module 2 lesson 3: understanding kinetic chain and human function

directionally-

- The global system responds more slowly and is therefore ? dependent . - Individuals with dysfunction demonstrate inefficiency at the local level, ultimately affecting the global level. - These individuals present with an increased risk for injury and reduced performance relative to movement potential.

- range of motion - anticipatory

- local stabilizers do not control ?, but rather prepare a body segment for oncoming force through a mostly isometric contraction. - Therefore, they function in an ? manner, preceding movement, impact or a loading condition

delayed local system firing

? allows forces to go unmanaged and can lead to injury

familiarity and rehearsal

? and ? is key in the process of improving function and motor patterning.

The interaction between structures of the musculoskeletal system

? dictates the proficiency of movement.

Muscle contractions

? make up for deficiencies in structural form, adding to stabilization and energy transfer in a joint, such as the shoulder, or joint system, such as the spine.

Local

? systems pertain to those essential to segmental stability; these smaller, internally-located muscles aid the ligaments in holding bony segments in place.

motor learning (This explains why practice improves performance. Laymen refer to this concept as "muscle memory," but, in fact, it is nervous system recall, as muscle tissue is useless without direction from the CNS)

A body well-acquainted with a particular environment can more effectively control its actions when encountering this familiar scenario. This is often referred to as ?, as the nervous system learns intelligently by rehearsing movement or actions within a specific environment.

emotion

A fourth component of human function stems from the psychological orientation involving

stabilize, neutralize, accelerate, or decelerate

A muscle may need to ? x4 a body segment depending on the action(s) performed

Isometric contraction -

A type of muscle contraction providing for no change in a joint angle; a static muscle contraction.

articulating surfaces

All joints maintain a level of form closure via contact support between

potential force

Any loss of energy along the kinetic chain reduces the ? applied at the point of contact

Form closure Force closure Motor control Emotion

Components of the integrated model of function:

- accelerate - decelerate - stabalize

Concentric contractions ? movement, eccentric contractions ? movement, and isometric contractions ? or neutralize a joint position to manage energy efficiently

- Identifies the relationship between the brain and working muscles during physical actions - Emotion is physically expressed: can lead to postural adjustments, promote biomechanical changes (e.g., unnecessary tension), and impact focus - Affects motivation which affects force production - Has the greatest impact on finite actions (e.g., putting during golf) - The use of targeting, location stimuli, and other focal interactions with trained movements to stimulate the brain can improve focus, and therefore performance

Describe Emotion:

The slow-twitch muscles that provide stability to the joint segments do so by firing earlier than the fast-twitch fibers of the global system. This allows the local system to anchor a motion segment before the global system pulls upon it

Due to the anticipatory response and early activation in local stabilizers, a significant neurophysiological difference exists in the timing of contractions between the local muscle system that stabilizes the spine (inner unit) and the global muscle system that acts upon it. - explain this

psychomotor-dependent

Focus is integral to technique and execution and is ?, which clearly identifies the intimate role of the brain and muscle tissue in physical actions

deficiency of form closure

Force closure supports the ? by increasing compressive force across the joint surface to counter any offsetting forces. The quantity of force closure needed to adequately ensure support is a product of the individual's form closure and the overall magnitude of the load

integrity of associated tissues

Form and force closure also depend upon the ?. When connective tissues are healthy, elastic, strong, and force-balanced there is limited disruption to an area, suggesting no undue resistive stress. When agonist and antagonist muscles lose their functional relationship, or tissues shorten, the internal environment experiences added stress, and these musculoskeletal changes will, over time, offset the skeletal position.

Passive system - form closure Active system - force closure Control system - neural activation and coordination

Functional recruitment for stability and efficient movement occurs through the coordinated actions of three systems:

global movers (mobilizers)

Global system muscles may aid in stability through phasic actions or function as ? , depending on variables such as the type of action or direction of forces.

in a phasic manner, suggesting the activation is not constant but, rather, cooperative with other muscles

Global system musculature fosters regional stability and motion and tends to function . . .

feed-forward postural response

In healthy individuals, the activity of the trunk musculature precedes that of the muscle(s) responsible for limb movement, thus contributing to what is referred to as the ?

rapid contractions

In normal function, local stabilizers perform ? to anticipate multi-directional limb and trunk movements, such as a running back changing direction. (unpredictable loading) This also occurs under conditions of predictable loading in a system where the local stabilizers function normally, such as a back squat

unexpected perturbations

In the spine, anticipatory actions prepare the vertebrae for ?, regardless of the direction of the movement

its prime mover role; however, these tissues account for a number of actions beyond simply accelerating linear movement in a single plane, as seen in a leg extension.

