Biomechanics Overview Quiz

Biomechanics Overview

• Biomechanics is the study of motion and its causes in living tissues (human and animal)
• It provides conceptual and mathematical tools for understanding how living things move
• It helps professionals improve movement and make it safer
• It gives key information on the most effective and safest movement patterns, equipment, and exercises for human movement improvement.
• Physical educators, coaches, athletic trainers, and physical therapists use biomechanics to analyze movement and treat injuries.

Subdivisions of Biomechanics

• Biomechanics encompasses the study of living things (systems or tissues) using the science of mechanics.
• Mechanics is the study of motion and how forces create motion.
• Biomechanics investigates the structure and function of biological systems using the methods of mechanics.
• It examines internal and external forces acting on the human body and their effects.
• Forces in living things can: create motion, promote growth and development, and cause injury due to tissue overload.

Orthopedic Biomechanics

• Ortho: perpendicular or correct "straight" and pedic ("child"), dealing with correcting and preventing deformities in children.
• Orthopedic: deals with bone and musculoskeletal disorders.
• Bio: relates to living systems and tissues.
• Mechanics: science of motion and force.
• Force and motion play a crucial role in living systems.
• Orthopedic biomechanics focuses on motions and forces within the human musculoskeletal system.

Areas of Study and Research in Biomechanics

• Sport and Exercise Science
• Coaching
• Ergonomics (equipment design)
• Gait and Locomotion
• Orthopedics and rehabilitation (physical and occupational therapy)
• Prosthetics and Orthotics
• Motor Control
• Computer Simulation
• Video Games (example: FIFA)

Biomechanics in Diverse Fields

• Exercise and sport biomechanics improves athletic performance and reduces injuries, including identification of risk factors and prevention programs (ACL, landing strategies).
• Study of the changes in joint biomechanics after injuries to create appropriate rehabilitation programs.
• Orthopedic biomechanics focuses on improving functional movement capacity through artificial limbs, joints, and orthoses, studying natural and artificial biological tissues for treatment or repair.
• Occupational biomechanics utilizes ergonomics and human factors to reduce workplace injuries.
• Comparative biomechanics examines different biological systems like swimming in fish, locomotion in apes, and horse and dog racing performance .

Applications of Biomechanics

• Engineers and occupational therapists design work tasks and assistive equipment to prevent overuse injuries related to specific jobs (e.g. helmets for preventing head injury in vehicles).
• Design and manufacture of prosthetics and artificial limbs.
• Prescribing rehabilitative exercises, assistive devices or orthotics to correct deformities and support function.

Biomechanical Testing and Evaluation

• Biomechanical testing identifies abnormal movement patterns and altered neuromuscular strategies in musculoskeletal or neurological injuries that cannot be fully captured through standard clinical evaluations.
• Such advanced testing has clinical applications in improving injury predictions for patients at high risk.
• Examine the complex functions of the human musculoskeletal system, considering the role of bony segments, joint connective tissue, and muscles, and external forces applied on these structures.
• Human motion is inherently complex, involving multiple segments and forces often applied simultaneously.

Types of Movements

• Translational (linear): body moves along a straight line (rectilinear) or a curved line (curvilinear).
• Angular (rotational): body rotates about an axis. Many living organisms use combined linear and angular movements for general motion (example: walking).
• Movements can occur linearly or rotationally.

Human Movement Mechanics

• Internal mechanics describe factors producing and controlling movement from within the body (example: muscle contractions, ligaments).
• External mechanics detail factors producing and controlling movement from outside the body (example: gravity, trauma).
• Descriptions and identifications of the factors involved in producing and controlling movement are valuable in evaluating and treating injuries.

Kinematics and Kinetics

• Kinematics describes movement without considering the forces causing it.
• It analyzes time, displacement, velocity, and acceleration
• Kinetics studies the forces producing or changing motion and analyze various force categories (linear and angular motion).

Statics and Dynamics

• Statics analyses balanced forces where the body is in equilibrium (motion or motionless).
• Dynamics studies unbalanced forces causing changes in velocity or direction.
• Work, energy and acceleration are considered in dynamic analyses.

Assessing Kinematics

• Qualitative assessments use observation ('good' or 'bad').
• Quantitative assessments leverage numerical data ("numbers") to improve accuracy and objectivity (examples: time, displacement, velocity, acceleration).
• Temporal characteristics: analyzing the duration and rate of movement, including instances of acceleration and deceleration.
• Spatial characteristics describe movement direction, distance, location, magnitude (describing the occurrence and changes in segment displacement), velocity (how fast it moved), and acceleration (how quickly velocity altered).

