NCSF Personal Training Study Guide Chapter 3 – Kinetic Chain Function, Dysfunction, and Corrective Exercise

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Chapter Goals:

• Know the concepts of form and force closure.
• Discuss the kinetic chain.
• Know the differences between phasic and postural muscles serving to facilitate stability.
• Know the concepts of function.
• Understand muscular units and postural distortions.
• Know the basics of corrective exercise.

Local and Global Systems

Muscles and joints constantly interact to help move and stabilize the body in physical activity.

Major Factors Influencing the Transfer of Force

The neural proficiency of muscle activation is the first factor in the ability to transfer force.

The second factor is the health and efficiency of the associated bones, joints, and ligaments.

The third major factor influencing force transfer would be added support of associated muscles and fascia.

Some major definitions to know for this start of the chapter:

Form closure – the efficiency of the structural aspects of articulating segments. Mainly this is made of the connective and skeletal tissues.

Force closure – the support from soft tissues that help to keep the integrity of the joint’s position.

Kinetic chain – this is the chain of force transfer across the moving segments of the body.

Local muscle systems – the muscles needed for joint stability and neutral positioning.

Global muscle systems – the muscles, typically larger ones, that are needed for motion and stability that functions in a phasic way.

Isometric contraction – this type of muscle contraction has no change at all in the angle of the joint.

Local Stabilizer Summary:

ROLE – used to increase the stiffness of the muscles and control movements of segments.

FUNCTIONS – for the control of neutral joint positions. The contraction of the muscles does not change length or movement.

CHARACTERISTICS – these fulfill proprioception functions, and activity is independent of the movement’s direction.

EXAMPLE MUSCLES – transverse abdominus, pelvic floor, diaphragm, deep lumbar, multifidus, soleus, vastus medialis, and posterior fibers of the internal obliques.

Global Stabilizer Summary:

ROLE – these are used for generating force and controlling the ranges of motion.

FUNCTIONS – these are used to control the inner and outer ranges of movements and tend to be the eccentric contractors for decorating loads of momentum or rotational control.

CHARACTERISTICS – the activities with these muscles are dependent on direction, and their activation is not continuous.

EXAMPLE MUSCLES – quadratus lumborum, psoas major, external and internal obliques, rhomboids, trapezius, levator scapulae, rectus abdominus, and hip adductors.

Global Mobilizers Summary:

ROLE – used for the generation of torque and production of movement.

FUNCTIONS – used to move joints, especially when the sagittal plane is involved. They tend to contract concentrically and absorb shock from most impacts.

CHARACTERISTICS – their activities depend on direction, and activation is not continuous.

EXAMPLE MUSCLES – external oblique, rectus abdominus, erector spinae, gastrocnemius, hamstrings, glute max, hip adductors, and latissimus dorsi.

The Integrated Model of Function

The isolation of muscle groups and particular muscles will be useful for the movement of joints, remedies for imbalances in strength, and recovery from injury. Still, the body never functions in these isolated ways.

Instead, the body prefers to integrate mechanisms for managing static positioning and movement.

The main role of the exercise professional is to reduce the risk of injury; thus, promoting musculoskeletal function is an important foundation to instill in programming.

There are three common physical components to look at in terms of human function:

• How well a joint is aligned is known as form closure.
• The ability of the connective tissues to keep joint integrity is known as force closure.
• The neuromuscular system’s proficiency level to anticipate and react to things through motor control.
• Emotion could be a fourth component. This is related to the psychological conditions that play roles in efficient movement.

If someone is suggested to be functional, this could mean these things:

• The musculoskeletal system keeps proper symmetry for the right form and force closure.
• Activation is both orderly and efficient with proper anticipatory signals.
• The local stability balance is achieved through the right antagonist and agonist muscle relationships acting on each joint.
• The overall force development happens without the constriction of the effective force couples, which results in energy conservation in static and dynamic activities.

Muscular Units

The Inner Unit

This is the collective group of local spinal and pelvic stabilizing muscles. The muscles here will be the transverse abdominus, diaphragm, posterior internal oblique, pelvic floor, and multifidus.

The Outer Unit

The ability for these muscles to work effectively requires stability in the previous inner unit.

