Download Integrated Function of the Kinetic Chain

Chapter 5
Human Movement Science
Objectives
• After this presentation, the participant will be able to:
– Describe biomechanical terminology, planes of motion,
axes, joint motions, muscle actions, and how they relate to
the kinetic chain.
– Describe how forces act on the HMS and influence
movement.
– Provide an overview of motor behavior.
– Describe the importance of sensory information as it
relates to movement.
Human Movement System
Function
• The Human Movement System must:
– Be aware of its relationship to its
environments, both internal and external.
– Gather necessary information regarding them.
– Produce appropriate motor responses.
– This ensures optimum functioning of the HMS
and optimum human movement.
Biomechanics
• Applies principles of physics to understand
how the human body moves.
• Terminology
– Important to understand basic anatomic
terminology
• Allows for effective communication
Anatomic Locations
• Superior refers to a position above a reference
point
• Inferior refers to a position below a reference point
• Proximal refers to a position nearest the center of
the body or point of reference
• Distal refers to a position farthest from the center of
the body or point of reference
• Anterior refers to a position on the front or toward
the front of the body
Anatomic Locations
• Posterior refers to a position on the back or toward
the back of the body
• Medial refers to a position relatively closer to the
midline of the body
• Lateral refers to a position relatively farther away
from the midline of the body or toward the outside of
the body
• Contralateral refers to a position on the opposite
side of the body
• Ipsilateral refers to a position on the same side of
the body
Planes, Axes, and Joint Motion
• Three imaginary planes are positioned through
the body at right angles, intersecting at the
center of mass of the body.
• Movement is said to occur more predominantly
in a specific plane if it is actually along the plane
or parallel to it.
• Movement in a plane occurs about an axis
running perpendicular to that plane.
• Anatomic position, is reference position
Planes, Axes and Joint Motion
• Sagittal plane bisects body
into right and left sides, occurs
around coronal axis, flexion &
extension (ex. Hip extension)
• Frontal plane bisects body into
front and back halves, occurs
around anterior-posterior axis,
abduction & adduction (ex.
Shoulder abduction)
• Transverse plane bisects the
body into upper and lower
halves, occurs around vertical
axis, internal & external rotation
(ex. spinal rotation)
• Use the book to study all joint
motions.
Planes, Axes and Motion
• Horizontal abduction- movement of a limb
in transverse plane from an anterior to
lateral position
• Horizontal adduction-movement of the arm
or thigh in the transverse plane from a
lateral position to an anterior position.
Scapular Motion
A. Scapular retraction- occurs
when the shoulder blades
come closer together.
B. Scapular protraction-occurs
when the shoulder blades
move further away from each
other.
C. Scapular depression-occurs
when the shoulder blades
move downward, whereas
D. Scapular elevation-occurs
when the shoulder blades
move upward toward the ears.
Muscle Actions
• Muscles produce a variety of actions known as the
muscle action spectrum to manipulate forces.
– Eccentric
• Lengthening of the muscle
• Force reduction
• Ex. Gluteus Maximus eccentrically flexes the hip
– Isometric
• No appreciable change in the muscle length
• Dynamically stabilize the body
• Ex. Gluteus Maximus isometrically stabilizes the hip
– Concentric
• Shortening of the muscle
• Force production
• Ex. Gluteus Maximus concentrically extends the hip*
Functional Anatomy—Muscles
• The traditional perception of muscles is
that they work concentrically and
predominantly in one plane of motion.
• It is imperative to view muscles functioning
in all planes of motion and through the
entire muscle contraction spectrum
(eccentrically, isometrically, and
concentrically).
Muscle Force
• Force is defined as the interaction between two
entities or bodies that results in either the
acceleration or deceleration of an object.
• When muscular force is generated, the resulting
movement is rotation at the joint. The term for
rotational force is called torque.*
• The fitness professional must gain an understanding
of the different kinetic chain components involved to
efficiently produce force and movement.
Length–Tension Relationships
•
The length at which a muscle can
produce the greatest force
– There is an optimal muscle length
at which the actin and myosin
filaments in the sarcomere have
the greatest degree of overlap.
– Lengthening a muscle beyond this
optimal length and then stimulating
it reduces the amount of actin and
myosin overlap, reducing force
production.
– Shortening a muscle too much and
then stimulating it places the actin
and myosin in a state of maximal
overlap and allows for no further
movement to occur between the
filaments, reducing its force output.
