibrils will also be generated. Your muscles, in essence, adapt to stress by becoming bigger (more myofibril strands) and ber (better synaptic connections with repeated use)..

Why do we Need to Build Muscle

Besides being aesthetically pleasing, building muscle in the body has numerous physiological and health-related benefits. Besides earning bragging rights for how much you lift, more muscle means you’ll burn more calories at rest, you’ll be ber, you will reduce your risk of injury and you will increase your stamina for other activities. Muscle also takes up less space than fat, which means the more muscle you have the trimmer and more toned you’ll look, at any given weight.

How do we Build Muscle

We have actually touched upon this before in another article, but there are three definitive styles of weight training to build quality muscle. They are training for hypertrophy – size, and training for power.

  1. Training for hypertrophy (size) – this involves higher rep volume, shorter rest periods, and lower weight loads than those used for power-training. This is the most commonly used training style for bodybuilders.
  2. Training for power – this involves lower rep volume, long periods of rest, and maximum progressive overload. Olympic lifters and powerlifters both utilize these methods of training for power.

Muscle Building Tips and Tracking Progress

The following are just some helpful hints and tips/tricks to getting started on building muscle:

While the biology and mechanics of muscular growth are rather complex, the actions required to grow lean muscle mass are not. Get off the treadmill and into the weight room, and reap the benefits forever.