The posterior oblique sling system comprises the lats, glute max, and thoracolumbar fascia, which work to extend the hamstrings over broad ranges.

The anterior oblique sling system is on the opposing side of the posterior oblique sling system, including the abdominal obliques, the adductors of the thigh, and the abdominal fascia.

The deep longitudinal sling system has the erector spinae, deep lamina of the thoracolumbar fascia, multifidus, and sacrotuberous ligament.

The lateral sling system is the outer unit’s final system and has the hip’s abductors, the quadratus lumborum, and the thigh adductors.

The inner and outer unit relationship proves that functional-based activities are a good idea.

Functional-based activities aim to improve the body’s ability to efficiently manage aspects of daily living, like physical activity, without undue resistance.

Common Postural Distortions and Muscle Imbalances

Some of the common causes of chronic postural distortion and muscular imbalances:

• Practicing poor posture at work or home
• Sedentary behaviors
• Repetitive training actions
• Poorly devised exercise programs
• Incorrect instruction or technique
• Injury-related movement compensations

Some common postural distortions are:

Winged scapula – this is shown with a lifted and outward rotation of the position of the scapula. The scapula will seem to protrude out posteriorly.

The upper crossed syndrome – is a distortion of the upper body that shows a forward head, raised and internally rotated shoulders, and an exaggerated thoracic curve.

Kyphosis – is excessive convex thoracic spine curves presenting as a bowed or rounded back.

Lordosis – excessive concave or inward curve in the lumbar spine.

Lower cross syndrome – lower body distortion shown with an unwanted anterior pelvis tilt.

Categories of Postural Distortions

We have the categories of upper body postural distortions, lower body postural distortions, and lower body distal extremity distortions.

The segmental problems, along with their related issues and limitations:

Forward Chin –

The overactive muscles are the trapezius, scalenes, sternocleidomastoid, and levator scapulae.

The underactive muscles are the serratus anterior, mid-low traps, and deep cervical muscles.

There is a major contribution here for upper cross and upper thoracic humps, limiting of the spine function, reductions in the complex shoulder efficiency, along with a range of motion.

Kyphotic exaggeration –

This is also known as the upper cross. The overactive muscles are the upper traps, pec muscles, subscapularis, lats, and teres major.

The underactive muscles are the rhomboids, mid-lower traps, teres minor, serratus anterior, infraspinatus, and posterior deltoid.

The limitations are shoulder complex dysfunction, impingement, and disturbances to the kinetic chain.

Lumbo-pelvic-hip postural distortion –

This is also called a lower cross syndrome.

The overactive muscles are the calves, hip adductors, hamstrings, erector spinae, rectus femoris, latissimus, and teres major.

The underactive muscles are the glutes, abdominals, and spinal stabilizers.

The limitations are hamstring strains, groin strains, and low back pain.

Lumbo-pelvic-hip postural distortion –

This is also called fixed lateral pelvic tilt.

The overactive muscles are the quadratus lumborum, iliopsoas, adductors, gluteus med, and the TFL.

The underactive muscles are the glute med, TFL, quadratus lumborum, erector spinae, and adductors.

These depend on the high and low sides.

The limitations present would be unilateral low and mid back pain, hamstring strains, adductor strains, IT band syndrome, and lateral hip pain.

Distal extremity postural distortion –

The overactive muscles are the calves, peroneals, posterior tibialis, adductors, iliotibial band, iliopsoas, and rectus femoris.

Possible limitations are plantar fasciitis, shin splints, and patellar tendonitis.

Corrective Exercise

Quantifying the Level of Dysfunction

The prioritization model is what is used to assess risk for training programs. This strategy first investigates the areas with the greatest level of need as a priority in the training program.

The needs analysis is an important inventory of adaptation needs for individuals, as found through screening and evaluation protocols. It can include identification, organization, and prioritization of physiological needs.

We usually find the primary limitation present, a significant issue that may involve pain and impedes overall function and performance. It needs immediate correction and emphasis. An example would be upper cross syndrome.

The secondary limitations are important to look at also. These issues may reduce one’s ability to perform tasks but do not cause major discomfort. An example would be slight tightness of the hamstrings.