Kinesiology and Biomechanics

Kinesiology

• Study of movement
• Includes principles of mechanics, anatomy, and neuromuscular physiology
• Involves analyzing motion
• Describes how the patient is moving

Biomechanics

• Mechanical principles applied to the human body
• Dynamic systems involve moving systems
• Static systems involve non-moving systems

Kinetics

• Force causing movement
• Muscles generate force

Kinematics

• Time, space, and mass aspects of moving systems
• Physics involved

Key Terms

• Lateral: Away from the midline
• Medial: Toward the midline
• Proximal: Toward the trunk
• Distal: Away from the trunk
• Ventral/Anterior: Front of the body
• Dorsal/Posterior: Back of the body
• Superior: Upper surface
• Inferior: Lower surface
• Caudal: Closer to the feet
• Cranial/Cephalad: Closer to the head

Joint Motions in the Shoulder

• Flexion
• Extension
• Internal rotation
• External rotation
• Abduction
• Adduction
• Horizontal abduction
• Horizontal adduction

Scapular Motions (Shoulder Girdle)

• Elevation
• Depression
• Protraction/Abduction
• Retraction/Adduction
• Upward rotation
• Downward rotation

Joint Motion in Elbow

• Flexion
• Extension

Joint Motion in Forearm

• Supination
• Pronation

Joint Motions in Wrist

• Flexion
• Extension
• Radial deviation (thumb)
• Ulnar deviation

Joint Motions in Fingers

• Flexion
• Extension
• Abduction
• Adduction
• Thumb opposition

Joint Motions Upper Extremity

• Hip motions are similar to shoulder motions
• Knee motions similar to elbow motions
• Ankle involves dorsiflexion, plantarflexion, eversion, and inversion

Planes of Motion

• Divisions of the body
• Describes the axis of rotation for joint motion

Frontal/Coronal Plane

• Divides the body into anterior and posterior sections
• Most common movements are abduction and adduction

Sagittal Plane

• Divides the body into left and right sections
• Most common movements are flexion and extension

Transverse Plane

• Divides the body into upper and lower sections
• Most common movements are internal and external rotation and horizontal abduction/adduction

Types of Linear Motion

• Describing movement of translation in a line from one location to another

Rectilinear Movements

• Occurs in a straight line from one location to another
• All parts move in the same direction at the same time

Curvilinear Movement

• Occurs in curved line from one location to another
• All parts move in the same direction at the same time

Linear Motions

• Involves a whole body movement made from angular motions

Angular Motions

• All parts move at the same angle, in the same direction, at the same time
• Do not travel the same distance
• Joint specific
• Goniometry measures angles at joints

Rotational Motions

• Movement occurs around a vertical or longitudinal axis

Osteokinematics

• Describes movement of bones around the joint axis
• Refers to names to describe joint motion with joint motion with flexion and extension
• Can be seen and measured

Arthrokinematics

• Movements within the joint
• Intra-articular motion
• Happens inside the joint, not seen on the outside

Types of Joints

• Fibrous joints
• Suture joints (synarthrosis)
  • Occur only in the skull
  • Feature fused bones
• Ligamentous joint
  • Ligaments hold the joint together
  • Allow small amounts of movement
  • Example: Distal radio ulnar joint
• Gomphosis
  • Involves interlocking
  • Example: teeth
• Cartilaginous joints
  • Absorb shock and allow for some motion
  • Provide stability
  • Examples: Vertebral discs and Sternoclavicular joint
• Synovial joints
  • Feature no direct contact between bone ends
  • Contain a joint capsule
  • Have a capsule filled with synovial fluid
  • Mobile

Classifications of Synovial Joints

• Classified by number of axes, kind of joint motions, and degree of freedom
• Degree of freedom is defined as number of planes in which a joint can move
• Nonaxial joints
  • Have small amounts of linear motion, lacking angular motion
  • Gliding motion usually occurs
  • Examples: Costovertebral and Intervertebral joints
  • Have no degrees of freedom
• Uniaxial joints
  • Hinge joints allow only flexion and extension
  • Pivot joints allow only rotation
  • Have 1 degree of freedom
• Bi Axial joints
  • Saddle joints, like the Thumb CMC joint
  • Allow 2 degrees of freedom
  • Allow Flexion, extension, Abduction and adduction
• Tri-axial joint
  • Ball and socket type joint
  • Allow 3 degrees of freedom
  • Allow Flexion, extension, Abduction, adduction and rotation

