Clinical Kinesiology & Biomechanics – Comprehensive Study Notes

Definition of Kinesiology

• Study of human movement

• The study of muscles, bones, and joints as they are involved in the science of movement

• Discipline that focuses on movements during human physical activity

Biomechanics vs Kinesiology

• Biomechanics includes: applied physical education, exercise physiology, athletic training, sport history, pedagogy, sport philosophy, sport art, sport psychology

• Kinesiology includes motor behavior

• Relationship: Biomechanics often emphasizes quantitative analysis of movement; kinesiology emphasizes broader study of movement including qualitative aspects

Definition of Biomechanics

• The study of the movement mechanics of living organisms

• Application of mechanical principles to living organisms, such as humans

Biomechanics vs Kinesiology: Quantitative vs Qualitative

• Biomechanics typically emphasizes quantitative analysis

• Kinesiology often emphasizes qualitative aspects of movement

Kinematics vs Kinetics; Functional Anatomy (Page 7 concept)

• Kinematics: Linear components such as Position, Velocity, Acceleration

• Kinetics: Forces and Torques

• Functional Anatomy: angular and linear aspects of movement; integration of anatomical structures with movement

• Human Movement Analysis combines these perspectives to understand how structure and forces produce movement

Introduction to Biomechanics: Core ideas (Page 8)

• Movement is a core function; impairment can arise from injury or pain

• Clinicians (therapists, surgeons, etc.) use biomechanics to understand terminology (e.g., moment)

• Biomechanics is important for clinicians to understand how the musculoskeletal system functions

• Useful for critically evaluating current or new patient evaluations and treatments

Interrelationships among Structure, Force, and Movement (Page 9–10)

• Two general factors govern movement: structure composition and applied forces

• Principle: form/shape of a biological structure is influenced by its function

• Interdependence among three elements: Structure → Movement; Movement → Forces; Forces → Structure

• Function = purposeful application of movement and depends on the interaction of structure, force, and movement

• Clinicians need to understand these interrelationships to design and direct interventions to restore or optimize movement

• Requires a detailed image of regional structure and grasp of the laws of motion and tissue material properties

Why Study These Rules? (Page 11–12)

• To help people move better, improving performance or reducing injury risk

• “Performance” can mean different things: higher jump, farther throw, or reducing energy cost of walking

• Reducing injury risk: mechanopathology = loads on the body that a structure is not designed to handle

• Pathomechanics = injury or disease changes how a person moves when attempting to work around the condition, potentially placing improper loads on structures

• External/environmental factors (e.g., slippery floors, opponent contact) can be injurious

Who Needs to Know Biomechanics? (Page 13)

• Anyone involved with movement

• Physical educators, personal trainers, athletic trainers, physical therapists, chiropractors, physicians

• Ergonomists or engineers involved in equipment design

• Orthopedic surgeons involved in structural modification or repair

Principles of Biomechanics (Page 14–15)

• Mechanical: rules of motion derived from physics/classical mechanics

• Multisegmental: the body is composed of multiple connected segments; coordinated action (e.g., throwing involves lower extremities, trunk, and upper extremities)

• Biological: humans are living organisms; cannot violate the laws of physics; force production depends on anatomy/physiology of muscles; many factors influence force production

• Newton’s Second Law reference: the source of the force in $F = ma$ is your muscles

Osteology (Page 16)

• The study of bones and skeleton structure

The Human Skeleton (Pages 17–20)

• Composed of axial and appendicular skeletons

• Functions of the skeleton:

  • Support to maintain posture

  • Movement by serving as attachment points for muscles and acting as levers

  • Protection of vital soft tissues (heart, lungs, brain)

  • Storage for minerals (calcium, phosphorous)

Axial Skeleton (Page 18)

• 80 bones

• Components: Skull, Spinal column, Sternum, Ribs

Appendicular Skeleton (Page 19–20)

• 126 bones

• Components: Bones of upper and lower extremities; includes girdles (shoulder and pelvic) and limbs

Types of Bones (Pages 21–28)

• Long bones

  • Cylindrical shaft with wide ends; length > width

  • Largest bones; major levers

  • Examples: Femur, Tibia, Fibula, Humerus, Radius, Ulna

• Short bones

  • Roughly equal dimensions; cubical shape; large articular surfaces

  • Often articulate with more than one bone; provide some shock absorption

  • Examples: Carpals, Tarsals

• Flat bones

  • Broad, often curved surfaces; provide protection

  • Examples: Scapula, Sternum, Clavicle, Ribs, Ilium, Parietal and Frontal bones of the skull

• Irregular bones

  • Do not fit other categories; complex shapes

  • Examples: Vertebrae, Sacrum, Pubis, bones of the face

• Sesamoid bones

  • Sesame-seed shaped; located where tendons cross ends of long bones

  • Protect tendons from wear, change tendon attachment angle, improve mechanical advantage

  • Examples: Patella; sesamoids in flexor hallucis longus and thumb tendons

Directional Terminology (Pages 29–36)

• Anatomical Position (reference standard):

  • Standing erect, eyes forward, arms at sides, palms facing forward, feet parallel

• Fundamental Position: similar to anatomical position but arms relaxed, palms inward

• Directional terms (examples):

  • Anterior (ventral): toward the front; e.g., breast is anterior to shoulder blade

