Kinesiology of the Musculoskeletal System

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Kinesiology of the Musculoskeletal System

• Chapter 1

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What is Kinesiology ?

• kinesiology   n. Greek kinesis, movement
  -logy, science of.
• The study of the anatomy, physiology, and
  mechanics of body movement, especially in humans.
  
• -American Heritage Dictionary
• The branch of physiology that studies the
  mechanics and anatomy in relation to human
  movement
• -Merriam-Websters Medical Dictionary
• The study of muscular movement, especially the
  mechanics of human motion.
• - Stedman's Medical Dictionary

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Kinesiology

• A sound understanding of kinesiology allows for
  the development of a rational evaluation, a
  precise diagnosis, and an effective treatment of
  musculoskeletal disorders, and allows for safe,
  appropriate exercise prescription.
• The study of Kinesiology borrows heavily from the
  sciences of anatomy, biomechanics, and physiology
• Anatomy the science of the shape and structure
  of the human body and its parts
• Biomechanics a discipline that uses principles
  of physics to quantitatively study how forces
  interact with the living body
• Physiology the biologic study of living organism

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Kinesiology Terminology

• Kinematics a branch of mechanics that describes
  the motion of a body (the entire body or any of
  its parts or segments), without regard to the
  forces or torques that may produce the motion
• There are two general types of motions that occur
  within joints of the human body
• Translation linear motion in which all parts of
  a rigid body move parallel to and in the same
  direction as every other part of the body. Can
  occur in either a straight line or a curved line.
• Rotation motion in which an assumed rigid body
  moves in a circular path about some pivot point
  all points in the body simultaneously rotate in
  the same angular direction

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Kinesiology Terminology (cont.)

• Movement of the human body is often described as
  a translation of the bodys center of mass (COM)
• COM generally located just anterior to the sacrum
• Rotation occurs around an axis of rotation
  (AOR) an AOR is a non-anatomical point around
  which a rotating body moves
• Within most joint systems, AOR is located
• within or very near the structure of the
  joint
• however at times, the AOR can be located
• outside of the joint

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Kinesiology Terminology (cont.)

• Active Movement movement of a body (movement of
  a bone at a joint) that is caused by muscular
  contraction
• Passive Movement movement of a body caused by
  sources other than muscular contraction (i.e. an
  outside push or pull, gravity, etc.)
• Osteokinematics describes the motion of bones
  relative to the three cardinal planes of the
  body Sagittal, Frontal Horizontal

Cardinal Planes of Motion
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Kinesiology Terminology (cont.)

• Degrees of Freedom the number of independent
  movements allowed at a joint up to three degrees
  of angular freedom in the sagittal, frontal and
  horizontal planes.
• Clinically, the greater the degree of freedom
  (greater mobility) of a joint system, the greater
  degree of instability of that joint system.
• Outside movement in the three cardinal planes
  translation can occur. This movement within a
  joint is considered Accessory motion occurring
  at a joint.
• Clinical note This accessory motion is often
  assessed when determining the amount of
  instability within a joint, and when determining
  the extent of ligamentous damage sustained by a
  joint.

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Kinesiology Terminology (cont.)

• Osteokinematics A matter of perspective
• Movement of a joint can be considered from the
  perspective of either the proximal (close)
  segment or the distal (further) segment.

Femoral on Pelvic Motion
The proximal segment can rotate around the distal
segment when the distal segment is the relatively
stable segment. Likewise, the distal segment can
also rotate around the proximal segment when the
proximal segment is the relatively stable segment.
Pelvic on Femoral Motion
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Kinematic Chain

• Kinematic Chain a series of articulated
  segmented links, i.e. pelvis, thigh, leg, and
  foot
• Open Kinematic Chain a term used to describe a
  kinematic chain in which the distal segment is
  not in contact with the earth, or another
  relatively more stable object
• Closed Kinematic Chain a kinematic chain in
  which the distal segment is in contact with an
  object that is more stable than the body (i.e.
  ground)

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Closed or Open Kinematic Chains?
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Arthrokinematics

• Arthrokinematics the motion that occurs between
  the articular surfaces of a joint
• Arthrokinematics is largely dependent on the
  shape of the joint structures (shape of the bones
  within a joint)
• Arthrokinematic Principles of Movement
• Convex surface on a concave convex rolls and
  slides in the opposite direction
• Concave surface on convex concave member rolls
  and slides in simlar directions

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Arthrokinematics (cont.)

• There are three fundamental movements that occur
  within a joint
• Roll multiple points along one rotating
  articular surface contact multiple points on
  another articular surface
• Slide a single point on one articular surface
  contacts multiple points on another articular
  surface
• Spin a single point on one articular surface
  rotates on a single point on another articular
  surface

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Arthrokinematics (cont.)
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Closed Pack Loose Pack Positions

• Closed Pack Position the joint position of
  maximal congruency of its articular surfaces
• Usually found near the end of a joints Range of
  Motion (ROM)
• In the closed pack position, the joint ligaments
  and capsules are usually pulled taut
• The joint complex is more stable in this
  position, with less accessory motion
  (translation) occurring.
• Loose Pack Position all positions other than
  the closed pack position of a joint
• Ligaments and joint capsules are more slack
• Greater accessory motion

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Kinetics

• Kinetics the branch of mechanics that describes
  the effect of forces on the body
• Force a push or a pull that can produce,
  arrest, or modify movement
• Muscles are the force producers within the human
  body

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Stress Strain Curve

• Import curve here

Repetitive or prolonged stress at this strain
will eventually result in microdamage
(i.e. stress fracture)