Neuromuscular ConceptsSeminar @ ABOW Winter 2010

SOMATIC SENSORY SYSTEM

I. Background

A. Differences between somatic senses and other senses

– 1. Receptors are distributed throughout the body as opposed to being concentrated at small, specialized locations.

– 2. Responds to many kinds of stimuli (usually mechanical)– 3. At least four (4) senses (not one)

• a. Temperature• b. Body position• c. Touch• d. Pain

– 4. Place, pressure, sharpness, texture, and duration can

be accurately gauges.

B. Types of somatic sensation receptors

– 1. Mechanoreceptors--sensitive to physical distortion (touch)

– 2. Nociceptors--respond to damaging stimuli (pain)

– 3. Thermoreceptors--sensitive to changes in temperature

– 4. Proprioceptors--monitor body position

– 5. Chemoreceptors--respond to certain chemicals

II. TYPES OF RECEPTORS

Mechanoreceptors

• a. Pacinian– i. Sensitive to vibration (250-350 Hz)– ii. Involved in the fine discrimination of texture or other moving stimuli

that cause vibrations

• b. Meissner's corpuscle– i. Most common receptor in glabrous skin (smooth, hairless)– ii. Sensitive to vibration (low frequency, 30-50 Hz)

• c. Ruffini's ending– not well understood

• d. Mercel's disks– i. Light pressure and tactile discrimination

• e. Hair follicle receptor

Proprioceptors

• a. Body position– i. Where the body is– ii. Direction of movement– iii. Speed of movement

• b. Receptors in the skeletal muscles

• Two different mechanosensitive proprioceptors:– i. Muscle spindles-consist of specialized intrafusal muscle

fibers distributed among ordinary (extrafusal) muscle fibers; detect changes in muscle length.

– ii. Golgi tendon organs-distributed among collagen fibers in tendons and detects changes in muscle tension.

Muscle Structure

GTO

INTEGRATED TRAINING CONCEPTS

Integrated Training Concepts

Integrated training is comprehensive training approach that strives to improve all components necessary to allow a client to achieve optimum movement. Muscles work in integrated groups to provide neuromuscular control during functional movements. Muscles have the ability to dominate certain planes of motion; however, the centralnervous system is designed to optimize the selection of muscle synergies, not the selection of individual muscles.

• Multiple systems work interdependently to allow structural and functional efficiency. Functional strength is the ability of the neuromuscular system to perform dynamic eccentric, isometric and concentric actions efficiently in a Multi-planar environment. If any of these systems do not work efficiently, compensations and adaptations occur in other systems. These compensations and adaptations lead to tissue overload, decreased performance and predictable patterns of injury.

Neuromuscular efficiency is the ability of the neuromuscular system to enable muscle actions to work synergistically; to work concentrically, eccentrically and dynamically stabilize throughout the entire kinetic chain in all three planes of motion.

FORCE PRODUCTION BY MUSCLES

Intramuscular coordination

Motor unit recruitment. All muscle fibers are grouped together as motor units (Mu). A motor unit is a nerve and all the muscle fibers innervated by the nerve. All the muscle fibers in a motor unit are the same type.If the fibers are slow twitch in a motor unit the unit is considered a low threshold unit. This unit requires light tension for recruitment.

When the fibers are fast twitch within the unit it is considered a high threshold unit. Heavy tension is required for the recruitment of high threshold Mu's.

When a motor unit is sufficiently activated the entire pool of fibers contract. If the message from the nerve is too weak nothing happens.

This is called the all or none principle. Increasing the number of units recruited greatly increases strength. Beginners usually have little success in recruiting numerous motor units. Advanced athletes have the capabilities of recruiting multiple Mu's, which increases force production.

Rate coding• The firing rate of motor units usually increases with training.

This is called rate coding. When a muscle fiber is stimulated it twitches. With increasing nervous system stimulation the twitches begin to overlap.

• When this happens rate coding is in action, which causes increased force production.

• When intensity levels are between 50-80% of 1RM increased motor unit recruitment is the main contributor to strength increase.

