2/5/23 KINETICS

• WHAT IS KINETICS?

  deals with forces that produce, stop or modify motion of body as a whole or individual body segments
• FORCES EXTERTED IN KINETICS ARE?

  Gravity, Muscles, Friction, External Resistance
• What anticipates and understands how to use movement to influence outcomes?

  Laws of Motion
• What is the displacement of body of one of its segments from one point to another?

  Motion
• What produces force to move our bodies?

  Muscles
• What are the determinants of motion?

  1. Type of Motion
  2. Location of Motion
  3. Magnitude of Motion
  4. Direction of Motion
  5. Rate of Motion
• What is the movement in a straight line?

  Translatory Motion; Linear Displacement
• If you reach across the desk for a pencil, the forearm is moving in a straight line while the shoulder rotates, what are the type of motions present?

  Translatory-Rotatory;
• What is the movement of a rigid segment around an axis?

  Rotatory Motion; Angular Displacement
• What determines true rotatory motion?

  a fixed axis so each part of the rigid segment moves through the same angle at the same time
• The body movement is a combination of what motions?

  linear and rotatory
• What is the motion of a body or segment when force is applied?

  Displacement
• What is the push or pull that produces displacement?

  Force
• What are the two dimensions of force?

  Magnitude and direction
• What is the state of a system that is balanced because both forces are equal?

  Equilibrium
• What are the 4 types of forces?

  • Gravity
  • Muscles
  • Externally applied resistances
  • Friction
• What class lever gains force or distance, depending on the relative lengths of the force arm and resistance arm?

  Class 1 lever

  • if both equal forces with equal lever arm lengths or product of force, the system is in equilibrium
  • examples: SEESAW, atlanto-occipital joint (axis), weight of the head (resistance) by neck extensor muscle force.
• What class lever wherein the lever arm of resistance is shorter than the force lever arm?

  Class 2 Lever

  • provide a mechanical advantage so large weights can be supported by a smaller force
  • examples: wheelbarrow (weight load is closest to wheels), standing on the balls of feet
• Which class lever is most common in the human body?

  Third
• Which class lever has longer resistance arm than force arm?

  Class 3 Lever

  • mechanical advantage lies within resistance arm
  • produces speed of distal segment; connected to open kinematic chain
• Examples of an open-chain motion?

  • The deltoid acting on the glenohumeral joint to elevate the arm from the side
  • The flexor digitorum profundus closing the interphalangeal joints around a ball
  • The extensor carpi radialis extending the wrist in a wave
• If the axis is central, what type of level class?

  Class 1
• If the resistance is central, what type of lever class?

  Class 2
• If the force is central, what type of lever class?

  Class 3
• What refers to the ratio between the length of the force arm and length of the resistance arm?

  Mechanical Advantage
• What is the equation for MA?

  MA = Force Arm Length / Resistance Arm Length

  • the higher the quotient of the ratio, the greater the MA.
• What are the types of muscle activation?

  Isometric

  Concentric

  Eccentric

  Isotonic

  Isokinetic
• When a muscle produces force with no apparent change in joint angle, what is the activation?

  Isometric

  • static, holding, contractions
  • stabilizes joints
  • example: reaching forward with the hand, scapula must be stabilized against thorax
• Concentric = positive
• Eccentric = negative
• When a muscle shortens, what is the activation?

  Concentric Activity

  • proximal and distal insertion points move closer
  • acceleration of body segments
  • example: rising from a chair or lifting a glass of water to mouth
• When a muscle lengthens. what is the activation?

  Eccentric Activity

  • muscle points of insertion move away from each other
  • against gravity
  • decelerates body segments
• When a muscle detached from the body and lifts a load vertically against gravity, what is the activation?

  Isotonic

  • shortening of the muscle
  • load on muscle is constant
• When a contraction that has a constant rate of movement, what is the activation?

  Isokinetic

  • contracting a muscle group without permitting acceleration to occur
  • ISOKINETIC DYNAMOMETER
• Proximal Attachments = Origin
• Distal Attachment = Insertion
• What type of attachments move toward fixed distal attachments?

  Proximal (CKC)
• What segment does the force of gravity help out in movement?


  Distal
• What are the three aspects of Muscle Functional Activity?

  • Agonist
  • Antagonist
  • Synergist
• Which muscle is the principle muscle producing a motion or maintaining a posture?

  Agonist

  • actively contracts to produce a concentric, eccentric, or isometric contraction
  • prime movers