Inexperienced personal trainers often oversimplify the function of a muscle to ?

local and global systems of kinetic chain

Interaction between structures of the musculoskeletal system which manage force transfer for efficient movement

- Local systems function in an anticipatory manner before movements/loading to brace the joint or body segment and maximize stability (very important for protecting the spine) - Local systems fire earlier than the fibers of global systems to anchor a motion segment before the global system pulls on it for bodily movement - Activity of local systems in the trunk should precede that of muscles responsible for limb movement (feed-forward response)

Local and global systems cooperate for movement efficiency and reduce the risk for injury via several mechanisms:

role-specific and segment translation (or articular sliding)

Local stabilizing systems tend to be more ?. - They are continuously active throughout a movement, often across a *single joint*, functioning to reduce ?

predictable and unpredictable loading

Local-global cooperation must occur during both ? scenarios or performance will suffer

cause or resist movement

Most people think of muscles only as movers, but the role of muscle contractions extends well beyond the need to produce force for acceleration alone. Motor control implies the regulation of internal forces created to either ?. This is supported by the different types of contractions and their timing.

exposure to an environment or a condition

Motor control develops through continued ?

central nervous system (CNS)

Recruitment patterns are harmonized via the ? so that energy/force is transferred fluidly across joint segments (as shown with the tennis player)

global stabilizers

Some global system muscles aid in stability during actions

Postural syndromes

Static or dynamic malalignment of one or more skeletal segments.

static positioning and dynamic actions

The body does not function in isolation; it integrates mechanisms to manage forces for both ?

close-packed position

The joint most efficiently resists shear stress when the joint angle reaches a ?, as it has maximized both congruence of the articulating surface and tension of associated ligament

form closure is reduced

When joints are misaligned, the support of ?, placing increasing demands on soft tissues for force closure to maintain the same level of stability

to promote or resist movement

While the interplay of connective tissue is relevant, the muscular system possesses the greatest potential ?

Muscles and joints

blank and blank must interact cooperatively and synergistically to properly move and stabilize the body during physical activity

activity is direction dependent and activity is non continuous

characteristics of global mobilizers

- fulfill proprioceptive functions - activity is independent of the direction of movement - activation is continuous in nature but reactive to offset forces

characteristics of local stabalizer

- Refers to neuromuscular activation within motor units to produce movement via appropriate force - The magnitude of force and the timing of motor unit activation/deactivation dictate stability - Familiarity and movement practice (rehearsal) is key to improving motor control - Practice improves performance = layman's understanding of "muscle memory"

describe Motor control:

- Simply put, the trunk must first brace, creating stability at the joints of the spine to supersede any material force that will be placed upon them. This provides for adequate rigidity during the encounter with the global forces - On the other hand, when these muscles experience a delayed firing response, forces go unmanaged, ultimately leading to injury

describe feed froward response

- Includes ligaments, tendons, muscle, and fascia that provide support and stability - Force closure supports any deficiency in form closure via muscular contractions and connective tissue compressive forces - Lack of stability in a joint reduces force production (weakest link in kinetic chain)

describe force closure

- Describes the structural aspects of the body and the specific architecture of joints; defining characteristics of joints stem from their structure, orientation, and shape: - If the segments fit together like a puzzle, significant support is provided (hip) - If the connecting surface area is limited, other tissues enhance stability (shoulder)

describe form closure

the energy derives from ground reaction forces that must transfer from the feet through the legs to the hips; this energy then accelerates through the trunk and transfers across the shoulder to the arm, ultimately manifesting in the hands at the racquet

describe the kinetic chain of energy when a person swings a tennis racquet

Integrated model of function

describes the cooperation and coordination between bodily systems

Form closure:

efficiency of joint structures; primarily consists of bones and connective tissues - joint anatomy, alignment, and mobility