• When the intensity level reaches between 80-100% of 1RM in a given movement, the main contributor to increasing force production is the increased firing rate of motor units.

Intermuscular coordination

• This refers to the bodies ability to maximize the synergist effects that varying muscles display in order to perform a movement.

TREATMENT CONCEPTSKinetic Chain Concepts

• Treatment involves normalizing the dysfunctional states

• Deactivating trigger points within the dysfunctional muscles or trigger points that maybe influencing them.

• Normalizing short and/or weak muscles

• Reeducating posture and body usage

Reorganizing Inappropriate Firing Sequences • Seen when synergists adopt the role of prime

mover in important movement patterns. This alters the order in which muscles contract and leads to poor coordination between prime movers, synergists and antagonists.

• The most characteristic feature is substitution; (Synergistic Dominance) which alters the entire pattern.

Definition of Joint Stability

• "The effective accommodation of the joints to each specific load demand through an adequately tailored joint compression, as a function of gravity, coordinated muscle and ligament forces, to produce effective joint reaction forces under changing conditions. Optimal stability is achieved when the balance between performance (the level of stability) and effort is optimized to economize the use of energy. Non-optimal joint stability implicates altered laxity/stiffness values leading to increased joint translations resulting in a new joint position and/or exaggerated/reduced joint compression, with a disturbed performance/effort ratio.

Analysis of Neuromuscular Function

• Analysis of neuromuscular function will require tests for both motor control (timing of muscle activation) and muscular capacity (strength and endurance) since both are required for intersegmental or intrapelvic control, regional control (between thorax and pelvis, pelvis and legs) as well as the maintenance of whole body equilibrium during functional tasks.

Treatment Concept

• Treatment protocols should include techniques to foster normal length tension relationships.

MUSCLE SPINDLE CELL TECHNIQUE

Muscle Spindle Cell Technique

• Located in the belly of the muscle, the spindle cell monitors the muscle’s length and rate of change in length (rate of stretch). They help the brain control how the muscle functions, keeping it in balance with its antagonist.

– Facilitates Prime mover– Facilitates Synergists– Facilitates Stablizers– Inhibits Antagonists

Muscle Spindle Cells

Every muscle has spindle cell proprioceptors, which sends information to the brain about a muscle’s length and tension. They are locate throughout the muscle, but are more concentrated in the belly of the muscle. Depending on the way that we manipulate the propioceptor, we can increase or decrease the muscles level of facilitation.

Procedure 1

To Facilitate (to strengthen)

With your thumbs or fingers quickly apply medium pressure at the belly of the muscle and pull towards the ends of the muscle. The spindle cells will now send a message to the brain that the muscle is to long. The brain responds by sending nerve impulses to the muscle causing it to shorten. As a result the muscle strengthens.

Procedure 2• To Inhibit (to weaken)

With your thumbs and fingers, quickly apply medium pressure at the belly of the muscle and push towards the center of the muscle. The spindle cells will now send a message to the brain that the muscle is to short. The brain responds by sending nerve impulses to the muscle causing it to lengthen. As a result the muscle weakens.

• This technique is indicated in any traumatic injury.

GOLGI TENDON TECHNIQUE

Golgi Tendon Technique

• Located in the ends of the muscle near the tendons, the spindle cell monitors the tendon’s length and rate of change in length (rate of stretch). They help the brain control how the tendon functions. If the tendon has too much tension, the golgi cell warns the brain to keep the muscle from tearing.

– Inhibits Prime Mover– Inhibits Synergists– Facilitates Antagonist

Golgi Tendon Receptors

• Every tendon has golgi cell proprioceptors, which sends information to the brain about a tendon’s length. They are locate near the tendon of the muscle.

• Depending on the way that we manipulate the propioceptor, we can increase or decrease the muscles level of facilitation.

Procedure 1

• To Facilitate (to strengthen)

With your thumbs and fingers, quickly apply medium pressure at the tendon of the muscle and push towards the center of the muscle. The golgi cells will now send a message to the brain that the tendon does not have enough tension. The brain responds by sending nerve impulses to the muscle causing it to shorten. As a result the muscle strengthens.

