The Chemistry of Building Muscle


Building Muscle is very important for sports, among other things. Having more muscles than an opponent will not only make you stronger than your opponent, but will give you more advantages such as increased endurance and speed as well. In a work environment, where manual labor is required, muscle will help you complete your job with more efficiency and ease than your non-muscular co-workers. I chose to research the chemistry of building muscle because I wanted to gain a better understanding of how muscles work, how they repair themselves when damaged, and how to build more muscle. Muscles affect my everyday life, because without them, I would not be able to do the things that are important to me, like playing soccer.Composition of ...

Motor End Plate: The complex end formation where a long, slender projection of a nerve cell (axon) from a motor neuron establishes synaptic contact with a skeletal muscle fiber.

Myofibrils: Basic, rod-like units of muscle cells.

Myofilaments: Chains mostly composed of Actin and Myosin, which are packed into a muscle fiber.

Myoneural Junction: The synaptic connection of the axon of a motor neuron with a muscle fiber.

Sarcolemma: The membranous sheath of a muscle fiber.

Sarcomere: Any of the segments of myofibrils in striated muscle fibers.

Sarcoplasm: The cytoplasm of a striated muscle fiber.

Sarcoplasmic Reticulum: A system of membrane-bound tubules that surrounds muscle fibrils, releasing calcium ions during contraction and absorbing them during relaxation.

Transverse Tubules: A deep invagination of the sarcolemma, which is the plasma membrane of skeletal muscle and cardiac muscle cells.

Z-Disc Ultrastructure: Plate-like structures in sarcomeres to which the plus ends of actin filaments are localized; the centre of the I-band.

Muscles are composed of many different parts. While some parts of a muscle have a more seemingly important job than others, all parts of a muscle are equally important. For example, sarcomeres are the basic unit of muscle tissue, which means sarcomeres are pretty important for muscles. Skeletal muscle is composed of tubular muscle cells, also referred to as myofibrils, which are composed of repeating sections of sarcomeres. Sarcomeres may seem to be more important than myofibrils, but without one, there would not be the other.

Main Chemicals, Compounds, Components

Myosin: Myosin is a protein found within thick filaments of muscle. Myosin can convert the chemical energy of ATP into mechanical energy, which creates the force and movement of muscle(s). Myosin is partly responsible for moving muscles, it works alongside alongside Actin, a similar protein found in the thin filaments of muscle. Myosin acts when a nerve impulse triggers a biochemical reaction within the muscle and makes it stick to Actin.

Actin: Actin is a protein found within thin filaments of muscle. It is also the most abundantly found protein in eukaryotic cells, and participates in more protein-protein interactions than any known protein. Actin is also partly responsible for moving muscles, and interacts with Myosin to create muscle contractions.

Chemistry's Role

When a nerve impulse triggers a biochemical reaction within a muscle, Myosin molecules in thick muscle filaments stick to Actin molecules in thin muscle filaments and lock, pulling thick and thin muscle filaments together. When thousands of Myosin and Actin molecules lock and pull muscle filaments together, muscle is moved. Myosin does not release Actin until another molecule, a catalyst, comes along and grabs the Myosin molecules, forcing them to release Actin molecules. This catalyst is called Adenosine Triphosphate (ATP). Bodies make ATP using oxygen. Not only is oxygen important for nourishing cells in the body, oxygen is also responsible for muscle movement. In order for muscles to be built, the body needs protein. Protein is made of amino acids, so without protein and amino acids, the body could not build, repair, or even maintain muscle tissue. Protein also contains oxygen, nitrogen, carbon and hydrogen. Having enough protein will put the body into an anabolic state, which allows the body to build muscle, and give it the oxygen it needs to move. When protein is eaten, hydrochloric acid from the stomach breaks it down into simpler forms, which the body has an easier time digesting. When muscles are strained, they rip a little bit. The broken down protein is then sent to the ripped muscle(s) and fills in the rips. The filling in of the rips causes the muscles to get bigger.

Background Research

When someone gains muscle, they do not also gain muscle cells. A human is born with all of the muscle cells they will ever have. When a person gains muscle mass, they just add mass to their pre-existing muscle cells.

In order to actually build muscle, you must first do something to the muscle that strains it. For most people, this “something” is weight -lifting. When a muscle is strained continuously, ie, multiple sets of repetitions, the muscle starts burning. This burning is caused by metabolic stress on the muscle. Metabolic stress causes sarcoplasmic hypertrophy, which just means the muscle and muscle cells swell. Sarcoplasmic hypertrophy is a way to increase muscle mass without necessarily increasing strength.