local muscle systems

essential for localized joint stability and neutral joint positioning

- transverse abdominis - pelvic floor - diaphragm - multifidus - posterior fibers of interior obliques - vastus medialis - supraspinatus -soleus

example of local stabalizers

- external obliques - rectus abdominis - erector spinae - psaos major - Latissimus dorsi - gluteus maximus - hip adductors - hamstrings -gastrocnemius

examples of global mobilizers

- quadrates lumborum - psaos major - external and internal obliques - rectus abdominis - hip adductors - trapezius - levator scapulae - serratus anterior - rhomboid

examples of global stabalizers

bones, joints, and connective tissues

form closure frames the human machine, including the ? that support and move the body. Whereas bones and connective tissue form all joints, the defining characteristics of individual joints stem from their structure, orientation, and shape

produce joint movement especially movement in the sagittal plane; tend to contract concentrically and absorb shock impact from forces

function of global mobilizer

- control inner and outer range of movement - tend to contract eccentrically for low load deceleration of momentum and for rotational control

function of global stabalizer

- control neural joint position - contraction does not produce change in muscle length or movement

function of local stabilizer

activity is direction dependent; activation is non-continuous

global stabilizer characteristics

- increase muscle stiffness to control segmental movement

role of local stabilizer

form closure

how well a joint aligns

joints will suffer from undue stress and movement proficiency will be lost

if muscles do not fire in synch or compensatory actions occur due to neuromuscular inefficiency, what will happen?

motor control

neuromuscular coordination

emotion

one's current psychological orientation which can impact neural activity

global mobilizers

other global system muscles aid in function as movers

-Hamstrings - Rectus Abdominis - Latissimus Dorsi

phasic and postural muscles of the spine: global mobilizers

-Internal Obliques - Spinalis - Gluteus Medius

phasic and postural muscles of the spine: global stabilizers

- Transverse Abdominis - Deep Lumbar - Multifidus - Supraspinatus

phasic and postural muscles of the spine: local stabilizers

Kinetic chain:

refers to the force across body segments or chain of force transfer involved in properly moving the body

global muscle systems

responsible for motion and regional stability that tend to function in a phasic manner (transfer force across body segments and joints)

generate torque to produce movement

role of global mobilizer

- motor control - force closure - form closure

stability is made up of what three things

Dysfunction -

suggests reduced performance efficiency and injury risk due to musculoskeletal deficiencies that create poor posture, faulty movement patterns, and/or incorrect biomechanics

Function -

suggests the body can manage environments and conditions efficiently, without undue stress or restriction

Force closure:

support of soft tissues which help maintain joint position; primarily consists of muscles and fascia - muscular stiffness, appropriate contraction, and myofascial synergy

timing of activation and deactivation

the ? of motor units provides motor control not the magnitude of a force applied. When the timing of contractions counters offsetting forces, the body becomes more efficient at producing desired outcomes.

force closure

the ability of connective tissue to maintain joint positional alignment

low form closure

the connecting surface area limits the joint's form closure by placing greater reliance on additional tissues to provide stability, as in the case of the glenohumeral joint of the shoulder - because of this the shoulder has low

high form closure

the hip joint fitting together very well indicates

motor control

the proficiency of the neuromuscular system to anticipate and react to external stimuli

sticking point:

the resistance is harder to move at certain joint angles due to inefficiency in the acting joints' stability and mechanical disadvantage.

- adequate mobility - muscle balance - passive and active elements of stabilization - effective muscle activation - optimal neuromuscular coordination

training for improved function focuses on:

- joint angles: *a closed-packed position is most efficient at resisting stress // changes in stability demands during a movement can create a sticking point* - connective tissue integrity: *limited disruptive stress occurs when tissues are healthy and mobile* - muscle balance: *agonist- antagonist imbalance increases stress / imbalances can offset bone and joint alignments or result in postural distortions*

what are factors that impact force closure

1. muscoskeletal system maintains proper symmetry for appropriate form and force closure 2. activation is orderly and efficient with proper anticipatory signaling 3. local stability balance is attained through appropriate agonist and antagonist muscle relationships acting upon each joint 4. overall force development occurs without restriction through effective force couples, resulting in energy conservation during static and dynamic activities

what does it mean to suggest a person is functional?

generate force to control range of motion

what is the role of a global stabalizer