The Five Main Muscles for a Full Range of Natural Movement, Dynamic Alignment & Balance.

Epistemic status. Full confidence. The anatomy is easily verifiable. Working towards fully utilising these muscles has changed my life. My story here.

For a less wordy introduction to the anatomy try here: The 5 Main Muscles Made Easy.


Following an introduction to our midline anatomy and the median plane as the references for alignment and balance of the human body, think about how you move.

Do you move well?

Our System For Movement.

The main components of our ‘system for movement’ are:

  • Muscles (The movers—tissue of action—background notes on muscles.)

  • Bones (Solid frame, attachment points for muscles.)

  • Brain (HQ. Receiving and processing sensory information and sending commands to body.)

  • Mind (Observer and controller.)

  • Nerves (Communication network.)

  • Connective tissues (Just about everything else). We are physically interconnected from head to fingers to toes by the body-wide web of connective tissues (various forms of fibrous tissue) .

Do you have a full range of natural movement?

A Full Range of Natural Movement.

A full range of natural movement is what your body should be able to do. Your full potential. Not what you are currently able to do.

When the body is balanced, movement can flow through all potential positions. The head, arms and legs can all be moved independently, through their full range of motion, in a smooth and controlled manner, without effort or strain.

Examples of some of the body’s capabilities.

To give some an idea of what the body is capable, consider the number of moving joints of the body (I’m not happy to provide a figure but various suggestions appear here on Quora.) and the range of motion of those joints (not an exhaustive list e.g. there’s no data for the spinal column). The slightest movement in any joint—flexion, extension, adduction, abduction, rotation depending on the joint’s capabilities—creates a novel pose. The body has innumerable positions—our posture/​positioning/​movement is a flow.

A full range of natural movement is possible when the body is functioning at optimal, dynamically balanced and aligned. ( what does alignment mean?)

Anatomy of alignment and balance (recap):

The linea alba and nuchal & supraspinous ligaments are our main anatomical guides for body alignment.

Midline anatomy of the linea alba and nuchal and supraspinous ligaments aligned on the median plane.

These midline structures are strips of tough connective tissue that we have no direct control over, we can however influence 2 of our components of movement—muscles and mind - and learn to work with the adjacent muscles (see below for some background notes on muscles) to:

  • Increase awareness of the sensory feedback from adjacent muscles to feel the relative positioning of our midline anatomy. Developing conscious awareness of our sense of proprioception.

  • Increase voluntary control of the relevant muscles. Focusing on activating the adjacent muscles allows us to work towards physically aligning the linea alba and nuchal & supraspinous ligaments and regaining a full range of natural movement.

Whatever exercise you do, routines, sports etc… be more aware of the positioning of your body (posture) and your state of alignment by working with your “5 main muscles of movement”.

According to Base-Line Theory of Health and Movement:

The 5 Main Muscles of Movement are:

1. Pelvic Floor.

(The pelvic floor consists of several muscles that can be thought of one unit.)

The “pelvic floor” are the muscles that span the pelvic canal. Also known as the pelvic diaphragm.

Left and right sides of the pelvic floor are a mirror image, the line of symmetry the body’s midline.

The pubic symphysis (where the linea alba and rectus abdominis muscles attach to the pelvis) is located on the midline of the anterior border of the pelvic canal.

To describe the pelvic floor in detail would be time-consuming—and frustrating. The anatomy is complicated with some controversy with regards to nomenclature, and is unimportant to this process. Think of the pelvic floor muscles as one unit of two halves.

My comments.

The pelvic floor muscles—a basket of muscles that should be tight and secure.

Activate your pelvic floor muscles and think of them at the root of all movement.

The solid Base for the the rest of the body.

2. Rectus Abdominis.

The left and right rectus abdominis muscles run parallel to each other, either side of the linea alba, up the front of the abdomen from pelvis to thorax.

The rectus abdominis muscles attach to:

  • Pubic symphysis and pubic crest of the pelvis.

  • Costal cartilages of the 5th, 6th and 7th ribs (on the medial inferior costal margins).

  • Posterior aspect of xiphoid process of the sternum.

The rectus abdominis muscles consists of several panels’ of muscle between strips of connective tissue known as tendinous intersections.  These sections of muscle are what gives the rectus abdominis the “6-pack” look, but the number of panels can vary between individuals − 4, 8, and 10 packs can occur.