Procedure 2

To Inhibit (to weaken)

With your thumbs or fingers quickly apply medium pressure to the tendon of the muscle and pull towards the ends of the tendon. The golgi cells will now send a message to the brain that the muscle has too much tension. The brain responds by sending nerve impulses to the muscle causing it to lengthen. As a result the muscle weakens.

• This is not a common finding.

• This technique is indicated in any traumatic injury.

Spindle cells and Golgi cell proprioceptors work in opposite ways.

Note

Summary of Key Kinetic Chain Concepts

• Proprioception– Cumulative neural input to the central nervous system from all mechanoreceptors of

the entire kinetic chain.

• Mechaneoreceptors– Highly specialized neural structures that convert mechanical information into

electrical information that is relayed to the central nervous system.

• Length-Tension Relationship– Muscles can only produce optimal force from its optimal length.

• Force-Couple Relationship– Muscles work in synergies to reduce force, dynamically stabilize and produce force.

• Synergistic Dominance– The process whereby synergists compensate for a weak or inhibited prime mover in

attempts to maintain force production and functional movement patterns.

• Reciprocal Inhibition– The process whereby a tight or overactive agonist inhibits its functional antagonist.

• Muscle length tension relationships

• Muscles function optimally from a predetermined length, thus an optimal length tension relationship.

• This decreases force production and alters force couple relationships.

• Muscle tightness can cause reciprocal inhibition and synergistic dominance.

 • The speed of muscular exertion during functional movements is limited by

the neuromuscular system.

• Reactive Neuromuscular Training – heightens the excitability of the central nervous system.

• Stabilization strength, core strength, and neuromuscular efficiency control the time between eccentric contraction and the subsequent concentric contraction. (Stiffness)

• Most injuries occur as a result of repetitive end-range loading. Tissue protection occurs when agonist/antagonist muscles are co-activated to maintain control of tissues within the physiological range and avoid harmful end-range loading while maintaining the centrated position of joints. Joint centration is the point of equilibrium or maximum congruence for optimization of handling joint loading.

• The ability of muscles to achieve and maintain centration concerns both coordination and endurance functions.

Holistic Approach to Rehabilitation

• To promote or restore joint stability, rehabilitation of the muscular system is necessary. This requires a holistic approach emphasizing the functional role of muscles in maintaining dynamic joint stability while producing the movements which are required by our activities of daily living. This functional role views muscles as working together in chains to perform functional activities, rather than as individual muscles having the classical roles expressed as their actions.

Types of Muscular Dysfunction• The muscular system can respond to trauma,

repetitive overload, pathology or pain in a variety of ways. Muscles can become facilitated, overactive and even shortened in length, or they can become inhibited, weakened and atrophic. Individual muscles function in concert with entire groups of muscles throughout the body to maintain stability or produce movement. These individual muscles may be classified as agonists, synergists or antagonists. When any muscle's function is disturbed (i.e., facilitated or inhibited), movement and stability throughout the entire kinetic chain will be affected.

• The development of predictable muscle imbalances is further spurred by the diminished afferent flow of sensory information from the periphery, in particular the sole of the foot, due to sedentarism and a lack of variety of movement. Naturally, movement patterns are altered and fatiguability increased, thus rendering the motor control system less able to adapt to various biomechanical sources of repetitive strain.

• Regardless of the type of muscle dysfunction, rehabilitation of dynamic joint stability necessitates that equilibrium be restored. This requires improving endurance of the muscle system and also the coordination of agonist-antagonist co-activation which guides movement so that the "neutral range" of joints are controlled and repetitive end range overloading is minimized.

General Progression of Care

• The general progression of care when treating locomotor system dysfunction is to begin with treatment of the core structures which are dysfunctional, then progress to include treatments which restore muscle balance (endurance, flexibility, coordination, etc.), and finally attempt to achieve improved motor control on a subcortical, automatic basis.

