Kinesiology Introduction: Chapter 1-4
Introduction to Kinesiology
Defining Kinesiology: The study of movement which integrates several disciplines:
Anatomy: The study of body structures (bones, muscles).
Physiology: The study of how those structures move and function.
Physics and Mechanics: Essential for understanding the principles of movement and how the body works in conjunction.
Clinical Application: Professionals study kinesiology to understand body limitations, energy sources, and neurological pathways.
Neurological Example: If a patient reports tingling specifically in the pinky finger, it indicates an issue with the ulnar nerve, as it is the only nerve affecting that specific area of the hand.
Roles in Therapy: While a supervising Occupational Therapist (OT) sets the overall goals, the Occupational Therapy Assistant (OTA) decides the specific treatment approach based on kinesiological knowledge.
Fundamental Concepts of Mechanics
Biomechanics: The application of mechanical principles to human movement (how muscles are used to create motion).
Mechanics: The study of how force is exerted on an object.
Kinematics: The study of the motion of a body without regard to the forces and torques that cause the motion.
Kinetics: Describes the effects of forces on the body and how those forces result in movement or resistance.
Torque: A twisting or rotational force (e.g., using a torque wrench to remove lug nuts from a tire).
Kinematic Classifications
Arthrokinematics: Movement that occurs at the joint surfaces (joint-level movement).
Movement Types: Includes rolling, gliding, and sliding.
Clinical Example: Spinal movements often involve these gliding interactions between surfaces.
Osteokinematics: Movement of the bones in space.
Terms: Flexion, extension, abduction, adduction, medial (internal) rotation, and lateral (external) rotation.
Kinetic Chain: A series of connected limb segments where movement in one area influences others.
Equilibrium and Posture: The body tends to follow the head. Looking at the feet while walking causes the shoulders to dip, the spine to curve forward, and the hips to rotate anteriorly to compensate.
Closed Kinetic Chain: The distal segment is fixed while the proximal segment moves (e.g., hand against a wall while the shoulder moves).
Open Kinetic Chain: The distal segment is free to move while the proximal segment is fixed (e.g., sitting and kicking a foot).
Planes of Motion and Axes of Rotation
Sagittal Plane: Divides the body into left and right portions.
Midsagittal: Cuts directly through the center.
Axis: Frontal (Anterior-to-Posterior pin).
Movements: Flexion and extension.
Frontal (Coronal) Plane: Divides the body into front and back portions (metaphor: Han Solo frozen in carbonite or a pane of glass).
Axis: Sagittal.
Movements: Abduction and adduction.
Horizontal (Transverse) Plane: Divides the body into upper (superior) and lower (inferior) portions.
Axis: Vertical.
Movements: Medial and lateral rotation.
Degrees of Freedom and Range of Motion (ROM)
Degrees of Freedom: The number of planes in which a joint can move.
Uniaxial: One plane, one axis, one degree of freedom (e.g., the elbow, which only performs flexion/extension).
Biaxial: Two planes, two axes, two degrees of freedom (e.g., the wrist).
Triaxial: Three planes, three axes, three degrees of freedom (e.g., shoulder and hip joints).
Range of Motion (ROM): The total amount of motion a joint can move in any direction. * Importance: Critical for documenting patient progress for insurance purposes; progress must be shown through numeric data.
Goniometry: The measurement of joint angles.
Tools: Large goniometers for shoulders/knees; tiny ones for hand joints (DIP and PIP joints).
Components: A stabilizing arm and a moving arm.
Dynamics and Statics
Statics: Study of systems in a constant state of motion or rest.
Clinical Evaluation: Standing balance tests (closing eyes to remove visual input, narrowing base of support) and static sitting balance.
Dynamics: Study of systems in motion (kinetics and kinematics).
Stabilizers: Muscle contractions that maintain position against external forces (e.g., holding an arm against a wall).
Dynamic Evaluation: Tossing a ball to a patient to force movement outside their base of support, requiring compensatory muscle reactions.
Scalar vs. Vector Quantities
Scalar: Magnitude only (e.g., speed, length, area, volume, mass).
Vector: Magnitude and direction (e.g., force, velocity, acceleration).
Clinical Documentation: Notes must include both (e.g., " resistance to flexion for 15 repetitions"). Measurements/reps are necessary to provide a "just right challenge" for the patient.
Forces in Kinesiology
Internal Forces: Muscle contractions.
External Forces: Gravity, weights, or physical resistance.
Gravity: Acts directly downward. It must be considered in safety, such as preventing patients from falling forward out of wheelchairs.
Friction: Resistance to motion between two surfaces. Increased by compression; decreased by traction. Friction generates heat and can cause inflammation.