The rectus abdominis muscles sit within their respective rectus sheath formed by the aponeuroses of the lateral abdominal muscles before they merge to form the linea alba.

My comments.

The rectus abdominis muscles—Our core pillar of strength. Our central Line. Strong and flexible, able to support the rest of the body through a full range of movement when fully utilised. Ribbons of muscle that can bend and rotate at every level.

Like two stacks of blocks to be activated in sequence from pelvis to chest.

Think longer and stronger with every in breath.

Fully engaging and elongating the rectus abdominis muscles extends the linea alba (our primary guide for alignment) to its full potential.

3. Gluteus Maximus.

Situated at the posterior of the pelvic region, the left and right gluteus maximus muscles are the largest skeletal muscles in the body. From pelvis to femur, the gluteus maximus provide stability to the hip joint when fully active.

The superficial muscle layer of the buttocks, covering and surrounded by a lot of complicated anatomy that is prone to various strains and syndromes when the gluteus maximus are not adequately functioning.

The gluteus maximus muscles attach to multiple structures, many more than the current standard description covers.

Attachments of the gluteus maximus:

  • The ilium of the pelvis (posterior to the posterior gluteal line {attaching to a narrow, semilunar area with a rough surface}, and the posterior superior iliac crest.

  • The sacrum (posterior inferior edge).

  • The coccyx (lateral sides of the posterior surface).

  • The aponeurotic fascia of the gluteus medius muscle.

  • The sacrotuberous ligament (posterior surface).

  • The tubero-iliac ligament (part of the long posterior {dorsal} sacroiliac ligament).

  • The thoracolumbar fascia. (Through its attachment to the raphe of the thoracolumbar fascia, the gluteus maximus is coupled to the ipsilateral multifidus muscle and to the contralateral latissimus dorsi muscle.)

  • The iliotibial tract. Three-quarters of the fibres form a superficial lamina (layer)which narrows and attaches between the two layers of the tensor fascia latae, forming part of the iliotibial tract. (a.k.a. iliotibial band.)

  • Gluteal tuberosity of the femur. Via an aponeurosis formed from the deeper muscle fibres. (The gluteus maximus attaches between the vastus lateralis and adductor magnus).

My comments.

The gluteus maximus muscles work in tandem with the rectus femoris muscles, stabilising the leg through a full range of movement.

The largest muscles of the body that position the leg to torso when fully engaged.

“Buns of steel”—Hands on buttocks. Feel these muscles contract and tighten.

The gluteus maximus muscles are superficial to, and surrounded by, a lot of anatomy prone to pain syndromes (caused by these main muscles not being adequately utilised?).

4. Rectus Femoris.

The rectus femoris muscles at situated at the front of each thigh, extending from pelvis to tibia.

The rectus femoris is traditionally described as part of the quadriceps femoris muscle group, along with the 3 vasti muscles (the vastus lateralis, vastus intermedius and vastus medialis).  

The distal tendons of the 4 quadriceps muscles merge to form the common quadriceps tendon, which attaches to the patella (kneecap) and then continues as the patellar ligament to the tibial tuberosity of the tibia. i.e. the quadricep muscles share a common insertion but rectus femoris attaches to the pelvis, whilst the 3 vasti muscles attach to the femur. The rectus femoris is the only muscle of the quadriceps that crosses both the hip and knee joints

The pelvic attachments of the rectus femoris muscles are commonly described as ”to the ilium of the pelvis via two heads—the straight head and the reflected head” but it is not that simple—variations in the pelvic attachments have been observed.

  • The tendon of the straight head attaches to the anterior inferior iliac spine.

  • The rectus femoris may also arise from the anterior superior iliac spine.

  • The tendon of the reflected head attaches in a groove above the superior rim of the acetabulum and the fibrous capsule of the hip joint. The reflected head may be absent.

  • A 3rd head may be present, attaching to the iliofemoral ligament deeply, and superficially to the gluteus minimus tendon as it attaches to femur.

The heads of the rectus femoris merge into an aponeurosis (a tough, thin sheet of connective tissue), from which the muscle fibres arise as the aponeurosis continues distally on the anterior surface of the muscle.

The lower two-thirds of the posterior surface of the rectus femoris consists of a thick, broad aponeurosis that becomes narrowed into a flattened tendon attached to the patella.  This forms the superficial, central part of the common quadriceps tendon.