• Muscle imbalances once formed are easily perpetuated by reciprocal inhibition. The tighter muscles continuously inhibit their weakened antagonists, thus perpetuating the problem. Additionally, it is the overactive muscles, which are regularly trained by most exercise routines unless specific attention is paid to isolating the inhibited "weak link." Janda has always maintained that tight or overactive muscles should be relaxed or stretched (neuromuscularly) before initiating a strengthening routine or else the muscle imbalance will only be reinforced.10 Stabilization exercise programs place a great emphasis on conscious control of posture during exercise so as to carefully isolate the inhibited muscles and thus avoid encouraging inappropriate muscle substitution and faulty movement patterns.

Muscles of the stabilization mechanism

• Lumbo-Pelvic Hip Complex – CORE – muscles that originate or insert into the lumbar spine

– TVA– Multifidi– Internal oblique– Transversospinalis– Diaphram– Pelvic floor muscles

 • Movement systems – superficial musculature

that attaches to the rib cage from the pelvis and/or lower extremity.

Muscles of the Movement System

– Rectus Abdominus– External Obique– Erector Spinae– Hamstrings– Quadriceps– Gluteus Maximus– Latissimus Dorsi– Adductors– Abductors

 • They transfer and absorb forces from the upper and

lower body to the pelvis

• Comprised of four working subsystems; force couples: Operating as an integrated functional unit.

• Remember that the central nervous system is designed to optimize the selection of muscle synergies.

• In order to more effectively understand motion and design efficient training, reconditioning and rehabilitation programs it is imperative to view muscles functioning in all planes of motion.

Multi-segmental functional relationships in the

kinetic chain.

• The kinetic chain functions synergistically to eccentrically decelerate (reduce force), isometerically stabilize (dynamically) and concentrically to accelerate (produce force) movement in all three planes of motion and in all joints of the kinetic chain.

• If a change occurs in alignment at one joint, changes in alignment of other joints must occur.

• Remember that all these changes are bi-directional.

Key Concept

• A lack of understanding of the synergistic function of muscles of the kinetic chain in all three planes will lead to a lack of optimum performance and potential of developing muscle imbalances.

Muscle Action Classification• Agonist – muscles that act as prime movers

• Antagonist – muscles that act in direct opposition to prime movers

• Synergist – muscles that assist prime movers in a movement pattern

• Stabilizers – muscles that support or stabilize while performing movement patterns

• Neutralizers – muscles that counteract unwanted actions of other muscles

Serial Distortion Patterns

• are the state in which the functional and structural integrity of the kinetic chain is altered and in which and adaptations occurs.

Common Serial Distortion Patterns

– Upper extremity postural distortion- Upper cross

– Lower extremity postural distortion – Lower cross

– Lumbo-Pelvic-Hip postural distortion- Pronation Distortion

FOUR WORKING SUB-SYSTEMS

LS – Lateral Subsystem

• Responsible for pelvo-femorial stability

• Dysfunction leads to increased pronation

LS – Lateral Subsystem

– Gluteus Medius/Minimus

– Adductor Complex contralateral

– Quadratus Lumborum

DLS – Deep Longitudinal Subsystem

• Activation increases tension in the sacrotuberous ligament, which transmits forces across the sacrum allowing forces to be transferred up the erector spinae group to the upper body

DLS – Deep Longitudinal Subsystem

– Erector Spinae Group

– Thoracolumbar Fascia

– Sacrotuberous Ligament

– Biceps Femoris

– Soleus

POS – Posterior Oblique Subsystem

• Provides transverse plane stabilization to the sacroiliac joint

• Distributes transverse plane forces created through rotational activities

POS – Posterior Oblique Subsystem

– Latissimus Dorsi contralateral

– Thoracolumbar Fascia

– Gluteus Maximus contralateral

AOS – Anterior Oblique Subsystem

• Provides transverse plane stabilization

• Provides dynamic stabilization to the Lumbo-pelvic hip complex

AOS – Anterior Oblique Subsystem

– Internal Oblique and Adductor Complex contra-lateral

– External Oblique and External Hip Rotators

– Transverse Abdominis

• Each subsystem individually and interdependently contributes to the production of efficient movement; by accelerating, decelerating and dynamically stabilizing the kinetic chain during motion.