  • Posterior (dorsal): toward the back; e.g., spine is posterior to the umbilicus

  • Superior (cranial): toward the head; e.g., lungs are superior to the stomach

  • Inferior (caudal): away from the head; e.g., ankle is inferior to the knee

  • Medial: toward the midline; e.g., nose is medial to eyes

  • Lateral: away from the midline; e.g., hips are lateral to the belly button

  • Proximal: nearest the trunk attachment

  • Distal: farther from the trunk attachment

Coordinate Systems, Planes of Motion, and Planes/Axes (Pages 37–55)

• Frame of reference: fixed Earth reference is used for biomechanical analysis

• Coordinate system with anatomically aligned axes: medial/lateral (ML), anterior/posterior (AP), superior/inferior (SI)

• Planes of Motion (cardinal planes):

  • Sagittal Plane: divides body left-right; movements occur in this plane; formed by SI and AP axes

  • Frontal (Coronal) Plane: divides body anterior-posterior; movements occur in this plane; formed by SI and ML axes

  • Transverse (Horizontal) Plane: divides body superior-inferior; movements occur in this plane; formed by AP and ML axes

• 3D Cartesian coordinate system (origin at the center of mass in the anatomical position):

  • x-direction: anterior–posterior

  • y-direction: medial–lateral

  • z-direction: superior–inferior

• Axes of Rotation (rotation occurs perpendicular to the plane of motion):

  • Imaginary line through the center of an object around which rotation occurs

  • For a given plane, rotation occurs about an axis that is 90° to that plane

Axes of Rotation (Pages 49–56)

• Mediolateral axis (coronal/frontal axis):

  • Runs side to side (left-right)

  • Perpendicular to the sagittal plane

  • Rotations around this axis are sagittal-plane movements (flexion/extension)

• Anteroposterior axis (sagittal axis):

  • Runs from front to back (anterior–posterior)

  • Perpendicular to the frontal plane

  • Rotations around this axis are frontal-plane movements (abduction/adduction)

• Longitudinal axis (vertical axis):

  • Runs top to bottom (superior–inferior)

  • Perpendicular to the transverse plane

  • Rotations around this axis are transverse-plane movements (internal/external rotation)

Planes of Motion and Axis Relationships (Page 48–55)

• Rotation about an axis produces motion in a plane perpendicular to that axis

• Example: flexion/extension typically occurs about a mediolateral axis in the sagittal plane

• Abduction/adduction occur about an anteroposterior axis in the frontal plane

• Internal/external rotation occur about a longitudinal axis in the transverse plane

3D Coordinate System and Planes (Page 46)

• Start with an origin at the center of mass (COM) of the body in the anatomical position

• Establish axes: x (anterior–posterior), y (medial–lateral), z (superior–inferior)

• This framework allows a complete description of movement in 3D space

Types of Motion (Pages 57–61)

• Linear (Translational) Motion

  • Movement in a straight line from one location to another

  • All body parts move the same distance in the same direction at the same time

  • Subtypes: Rectilinear motion (straight line) and Curvilinear motion (curved path)

• Angular (Rotational) Motion

  • Movement of an object around a fixed point

  • All parts move through the same angle, in the same direction, at the same distance from the axis of rotation

  • Can be with respect to internal or external axis of rotation

• General Motion

  • A combination of linear and angular motions; most human movement is general motion

• Active and Passive Motions

  • Active: caused by muscle activity

  • Passive: caused by ligamentous tension, joint reaction forces, and external forces (e.g., gravity)

• Osteokinematics and Arthrokinematics

  • Osteokinematics: voluntary movement between two bones (primary/physiologic motion)

  • Arthrokinematics: involuntary movement between joint surfaces needed for normal range of motion (secondary/joint play)

Clinical Scenarios and Applications (Pages 63–65)

• Pathomechanics vs Mechanopathology (Page 63)

  • Example question: A patient with left hip pain alters gait to spend less time on the affected side

  • Correct concept: Pathomechanics – injury or disease changes how movement occurs as the person tries to work around the condition

  • Mechanopathology: certain ways of moving place loads the body was not designed to handle

• Patellectomy and Tendon Mechanics (Page 64)

  • Total patellectomy reduces force production across the patellar tendon; the patella is a sesamoid bone

  • Effect: changes the angle of attachment of the patellar tendon, altering mechanical advantage and force transmission

• Movement Analysis Exercise (Page 65)

  • Task: Analyze the movement of the left upper arm around the shoulder joint during a wall push-up in terms of direction, plane, and axis of rotation

  • Likely analysis (based on standard biomechanics):

  • Direction: shoulder flexion/extension (phase-dependent; advancing toward flexion during effort to push away from the wall)

  • Plane of motion: Sagittal plane

  • Axis of rotation: Mediolateral axis (frontal axis)

Quick Reference: Summary of Key Concepts

• Structure–Function–Movement Interdependence: form is shaped by function; movement affects forces; forces modify structure

• Mechanopathology: inappropriate loads on tissues due to movement patterns

• Pathomechanics: movement adaptations due to injury/disease

• Planes and Axes: three cardinal planes with corresponding axes of rotation; movements occur in these planes around the respective axes

• Osteokinematics vs Arthrokinematics: primary vs secondary joint motions

• Sesamoid bones: small bones that modify tendon paths and leverage (patella is the classic example)

• Newton’s Law in biomechanics: $F = m a$ where muscle force is the source of acceleration

• Comprehensive biomechanical analysis requires understanding anatomy (bones, joints, muscles) and physics (motion, forces, lever systems)