My comments.

The rectus femoris muscles—a strong pole down the front of the thigh when engaged along their full length. Positioning the leg to the pelvis and aligning the hip and knee joints.

Feel each muscle contract between it aponeuroses—think of pulling your kneecaps up and pushing down from your hip bone.

5. Trapezius.

  • from mid-back (last thoracic vertebra—level with last rib)

  • to the base of the skull

  • extending out towards each shoulder

The left and right trapezius muscles are the most superficial muscle layer. Thin sheets of muscle that should be free to fully extend.

The trapezii (plural) meet midline, attaching to the nuchal ligament and supraspinous ligament.

The trapezii are sculpted down the neck and towards the shoulders, attaching to both scapula (shoulder blade) and clavicle (collar bone) of each arm—look at the shape.

Based on the direction of the muscle fibres, current descriptions split each trapezius muscle into 3 functional sections.

1. Upper trapezius. (a.k.a. superior trapezius, descending trapezius)

Attaches to:

  • Base of the skull. External occipital protuberance and medial third of the superior nuchal line of the occipital bone via a thin fibrous lamina.

  • Nuchal ligament.

  • Lateral third of the clavicle.

  • Spinal process of the 7th (last) cervical vertebra.

  • Supraspinous ligament.

2. Middle trapezius. (a.k.a. transverse trapezius)

Attaches to:

  • Spinal processes of the 1st to 4th thoracic vertebrae.

  • Supraspinous ligament.

  • Medial side of the acromion of the scapula.

3. Lower trapezius. (a.k.a. inferior trapezius, ascending trapezius)

Attaches to:

  • The spinal processes of the 5th to 12th (last) thoracic vertebrae.

  • Supraspinous ligament.

  • Posterior crest of spine of the scapula.

  • Deltoid tubercle of spine of the scapula.

Between the 6th cervical and 3rd thoracic vertebrae (the base of the nuchal ligament and start of the supraspinous ligament) the trapezius muscles are connected to the midline by a broad semi-elliptical aponeurosis, forming a tendinous ellipse between the shoulder blades.

Tendinous ellipse of connective tissue between the shoulder blades (scapulae), extending from the trapezius muscles.

My comments.

The trapezius muscles—from the back of the head to mid-back, extending out to each shoulder.

A kite-shaped blanket of muscle that should be smooth and wrinkle-free, supporting the head and arms through a full range of movement.

The trapezius muscles attach to the base of the skull via a thin sheet of connective tissue (lamina) and there is a ellipse of connective tissue at the base of the neck/​between the shoulder blades too.

Movement of the upper body should begin from the lower trapezii. Think extension and expansion from midline outwards.

The middle trapezii should spread wide allowing the arms to fully extend. Our upper limb includes the scapula.

The upper trapezii should be free of tensions, allowing the head to move through its full range of movement and alignment of the nuchal ligament.

the nuchal ligament, midline anatomy aligned by the trapezii.

Base-Line Theory of Health and Movement (part 1).

Learning to use these 5 (paired—left and right) main muscles movement is the key to better health. - Physical and mental.

Everything starts from your Base-Line muscles:

Pelvic floor—Base.

Rectus abdominis—Line.

The body’s Base-Line muscles are:

  • From where the rest of the body extends. The rest of the body is positioned relative to Base-Line.

  • Our muscular link to our ’primary guide for body alignment—the linea alba.

  • Our core pillar of strength.

  • Key to increasing our conscious proprioception i.e. increased awareness of our sense of position, movement and balance.

  • The main muscles to connect body and mind.

The Base-Line muscles should:

  • Fully extend, aligning the linea alba.

  • Flex and rotate at every level.

  • Support the rest of the body through a full range of natural movement.

Think solid Base and strong, flexible Line. (see below for how to start ‘breathing with your Base-Line’).

- - -

Our Base-Line muscles are two of the ‘5 main muscles of movement’ which, when fully utilised, provide the central framework for optimal functioning of the body.

Connect Your Base-Line to Your Legs.

Gluteus maximus & rectus femoris.

It should be possible to move each leg through a full range of movement in a smooth and controlled manner, without effort or strain, possible when the gluteus maximus and rectus femoris muscles of each leg work in tandem.