Also, when muscles are strained, they rip microscopically. Controlled ripping in muscles is good for building muscles; however, too little or too much ripping may be detrimental for building muscle. If too little or too much muscle rip occurs, muscles will not grow. When a muscle is ripped, it burns stored energy, which releases lactic acid. This release of lactic acid triggers something called an anabolic cascade. When this is triggered, the body repairs the damaged muscle(s) during the period of R.E.M sleep.

Resources (1)

    • skeletal muscles are made of myofibrils and sarcomeres.
    • myofibrils and sarcomeres form a muscle fiber.
    • skeletal muscles contract when receiving signals from motor neurons
    • motor neurons are triggered from sarcoplasmic reticulum
    • the better muscles are at receiving signals from motor neurons, the stronger they can get
    • after working out, body repairs damages muscles by fusing muscle fibers together
    • satellite cells act like stem cells for muscles
    • hormones affect muscle growth (2)

    • muscles tear when strained
    • muscles will not grow if there is too much/little tearing
    • lactic acid comes out when muscles burn stored energy
    • lactic acid triggers “anabolic cascade”
    • doing less gets more
    • nutrition nutrition nutrition (3)

    • burning when pumping caused by metabolic stress
    • metabolic stress causes the muscle and muscle cells to swell
      • makes muscles grow
      • increases muscle glycogen
    • swelling muscles called sarcoplasmic hypertrophy
    • can build muscle without increasing strength (4)

    • hormones help muscles grow, and help repair “broken” muscles
    • main hormones are testosterone and IGF (Insulin Growth Factor)
    • testosterone helps in many ways: it increases protein synthesis, inhibits protein breakdown, activates satellite cells, stimulates other anabolic hormones
    • 98% of testosterone is bound in the body and unusable
    • strength training releases testosterone and makes muscle cells more sensitive to any free testosterone
    • testosterone can stimulate growth hormone responses
      • increases presence of neurotransmitters at damaged fiber sites
        • can activate growth tissue
    • IGF regulates amount of muscle mass growth
      • enhances protein synthesis, facilitating glucose uptake, divides the uptake of amino acids into skeletal muscles
      • activates satellite cells to increase muscle growth

    • muscles made of proteins
    • proteins made of amino acids
    • muscle fibers are full of contractile fibers (myofibrils)
    • myofibrils divided into sarcomeres
    • sarcomere is made of actin and myosin

    • lots of strength doesn’t equal lots of muscle
    • size of muscle fiber is more important than number of muscle fibers
    • mitochondria make ATP
    • muscle fibers adapt to strain by increasing number of mitochondria in cells\
    • increase enzymes involved in oxidative phosphorylation and anaerobic glycolysis
    • also increases sarcoplasmic fluid inside cell, and glycogen
      • makes strength endurance
    • increases muscle’s ability to make ATP
    • ATP=energy for muscle contractions
    • trained muscles increase amount of actin/myosin filaments aka, sarcomeres

    • lactic acid=molecule that provides energy
    • 2-hydroxy-propanoic-acid
    • energy stored in glycogen, mostly in muscle cells and liver
    • glycogen breaks down into glucose and pyruvic acid
    • pyruvic acid deprotonates to make pyruvate ion
    • ATP then released

    • actin filaments are made of two strands of actin wound around each other
      • thin filaments
    • myosin filaments contain myosin. have bulbous ends called myosin heads
    • myosin filaments arange with heads in opposite directions
      • thick filament
    • myosin and actin filaments make sarcomeres
    • Z-lines make boundaries of sarcomeres
    • each myofibril contains thousands of sarcomeres

    • Information on the composition of Muscle
    • Refer to “The Composition of Muscle”
    • Components of Muscle

    • The two main components of muscle
    • Refer to “The Composition of Muscle”
    • Main Chemicals, Components and Compounds of Muscles

    • Information about Actin

    • Info about the roles of Actin and Myosin in a muscle

    • Info about myofibrils and sarcomeres

    • Info about anabolic growth

    • Motor end plate information

    • Definitions of the components of muscle

    • Info on protein and how it helps muscles repair and function

  • Info on protein and how it helps muscles repair and function

About the Author

Jens Zimmermann is a junior at Senior High. His hobbies include playing soccer, traveling, and making people feel good. Jens has lettered in Soccer and Orchestra, and has traveled to Europe, South America, and Africa. Jens believes that traveling is the most valuable and important thing that has happened to him in his life so far. His most memorable travels include summiting Mt. Kilimanjaro in Tanzania, Africa; visiting Rio De Janeiro, Brazil during the 2014 World Cup; and roaming the streets of Chefchaouen, Morocco. Jens plans to pursue a future career in whatever brings him joy, but will allow himself time to continue travelling.