How Do Muscles Work?

Max Effort Muscle

If you have been keeping up on Max Effort Muscle’s product articles you have likely come across some terms and references to physiological processes that may be less than familiar. The aim of this article is to help elucidate some of technical mumbo jumbo and provide a broader context to not only help you understand the multitude of benefits seen from taking the Max Effort Muscle products but to help you learn more about the way your own body operates.

            Let us begin by discussing a topic that has come up in many of our product articles, muscular contraction. Many of the products and ingredients we have discussed play some role in helping increasing muscle growth by improving the efficiency of the muscular contraction. Previous articles have touched on the processes behind it but we want to help put the pieces of the puzzle together.

How do muscles contract? Well there is a well-supported theory known as the Sliding Filament Theory that explains the cellular process in a series of steps where myosin and actin grab onto each other, causing the sarcomere to shorten and how calcium ions are also important and yada yada yada. We could bore you with all those details but then only about a couple of you would make it to the end of the article. So instead lets be a little more practical. Muscle contraction starts in the brain with the release of the neurotransmitter Acetylcholine (Ach). Acetylcholine is the primary neurotransmitter in muscle contraction. When Ach is released it stimulates a nerve impulse, which travels down to the muscle and turn on the necessary muscle fibers. Once the nerve impulse reaches the muscle it activates the fibers and can be referred to as a motor unit. Simply put, a single motor unit is a nerve impulse and all the muscle fibers it innervates. These motor units are the basis for all movement and the more strenuous the task, the more motor units you need to recruit to accomplish it.

Now lets go a little deeper. There are a variety of muscle fibers, which can be activated by these nerve impulses. Likely you have heard of slow twitch (Type 1) and fast twitch (Type 2) muscle fibers but there are actually several others and several subtypes within these divisions but we will not go that deep. Slow twitch muscle fibers are oxidative, meaning they utilize oxygen for energy. These types of muscle fibers are being trained when you go for a jog or do light, low intensity activity especially over an extended period of time. Fast twitch fibers come in several varieties but we will discuss two, oxidative-glycolytic and glycolytic. Oxidative-glycolytic fast twitch fibers can utilize oxygen or glycogen (a form of glucose aka carbohydrate) for energy. Think of the oxidative-glycolytic fibers as being more of the intermediary, sort of a transition fiber between the slow twitch and the glycolytic fast twitch fibers. Fast twitch glycolytic is where the gains are so to speak. These are the large and powerful fibers that everyone looking to pack on muscle mass and strength seek to activate. These are trained only at peak intensities. The fast twitch glycolytic fibers are the last fibers to be turned on. Your muscles do not fire all muscle fibers where some fast twitch and some slow twitch kind of turn on in unison. Muscle fibers activate in an all or nothing fashion meaning an individual fiber cannot become partially active. A whole muscle group (i.e. biceps) can contract partially, without every single fiber firing, but at the micro level an individual fiber either activates completely or not at all.

Muscular contraction works as a progression. First comes the slow twitch then the oxidative-glycolytic fast twitch and then finally the fast twitch glycolytic. As a given workload becomes more difficult we require more fibers to lift. For example, you begin doing bicep curls with 25lb dumbbells, at the onset of the exercise you may not be straining at all to complete each rep, at this point you are only activating slow twitch fibers or very few fast twitch fibers. As the set progresses and you reach rep number 8 or 9 it gets much harder, now you need to recruit more and more fast twitch fibers in order to complete the exercise through the appropriate range of motion. This is why it is commonly said that the last two or three reps is where the magic happens. During these final reps you activate your fast twitch glycolytic fibers the most. If you quit early however, your fast twitch fibers are never activated, thus never trained and you will not see the progress you want. Quitting early on a set and expecting to see gains without ever activating your fast twitch glycolytic fibers is like doing calf raises and expecting to get massive biceps. You have to train what you want to improve so train the fast twitch glycolytic fibers, don’t quit early, and get stacked! Activating the glycolytic fibers requires Max Effort and our supplements (Max Effort Muscle Pre Workout and Test Booster) will enhance your exercise capacity so you don’t feel so lethargic in the gym, you will want to grind out those last few reps and see what you are made of! 

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Hall, S. J. (2006). Basic Biomechanics, 5th ed. New York, NY: McGraw Hill.

Patton, K. T. & Thibodeau, G. A. (2010). Anatomy & Physiology, 7th ed. St. Louis, MS:


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