Joint Structures

• Ligaments connect bone to bone
• Tendons connect muscle to bone
• Cartilage
  • Articular cartilage (Hyaline) covers ends of bones and has a smooth and slick surface
  • Fibrocartilage (meniscus, disks, labrum) provides shock absorption
  • Elastic cartilage (found in the ear larynx) can stretch and resume shape
• Aponeurosis
  • A flat tendinous sheet, like the latissimus dorsi

Bursae

• Pad like sacs around most joints where friction is the greatest

Arthrokinematics

Arthokinematics

• Describes how adjoining joint surfaces move on one another
• Describes Intra-articular motion (inside the joint)
• Dictated by joint surface shape
• Accessory motion is involuntary and has 2 types: joint play and component movement
• Joint play happens due to an external force
• Externally applied, gliding, sliding, spinning rolling
• Joint mobilization improves ROM
• Component movement accompanies osteokinetic motion to allow full ROM
• Internal movements that are required for orthokinetic
• Example: Upward rotation of scapula with shoulder abduction and flexion

Joint Surface Shape

• Ovoid joints are the most synovial joints
• Articulating bones have a convex/concave
• Sellar or saddle joints
  • Each joint surface is concave in one direction and convex in another

Types of Motion

• Roll describes rolling of one joint surface on another
• Roll involves new points on each surface coming into contact throughout motion
  • Examples:
  • Ball rolling across the ground
  • GH joint
• Glides/slides
  • Describe the linear movement of a joint surface parallel to the adjoining joint surface
  • One point on a joint surface contacts new points on the adjoining joint surface
    • Example: Ice skater, blade (one point), across the ice (many points)
• Spin
  • Rotation of joint surface on fixed adjacent surface
  • Same point on each surface remains in contact with one another
    • Example: Top spinning on a table Bicep femoris during knee extension and hip flexion

Concave-Convex Rule

• This rule does not change based on the joint
• Concave joint surface
  • Will move on a fixed convex surface in the same direction as the body part that ismoving Convex joint surface
• Will move on a fixed concave surface in the opposite direction of the body part
  • Example: Hip abduction- femur rolling superiorly and gliding inferiorly on a fixed acetabulum

Joint Congruency

• Joint surface positions
• Congruent joint surfaces have maximum contact, are tightly compressed and known as closed packed or close packed position
• Usually occurs at one extreme of ROM
• Closed pack position
  • Ligaments and capsules are stretched positions
  • Provides stability to joint
• Joints are more prone to injury in closed packed position
• Incongruent joint surfaces are is not a maximum contact position known as open packed or loose packed position or resting position
  • Capsule and supporting ligaments are lax
  • Passive separation of joint surfaces can happen in this position
  • Joint mobilization is performed in these positions

Arthrokinematics

• Accessory motion forces and joint mobilization
  • forces are externally applied
• Three types used in joint mobilization
  • traction
  • compression
  • shear
  • Bending and Rotary (want to avoid)

End Feels Of A Joint

• The feel of a the tissue when passively moving to the end of a joint's ROM.
• A subjective assessment of quality of joints feel
• Normal vs pathological

Normal End Feels

• Bony (hard) end feels
  • Hard and abrupt limit to motion
  • Bone to bone contact at the end of the range
  • Example: Elbow extension
• Capsular ends feel
  • Leather-like with give at the end of PROM
  • Results from limitation of the joint capsule tissues
  • Normal example- shoulder flexion and abduction
  • Pathological ends feel
  • Empty ends or excessive pain, No resistance to movement

Muscular System Attachments

• Muscle tissue contracts without regard for direction

Origin

• Typically, the end attachment to the more stable bone
• Muscle usually moves toward the insertion site

