Types of muscle: SKELETAL MUSCLES make up 1 of 11 entire body systems, composed of 600+ muscles, which together account for ½ our body weight. CARDIAC MUSCLE refers directly to the heart. SMOOTH MUSCLE consists of the gut, arteries, veins and muscles of the eyes. Cardiac and Smooth muscles are influenced by the Autonomic Nervous System, which simply means we do not consciously utilize them.

This Muscle Diary is concerned primarily with Skeletal Muscle, which is governed by the Somatic Nervous System, of which is consciously and reflexively controlled. We will address aspects of mechanical and physiological function as it pertains to everyday living/exercise as well as importance/relevance to remedial care, i.e.: Manual Medicine Practitioners/Trainers/Coaches/You – knowing yourself and what you’re made of and how you work.

Some of the more common and relevant skeletal muscles discussed readily in Manual Therapy:

What is Skeletal Muscle?

• Actin and Myosin, contractile proteins, form sarcomeres. 
• Sarcomeres are the smallest functional unit of a Skeletal Muscle. Many sarcomeres form a myofibril. 
• Many myofibrils form a muscle cell/fibre.
• Many muscle fibres form fascicles. Fascicles are arranged in neat: circular, convergent, parallel, and pennate forms. 
• Many fascicles make a muscle belly. Some Skeletal Muscles have multiple bellies, like the bicep which has 2, tricep-3, quadricep-4. Each muscle belly is manually/palpably distinguishable.

How does Skeletal Muscle Function?

Skeletal Muscle Contraction: Once an action potential travels down a nerve to the end-bulb at the synaptic cleft, where the nerve meets the muscle, calcium ion channels open allowing calcium to flow into the end-bulb of the nerve, creating a more positive environment on the inside of the nerve fiber forcing its’ vesicles to release acetylcholine (neurotransmitter) into the synaptic cleft. Acetylcholine binds to the ligand-gated ion channels of the muscle where sodium is then able to rush in to the muscle fiber causing a muscle contraction! (Recall the actin and myosin mentioned above – the contraction happens here, in the sarcomere – the functional units of a muscle fibre). After this happens, acetylcholine detaches from the ligand-gate, where an enzyme comes to recycle it and sodium rushes out of the muscle fiber and remains in the synaptic cleft until another action potential calls upon it. Therefore, there are little pools of metabolic constituents (acetylcholine, sodium, calcium, etc) always hanging around waiting to do work.

Why is this Important?

Action potentials are voltage-gated, where as ligand-gates are chemically initiated. There are also mechanical-gates which Massage/Manual Therapy/exercise exploit in order to achieve specific goals. This understanding leaves us with 3 areas for issues to arise, altering function and perhaps requiring you to seek therapy. 1. Mechanics is structural injury to the muscle itself (mechanical-gates). 2. Nerve conduction may be structural or metabolic affecting voltage gates. 3. Metabolic issues of consumption/blood origin (ligand-gates). Manual Therapy can provide as passive aid, influencing any and perhaps all of these gates in the function of movement..

Furthermore, uniformity in contraction is important, spreading load evenly throughout a field of biomechanical play. If this is not possible the body will adapt to provide the next best way. Sometimes our muscle fibres will grasp one another tightly in attempt to retain function. When this happens we feel it as a knot or hypertonic point. If when pressed that knot refers discomfort or pain to an area other than its own, this is a Trigger Point. Manual Medicine, like exercise, helps prevent knots, maintain load dispersal increasing the adaptive potential of body tissues. Through therapy/exercise there is micro tearing of the tissue. As a result angiogenesis ensues – building of new blood vessels in a process of meta-routing blood to heal the area. This is an adaptive process. This process may cause discomfort, as we often feel after physical exertion and sometimes after a Manual Therapy session. Hence the phrase, “No Pain, No Gain”. Conversation with your therapist, experience with proper exercise, will aid you in distinguishing between therapeutic pain/discomfort opposed to unwanted pain/discomfort.

Awareness in biomechanics (form) allows us to micro tear (destroy) and promote (help build) appropriate lines of tension, both actively through activity and passively through therapy. This makes form during exercise and awareness/knowledge from your therapist necessary. In addition, this also makes stretching, strengthening, and cardiovascular maintenance equally important. Stretching ensures mutual communication between muscle fibres preventing knots, strengthening feeds the muscle fibre amplifying its capacity for power generation, and cardiovascular exercise ensures adequate food is available for muscle fibre function as well as maintains a healthy heart rate for all moments lived.

Stay tuned for more Muscle Diary - Bianca Anzovino – RMT, Acupuncture & Dry Cupping Provider @ Lemon Water Wellness. bnarmt@gmail.com 
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FUN FACT: There are tiny muscles that allow our hairs to stand up in the effect of giving us “goosebumps” – Erector Pili are their names.
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At 9 Mill St. we want you to understand, in the best way we know how, what you are made of and how to take the best care of you and your friends and family. We learn from your questions, so drop by/book in!