Lecture III Muscle Imbalances

Tools for Managing Back Pain

Lecture III

Spinal Stability Muscles of the Torso & Hips

Posterior Spine Musculature

Superficial Abdominal Wall Musculature

Abdominal Musculature

Posterior Abdominal Wall

Traditional Method of

Muscle Anatomy of the Torso

Traditional anatomy descriptions of the spinal muscles have only taken a look at the posterior view or from the back.

Muscles are typically studied or viewed as straight line cables.

A Different Perspective

A more current understanding of muscle anatomy involves how movement is created and joints are stabilized.

Rotatores & Intertransversarii A Different Role in Movement

Many anatomy books describe the function of the rotatores as small rotator muscles of the spine. The intertransversarii as lateral flexors of the spine.

According to McGill (2002), these muscles are very tiny and do not create movement.• However, they may function as vertebral

position sensors at every thoracic and lumbar joint.

Rotatores and Intertransversarii

Extensors of the Spine

Extensors of the Vertebral Column MultifidiSemispinalis Longissimus Iliocostalis Spinalis

Quadratus Lumborum

Extensors of the Back

Another View of the Back Extensors

Extensors:Longissimus, Iliocastalis, and Multifidi Groups

The major extensors of the thoracic and lumbar spine.

The role of these muscles is different in the two areas of the spine.• Thoracic:

These muscles attach to the ribs and the thoracic vertebrae with long tendons that run parallel to the spine and attach at the sacrum and iliac crests.

The thoracic extensors run just under the fascia over the lumbar spine.

These extensors have the greatest moment or torque.

Weak Thoracic Extensors

According to a study from the American Journal of Neuroradiology 2005, the development of extreme thoracic kyphosis might contribute to excess biomechanical stress in the spine and may identify a population at risk for future vertebral compression fracture at the thoracolumbar junction.

Extensors of the Lumbar SpineIliocostalis lumborum pars lumborumLongissimus thoracis pars lumborum

These muscles originate over the posterior sacrum and go at an angle and deeply attach to the lumbar vertebrae.

Injury or load to the lumbar spine increase when there is flexion of the spine. These muscles lose their angled attachment with spinal flexion increasing the load or force to the spine.

The extensors of the lumbar spine create a shearing force in flexion.

This is, unfortunately, the way most people bend over to pick something up. Therefore, increasing risk of injury to the spine and muscle tissue.

Spinal Flexion = Load

Decreased Load to the Lumbar Spine

Loads to the Back

During lifting, muscles and ligaments significantly increase loads to the spine.

In weak spines, a spinal load of 7,000N or 1,560lbs begin to damage the spine. Think of how many times you bend over during the day to pick something up!

In young healthy spines, 12-15n or approximately 2,600-3,360 lbs begin to load the spine.

In weight lifters with ideal mechanics, the load can increase to 4,480lbs.

Lifting Skills and Strong Backs A good skill to have!

One avoids injury to the back when you flex at the hips, therefore reducing or minimizing tissue tension.

If you are flexed at the hips and not the spine, there is a increase in thoracic extensors and the lumbar extensors do not increase the load to the spine.

The abdominal muscles are activated by creating a “corseting” effect stabilizing the spine through abdominal bracing.

A Safe Lifting Technique

Loads to Back in Extension

According to Callaghan, Gunning and McGill (1998), to have safe therapeutic muscle activation for the lumbar extensors, one must activate one side of the spine at a time.

As discussed previously, there are four sections of the extensors. Right and left thoracic and right and left lumbar.

Therapeutic Exercise?

Increases the load to the spine to 6,000N or over 1,300 lbs.

It certainly does activate all 4 sections but with injury to the spine.

Therapeutic Exercise

Increased Load to Spine with Flexion and Extension of the Spine

Better to Squat if you can!

The perfect squat!

The Mutifidus Muscle

Multifidus

These muscles only span a few joints or vertebrae and the force they apply is very localized.

The multifidus does play a role in stabilizing but cannot be isolated.

Latissimus Dorsi

The “lats” are involved in lumbar extension and spinal stabilization.

The latissimus is active during pulling and lifting.

Activated in Bird Dog with arm and opposite leg activated, rows and pull downs.

Latissimus Dorsi

Abdominal Muscles

Rectus Abdominus

Trunk flexor. Why is it segmented instead of one

long muscle?

• Possibly to facilitate flexion/extension of the torso and to assist with abdominal distension or contraction as volume changes ( M. Belanger, 1996).

Three Layers of the Abdominal WallInternal and External ObliqueTransverse abdominus Functional point of

view• Work together and

independently.• The oblique's

create a twisting and lateral bend and enhance flexion.

• Rectus primarily creates flexion.

Upper and lower Abdominal Wall• According to

Leman and McGill, 2001, there is no separation of upper and lower ab wall.

The Most Important Pointof

Spinal Stability

The oblique's and the transverse abdominus form a hoop around the entire torso creating stability or stiffness for improved spinal stability.

The Psoas

The Psoas Continued

Attaches to T12 and to all the lumbar vertebrae and to the femur.