Engagement of these leg muscles is about feeling them contract and strengthen.   The rectus femoris a solid pole from shin to hip bone, aligning the hip and knee joints. The gluteus maximus the stabilising the legs to Base-Line support.

Aim for a full engagement of both muscles, left and right sides, balanced in all positions.

Connect Your Base-Line to Your Upper Body.


  • Do you have any connection to your trapezius muscles?

  • Can you activate them from mid-back up? Pushing your shoulders up from under, not pulling them up from above?

  • Can you feel your arms extend out from midline? Your shoulders free to move and rotate?

  • Can you let your head relax forwards? Fully, without tension?

The whole of both trapezius muscles should be free to fully extend in all directions, without pain or tension, supporting the head and arms through a full range of movement.

The trapezius muscles align the nuchal & supraspinous ligaments when they are fully utilised. Our secondary references for body alignment.

A Simple Technique—Breathing with your Base-Line.

  • Breathe in and up through your nostrils.

  • Breathe out through your mouth.

  • Engage your Base-Line muscles as you inhale.

  • Begin with your Base pelvic floor.

Take as many breaths as you need to feel your pelvic floor muscles engaging. The base of the physical body and starting point of the body map in the mind.

  • Then activate your central Line—rectus abdominis muscles.

Think of engaging and elongating your rectus abdominis muscles section by section, in sequence from pelvis to chest.

Stronger and longer with every in breath, extending the linea alba, our primary guide for body alignment.

Don’t rush, just breathe. Wherever you are!

Be aware of when ‘the wrong’ areas of muscle activate.  When you feel this happening—relax, breathe and focus on your Base-Line muscles once more.

I used the roll-down action a lot—my go-to move. Feeling my Base-Line supporting the rest of my body.

Don’t worry about where your feet are to start, everything stems from your Base-Line.


Maintaining the body is not about doing specific exercises or reaching certain poses.

Work towards a full range of movement by focusing on these five main muscles, starting with your Base-Line.

Pelvic floor Base, rectus abdominis Line.

When these main muscles of movement are free to be fully utilised the rest ‘falls into place’ . The body is strong and movement flows when we can achieve dynamic alignment and balance. At least that’s what I’ve found. I just need a few others to find out for themselves how lesswrong I am!

Part 3: Conscious Proprioception—Your Sense of Position, Movement & Balance.

Background Notes on Muscles:

Muscle Engagement & Activation.

An ‘active’ muscle is traditionally is described as “contracting”, but this implies a reduction in length or decrease in size which is often not the case.

The 3 standard classifications of how a muscle ‘contracts’ are:

  • Concentric contraction—shortening of muscle tissue.

  • Eccentric contraction—lengthening of muscle tissue.

  • Isometric contraction—muscle length remains the same.

I prefer to use ‘activating’ and ‘engaging’ when it comes to discussing the usage of muscles. I like ‘engaging’ but I’ve had poor feedback. I continue my search for the perfect word—suggestions?!

Muscle Cells = Muscle Fibres.

Muscles consists of ‘hundreds of thousands’ (no figures available!) of elongated muscle cells (myocytes) surrounded by connective tissue. These cells are commonly known as muscle fibres.

several muscle fibres (muscle cells)
cross section of muscle fibres, surrounded by connective tissue (collagen fibres)

Areas of Muscle.

It is not “all or nothing” when a muscle works.

Muscles consist of many overlapping areas of potential activity. Some muscle fibres may be active whilst others are resting, or spasming in an individual muscle.

Voluntary Muscles.

Voluntary muscles are muscles with “an action that is under the control of the will”.

All striated muscles (except the heart) are voluntary i.e. we can consciously control all our muscles if the connection between brain (command center) and muscle is developed.

Test Yourself …

Are you willing to do a bit of self-experimentation and consider how your body moves?

Find the 5 main muscles of movement—palpate them on your body.

Can you connect with them? Feel them? Activate them?

It may take a while for ‘activation signals’ to to get to the right place, and the ability to fully engage the whole of a muscle comes with practice.

Time and effort.

To balance the body. And mind.

There are many idiopathic (of unknown cause) symptoms and syndromes associated with chronic pain.   No known cause means no effective treatment.  No relief for those who suffer.  I believe that only when the main muscles of movement are being used correctly can their dysfunction be ruled out as the cause of the otherwise mysterious, painful symptoms experienced by so many.