– When a muscle is tight or
shortened due to adhesions and
alters the way normal movement
occurs this is called an Altered
Length Tension Relationship. Ex.
Feet turn out and put the Gluteus
Maximus in a position that
generates less force.*
Force–Velocity Curve
• Refers to the ability of
muscles to produce
force with increasing
velocity
– As the velocity of a
concentric muscle
contraction increases, its
ability to produce force
decreases.
– As the velocity of an
eccentric muscle
contraction increases, its
ability to produce force
increases.
Force–Couple Relationships
• A force–couple is synergistic
action of muscles to produce
movement around a joint.
– Common Force–Couples
• Internal and external obliques
rotate the trunk.
• Upper trapezius and lower
portion of the serratus anterior
rotate the scapula upward.
• Gluteus maximus, quadriceps,
gastrocnemius, and soleus
produce hip, knee, and ankle
extension.
– All muscles working together for
the production of proper movement
are said to be working in proper
force–couple relationships.
Muscle Leverage and
Arthrokinematics
• Amount of leverage the kinetic
chain has for any given
movement depends on the
leverage of the muscles in
relation to the resistance.
– The closer the weight is to the
joint, the less torque it creates
and the easier it is to lift.
– The farther away the weight is
from the joint, the more torque
it creates and the harder it is to
lift.
Muscle Synergies
• Muscles are recruited by the
central nervous system (CNS)
as groups or synergies.
– Over time and through proposed
stages of learning, these synergies
become more fluent and
automated.
• Squat: Quadriceps,
hamstrings, gluteus
maximus
• Shoulder Press: Deltoid,
rotator cuff, trapezius
Proprioception
• The cumulative neural input from the sensory
afferents to the central nervous system
– Uses information from mechanoreceptors (muscle, tendon,
ligament, and joint receptors) to provide information about
static, transitional, and dynamic position, movement, and
sensation pertaining to muscle and joint force.
– A vital source of information that the nervous system uses
to gather information about the environment to produce the
most efficient movement.
Sensorimotor Integration
• The ability of the nervous system to gather
and interpret sensory information to
anticipate, select, and execute the proper
motor response
– There has to be a perceived reason to
activate muscle tissue for the reduction or
stabilization of forces imposed on the body, or
for the production of force to overcome
imposed forces on the body.
– Achieved through the task of collecting and
then interpreting all incoming sensory
information.
Sensorimotor Integration
• Only as effective as the quality of incoming sensory
information
– The skeletal system must be properly aligned to allow the
muscles to be positioned at the right length–tension
relationships.
• This is known as structural efficiency.
– Proper structural alignment puts the body in the correct
position to efficiently absorb, distribute, and produce
forces.
• This is known as functional efficiency.
• Any deviation in the alignment of the kinetic chain
causes altered sensory input that results in an
altered motor response.
Feedback
• The use of sensory information and
sensorimotor integration to aid the kinetic
chain in the development of permanent
neural representations of motor patterns.
– Internal
– External
Internal Feedback
• The information coming back to the central
nervous system from all sensory receptors
(proprioception).
– Also known as sensory feedback
• Incoming (afferent) feedback is by the central
nervous system to monitor movements and their
outcomes, provide information about the
environment, and allow for any necessary
adjustments to be made.
• When a client feels a change in their
environment it is considered Internal Feedback.*
External Feedback
• Information provided by some external source such as a
fitness professional, videotape, or a heart rate monitor.
– Also known as augmented feedback.
• Provides clients with an external source of information
that allows them to associate how the achieved
movement pattern was (“good” or “bad”) compared with
what they are “feeling.”
External Feedback
• Two major forms
– Knowledge of Results
• Used after the completion
of a movement to inform
clients about the outcome
of their performance.
– Knowledge of Performance
• Provides information about
the quality of the
movement pattern.
• Clients must not become
dependent on external
feedback, especially from the
fitness professional, as this
may detract from their
responsiveness to the internal
sensory input.
Summary
• Each system of the human movement system
(HMS) is interdependent.
• The entire HMS must work together to gather
information from internal and external environments
to create and learn movements (motor behavior).
• The body uses proprioception, sensorimotor
integration, and muscle synergies to create efficient
movement (motor control).
• Repeated practice, as well as internal and external
feedback, allows this efficient movement to be
reproduced (motor learning).