The psoas is a hip flexor and not a spine stabilizer Juker, McGill and Kopf, (1998). This is because it attaches to the lumbar vertebrae, creating a stiffening of the spine only when the hip is flexed (McGill 2005).

Stretching the Psoas

Quadratus Lumborum

Attaches to each of the lumbar vertebrae, pelvis and rib cage.

QL continued The quadratus lumborum, or QL, is a common source of

lower back pain.

The QL is capable of extending the lower back when contracting bilaterally, the two QLs of the low back pick up the slack, as it were, when the lower fibers of the erector spinae are weak or inhibited (as they often are in the case of habitual seated computer use and/or the use of a lower back support in a chair).

There is a mechanical disadvantage created by constant contraction while seated which can overuse the QLs, resulting in muscle fatigue.

A constantly contracted QL, like any other muscle will experience decreased blood flow, and will create muscle spasms over time.

Back Break

& Stretch

Core is Good Spinal Stability

True spine stability is accomplished by a balanced “stiffening” from the entire musculature of the torso.

This includes the abdominal wall, quadratus lumborum, latissimus dorsi and the back extensors of longissimus, iliocostalis and the multifidus.

There is not a single muscle that is responsible for spinal stability like the transversus or multifidus. Very few individuals can singularly activate these muscles. By attempting to recruit these muscles by drawing in ones ab wall, one creates instability when they are attempting to increase spinal stability by “hollowing” (McGill 2009).

Core The core muscles differ from the arm and leg muscles in

that the muscles co-contract stiffening or corseting the trunk so that all the muscles work together synergistically. Therefore, training the muscles of the core is different than training the muscles of the limbs.

  The core generally functions to prevent motion rather

than initiate it. Activities of daily living need power to come from the hips and transmit to a stable torso. Pushing, pulling, lifting, carrying and efforts of the torso are compromised by the spine bending or what are called “energy leaks”. These energy leaks over time can accumulate and create an injury to the spine.

Energy Leaks

What are Energy Leaks? Energy leaks are caused when weaker

joints are forced into eccentric contraction by stronger joints.

Energy leaks are points at which energy is lost during the transfer of force from the ground. Energy leaks are a result of the inability of the body to stabilize a particular joint.

Examples of Energy Leaks

Sitting with a rounded back.

Squats with rounded back or knees that cave in.

Lifting a child, lifting groceries with a rounded back poor posture.

Walking or running with with hips that have a great deal of movement.

Energy Leaks create injury.

Contraindications to a More Stable Spine

Standing on an unstable surface. Sit ups. Stretches that emphasize knee to chest

or toe touches. Using a physioball does not create

spinal stability. To use seated with rounded posture is a significant “energy leak”.

Spinal Loading Exercises

Yes, and more….the list is endless!

One more….this could be a very effective exercise if standing with good spinal stability and “braced”.

STA

BILIT

Y

EX

ER

CIS

ES The “Bug”

SPIN

AL S

TAB

ILIZATIO

N

EX

ER

CIS

ES

Basic Quadruped

SPIN

AL S

TAB

ILIZATIO

N

EX

ER

CIS

ES

Bird Dog : Do not add leg extension and arms until basic Quadruped is mastered

SPIN

AL S

TAB

ILIZATIO

N Bird Dog with Sweep

AD

VA

NC

ED

AB

DO

MIN

AL

BR

AC

ING

Off set load with hand to the side

SPIN

AL S

TAB

ILIZATIO

N Basic Side Bridge

AD

VA

NC

ED

SID

E B

RID

GE Feet can be either stacked or in front for

different muscle recruitment

SP

INA

L S

TA

BIL

ITY

EX

ER

CIS

E Stir the Ball

The Kinetic Link“the hip bone is connected to the knee bone”

Kinetic Link Injury

Examples of what can lead to an injury further up or down the kinetic link.Old ShoesOver Pronation, Under Pronation, High

Arches Back Pain

Gluteal amnesiaShortened hamstringsShortened hip flexors

PsoasQuadriceps: Rectus Femoris

More on the Kinetic Link

Lateral hip pain, knee and foot injuriesGluteus mediusTrochanteric bursitisIT Band SyndromeMeniscal InjuriesACL injuriesPlantar fasciitis

Thank you

References

Bartynski, W.S, Heller,M.T., Grahovac,S.Z., Rothus, W.E., and Kurs-Lasky, M. (2005) Severe Thoracic Kyphosis in the Older Patient in the absence of Vertebral Fracture : Association of Extreme Curve with Age. American Journal of Neuroradiology, 26:2007-2085.

Nitz, A.J., and Peck, D. (1986) Comparison of muscle spindle concentrations in large and small human epaxial muscles acting in parallel combinations. American Surgeon, 52:273-277.

Bogduk, N (1983) The innervation of the lumbar spine. Spine, 8:286.McGill, S.M., and Norman, R.W. (1987) Effects of an anatomically detailed erector spinae

model on L4/L5 disc compression shear. Journal of Biomechanics, 20 (6):591.McGill, S.M., Hughson, R.I., and Parks, K. (2000) Changes in lumbar lordosis modify the

role of the extensor muscles. Clinical Biomechanics, 15 (1):777-780.