Insertion

• The end attached to the more mobile bone

Reversal of Muscle Action

• Describes the situation when the origin moves towards the insertion
• Happens when the usual insertion site (bone/body part) is more stable
• Push ups

Muscle Fiber Arrangements

• Two basic muscle fiber arrangements: parallel and oblique
• Parallel
  • Usually allows great ROM and less strength
  • Strap
    • Long and thin fibers that run the entire muscle length; typically, muscles are long and tendons are short
    • Example: Sternocleidomastoid
  • Fusiform
    • Spindle shaped, attached to tendons
    • Not all fibers run length of muscle, longer tendons and shorter muscles
  • Rhomboidal
    • Typically four sided and flat
  • Triangular
    • Flat and fan shaped, narrow attachment at one end and broad at the other
• Oblique
  • Allows shorter movements but has more strength potential and less ROM
  • Feather like (pennate)
  • Unipennate
    • Looks like a half of feather
    • Example: Central tendon (flexor pollics)
  • Bipennate
    • Looks like whole feather
    • have Central tendon (interosseous)
  • Multipennate
    • Many fibers with oblique tendons in between
    • Example: Deltoid

Muscle Tissue Characteristics

• Resting position
  • Length of muscle at rest when it is unstimulated
• Irritability
  • Muscle's ability to respond to stimulus
• Contractility
  • Ability of muscles to contract or shorten
  • If muscles aren't irritable, they won't contract
• Extensibility
  • The ability to stretch or lengthen in response to force
• Elasticity
  • Ability to rebound to the resting length after removal of force
  • PROM

Types of Muscle Tension

• Flacidity is when there is no tension.
• Passive tension is the force that comes from non-contractile units of the muscle (like stretching a rubber band).
• Active tension is the force that comes from the contractile units of muscle (like releasing one side of the rubber band).

Muscle Tone

• A slight tension present when the muscle is at rest.
• Normal tone reflects the muscle's state of readiness.
• Abnormal tone refers to high (spasticity) or low tone.
• High tone muscle fires constantly (CP).
• Low tone can be caused by stroke or arms dangling.
• Tone is associated with CNS disorders.

Excursion

• A muscle's total length between its maximally shortened and maximally stretched lengths.
• There is an optimum range in which every muscle contracts most effectively. This is why MMT has specific guidelines. Without adequate excursion, full joint ROM cannot be achieved.

Length-Tension Relationship

• Multijointed surfaces have a length-tension relationship
  • Active Insufficiency: The inability of a muscle to shorten enough to cause full ROM simultaneously at both joints.
    • For example, in order to flex the hip, extension must be present at the Knee
• This means, the inability to lengthen to provide full range of motion at both joints.

Muscle Contraction

• Better contractile ability or better tension when muscle is elongated or stretched before contraction
• Length tension relationship is optimized in two joint or multip joint muscles (hamstring action when climbing stairs)

Types of Muscle Contractions

• Isometric*
  • No joint movement
  • Isotonic:
  • Joint movement
    • Concentric: - Shortening contraction
      • Muscle attachments move closer together
        • Movement occurs against gravity
        • Acceleration activity
      • Eccentric:
        • Lengthening contraction
        • Muscle attachments move farther away
        • Movement occurs with gravity
        • Deceleration activity - Isokinetic:
      • Resistance changes throughout ROM

Roles of Muscles

• Agonist: The prime mover that causes a motion.
• Antagonist: The muscle that performs the opposite motion of the agonist.
• Synergist: A muscle that works with other muscles to enhance motion.
• Co-contractor: When agonist and antagonist contract at the same time.
• Stabilizer: A group of muscles that provides support so that the agonist is more effective.
  • Neutralizer:
  • Prevents unwanted movement

Kinematic Chains

• Open chain
  • Distal end is free to move in space.
• Closed chain
  • Distal end is fixed.
• Length of kinematic chain= Number of joints involved throughout completing a particular activity.
• Unilateral- Means on ones side of the body, while Ipsilateral means the body is on the same side and Contralateral is the joint is on the opposite side