Linear Force: Forces acting along the same line (same or opposite direction).
Parallel Force: Forces in the same plane that can be in same or opposite directions.
Force Couple: Two or more parallel forces acting in different directions to produce rotation (e.g., the scapula rotating clockwise or counterclockwise).
Concurrent Force: Multiple forces acting on the same point at the same time, resulting in a resultant vector.
Specific Stress Forces
Traction (Distraction): Joint surfaces pulling apart (e.g., spinal decompression). It allows bulging discs to retract and promotes nutrient flow.
Manual Application: Often used for neck pain management.
Caution: Popping joints releases gas bubbles (instant relief), but over-rotation of the neck can stretch arteries and lead to a stroke.
Compression: Pushing joint surfaces together (e.g., weight-bearing exercises to improve proprioception).
Shear: Parallel surfaces sliding across one another. Discs can handle downward pressure but are easily injured by shearing (e.g., twisting side-to-side with heavy weights).
Bending: Compression on the concave side and traction on the convex side.
Torsion: A twisting force involving two opposing rotations.
Torque and Levers
Torque Formula: . * Torque (T): The tendency of a force to produce rotation around an axis. * Moment Arm: The perpendicular distance between the line of force application and the axis of motion.
Leverage: Applying force further from the axis (distally) increases torque (e.g., using a "cheater bar" on a tire iron or using a jar-opening grip tool).
Newton's Laws of Motion:
1. Law of Inertia: An object stays at rest or in motion unless acted on by an external force (e.g., gravity stopping a ball).
2. Law of Acceleration: . A lighter ball (tennis ball) moves further/faster than a heavy ball (bowling ball) if the same force is applied.
3. Law of Action/Reaction: For every action, there is an equal and opposite reaction.
Stability and Balance
Center of Gravity (COG): The point where the mass and weight of the body are balanced.
Base of Support (BOS): The contact area with the surface. A wide BOS (feet shoulder-width apart) is more stable than a narrow one.
Line of Gravity: An imaginary vertical line from the COG to the ground. * Plumb Bob: An archaeology tool used to check vertical alignment; also used to assess spinal alignment.
Stability Principles: Stability increases with a larger BOS, lower COG, COG remaining within the BOS, greater mass, and greater friction.
Simple Machines and Motion Types
Linear Motion: All parts move in the same direction at once.
Curvilinear Motion: Motion in a curved path (e.g., skiing).
Angular Motion: Movement around a fixed point (axis). Only the joint acts as the axis.
Levers:
1st Class: Axis is between force and resistance (e.g., head balancing on the first cervical vertebra).
2nd Class: Resistance is between axis and force (e.g., wheelbarrow). Force arm stays longer than the resistance arm (Mechanical Advantage).
3rd Class: Force is between axis and resistance (e.g., bicep curl). Most common in the human body. Resistance arm is longer than the force arm.
Pulleys: Used to change the direction of force.
Human Body Example: The malleolus (the ankle bone) acts as a pulley for the tendons/muscles.
Inclined Planes: A ramp makes movement safer and easier for wheelchair users by working with gravity rather than against a vertical step.
Joint Specifics and End Feel
Carpal Bones: There are 8 carpal bones in the wrist; they interact via gliding motions.
Hinge Joint: Uniaxial (e.g., the elbow where the ulna—with its "U" shaped notch—fits into the humerus).
Saddle Joint: Biaxial (e.g., the CMC joint of the thumb; concave and convex surfaces fit together like a rider in a saddle).
Ball and Socket: Triaxial (e.g., hip joint).
End Feel: The sensation felt at the end of a joint's passive ROM.
Hard (Bony): Bone hitting bone (e.g., elbow extension).
Soft: Muscle tissue approximation (e.g., bicep curl).
Abnormal: Caused by pain or substantial swelling (edema), which may prevent accurate goniometry measurements.
Introduction to Kinesiology
Defining Kinesiology: The study of movement which integrates several disciplines:
Anatomy: The study of body structures (bones, muscles).
Physiology: The study of how those structures move and function.
Physics and Mechanics: Essential for understanding the principles of movement and how the body works in conjunction.
Clinical Application: Professionals study kinesiology to understand body limitations, energy sources, and neurological pathways.
Neurological Example: If a patient reports tingling specifically in the pinky finger, it indicates an issue with the ulnar nerve, as it is the only nerve affecting that specific area of the hand.
Roles in Therapy: While a supervising Occupational Therapist (OT) sets the overall goals, the Occupational Therapy Assistant (OTA) decides the specific treatment approach based on kinesiological knowledge.