7 Layers of Muscle

 JL F.I.T. Trainers specially design personal workout programs, exercises, and nutrition plans that target all seven layers of muscle tissue.
Jenny Farber, founder and owner of JL F.I.T., is able to understand and apply the seven layers of muscle tissue after working in the Physical Therapy world. Utilizing her knowledge of the seven layers, JL F.I.T. Trainers are able to maximize not only your workouts, but give you a clearer understanding of why stabilization, compensation of weak areas, and strength over your entire body is so important.

Humans have seven layers of fascia starting from the skin down to the bone. Cells group together in the body to form tissues: a collection of similar cells that group together to perform a specialized function. There are 4 primary tissue types in the human body: Epithelial Tissue, Connective Tissue, Muscle tissue, and Nerve Tissue.
  • Epithelial Tissue - The cells of epithelial tissue pack tightly together and form continuous sheets that serve as linings in different parts of the body. Epithelial tissue serves as thin layers of lining organs and helping to keep the body's organs separate and protected. Some examples of epithelial tissue are the outer layer of the skin, the inside of the mouth and stomach, and the tissue surrounding the body's organs.
  • Connective Tissue - There are many types of connective tissue in the body. Connective tissue adds support and structure to the body. Most types of connective tissue contain fibrous strands of the protein collagen that adds strength to connective tissue. Some examples of connective tissue include the inner layers of skin, tendons, ligaments, cartilage, bone, and fat tissue. In addition to these more recognizable forms of connective tissue, blood is also considered a form of connective tissue.
  • Muscle Tissue - Muscle tissue is a specialized tissue that can contract. Muscle tissue contains the specialized proteins actin and myosin that slide past one another and allow movement.
  • Nerve Tissue - Nerve tissue contains two types of cells: neurons and glial cells. Nerve tissue has the ability to generate and conduct electrical signals in the body. These electrical messages are managed by nerve tissue in the brain and transmitted down the spinal cord to the body.
Details of the different layers of muscle tissue and what their functions are:
  • Cardiac - Cardiac muscle tissue forms the bulk of the walls of the heart. Like skeletal muscle tissue, it is striated (the muscle fibers contain alternating light and dark bands (striations) that are perpendicular to the long axes of the fibers). Unlike skeletal muscle tissue, its contraction is usually not under conscious control (involuntary).
  • Smooth - Smooth muscle tissue is located in the walls of hollow internal structures such as blood vessels, the stomach, intestines, and urinary bladder. Smooth muscle fibers are usually involuntary (not under conscious control), and they are non-striated (smooth). Smooth muscle tissue, like skeletal and cardiac muscle tissue, can undergo hypertrophy. In addition, certain smooth muscle fibers, such as those in the uterus, retain their capacity for division and can grow by hyperplasia.
  • Skeletal - Skeletal muscle tissue is named for its location; it's attached to bones. It is also striated. Skeletal muscle tissue can be made to contract or relax by conscious control (voluntary).
All skeletal muscle fibers are not alike in structure or function. For example, skeletal muscle fibers vary in color depending on their content of myoglobin (myoglobin stores oxygen until needed by the mitochondria). Skeletal muscle fibres contract with different velocities depending on their ability to split Adenosine Triphosphate (ATP). Faster contracting fibers have greater ability to split ATP. In addition, skeletal muscle fibers vary with respect to the metabolic processes they use to generate ATP. They also differ in terms of the onset of fatigue. Based on various structural and functional characteristics, skeletal muscle fibers are classified into three types: Type I fibers, Type II B fibers and type II A fibers.