Quantities in Mechanics

• Vector quantities possess magnitude and direction (example: force).
• Scalar quantities possess only magnitude (example: distance, mass).

Time-Based Kinematic Data

• Temporal characteristics of kinematics (time): measure duration of events (e.g., time in air during jump), durations of specific actions (e.g., right foot contact with the ground), and rate of force application during injuries.

Spatial Kinematic Data

• Describe displacement types (linear/translational, angular/rotational, or combined).
• Analyses can involve rectilinear (straight line) or curvilinear (curved line) motion.
• Human body segment motion involves both translation (linear motion) and rotation (angular motion).

Angular or Rotational Motion

• In angular or rotational motion, objects move along a circular path around an axis (also called axis of rotation).
• In true rotation, all points on the segment move through the same angle at the same time, and remain at a constant distance from the center of rotation.
• Human movement typically involves forces applied away from the axis of rotation and the resulting torque is associated with angular acceleration.

Kinematics: Spatial Displacement

• Describe position or location in space for complete movement description.
• Locations can be qualitative ("arm in abduction") or quantitative ("arm flexed at 45 degrees").
• The reference system used for locating body segments is important in injury analyses.

Coordinate Systems

• In 3D analyses, three axes (x, y, and z) or (X, Y, and Z) provide useful frames of reference.
• In human body analysis, axes commonly align with the coronal, vertical/longitudinal, and anteroposterior planes and corresponding x, y, and z-axes.
• Degrees of freedom (DOF) relate to the kinematic measurements needed to specify an object's position (for 2D motion of a segment, 2 DOF are necessary; 3 DOF for 3D).

The 3D Motion of a Body Segment

• 6 degrees of freedom (DOF) are associated with 3 translations and 3 rotations.
• Arthrokinematics refers to the small gliding or linear motions between joint surfaces.
• Osteokinematics represents the three anatomical rotations (flexion/extension, abduction/adduction, and internal/external rotation) in a body segment.

Relative Reference Systems

• All joints, excluding the ankle (90°) and forearm, are typically at 0°.
• Fundamental standing positioning versus anatomical standing positioning.

Standard Reference Terminology-Anatomical Reference Planes

• Cardinal planes include sagittal, frontal, and transverse.
• Sagittal: divides the body into left and right halves.
• Frontal: divides the body into anterior (front) and posterior (back) halves.
• Transverse/horizontal: divides the body into superior (upper) and inferior (lower) halves.

Standard Reference Terminology- Anatomical Reference Axes

• Imaginary axes of rotation through joints.
• Mediolateral: related to sagittal plane.
• Anterioposterior: related to frontal plane.
• Longitudinal: related to transverse plane.
• Three axes are associated with one specific plane (axis perpendicular to the plane).

Kinematic Quantities-Displacement

• Displacement—a vector- measures the change in position from a starting to an ending point irrespective to the path taken;
• Distance—a scalar- measures how far the body has moved irrespective to the path taken.

Kinematic Quantities-Velocity

• Velocity—a vector—measures the rate of displacement over time, including magnitude and direction.
• Examples: 5 m/s East, 5 deg/sec.
• Speed—a scalar—measures the rate of displacement, disregarding direction.
• Examples include: 5 m/s or 5 deg/sec.

Kinematic Quantities-Acceleration

• Acceleration—a vector—measures the time rate of change in velocity.
• Linear acceleration is the rate at which the velocity of a moving object is changing with time. It is expressed in units of m/sec².
• Earth's gravitational pull exerts an acceleration of 9.81 m/s².
• Angular acceleration measures the time rate of change in angular velocity, which is expressed in deg/sec².

Kinematic Analysis

• Five kinematic variables completely describe motion or displacement—type/kind of motion; location & direction displacement; magnitude of displacement ; rate of displacement OR rate of acceleration (velocity or acceleration).

Goniometry

• Goniometry is used to determine joint movement magnitude.

Motion Analysis Lab and Videography

• Employed for measuring displacement, velocity, and kinematic acceleration magnitudes and directions.

ROM Measurement Tools

• Used to determine range of motion (ROM) in various joints.
• Tools include goniometers, motion analysis labs, and videography approaches.

Videotape

• Used to study and analyze movement in various activities (e.g., running).

Isokinetic

• Isokinetic: Constant or uniform kinetic motion (movement).
• Isokinetic dynamometers are used to perform isokinetic exercise testing that maintains constant angular velocities throughout the movement range.
• It prevents angular acceleration from exceeding a pre-set speed.

Kinetics: Force

• Forces—pushes or pulls—cause motion or maintain rest in the body.
• Kinetics studies internal and external forces that cause or affect motion.
• This includes the relationship between a body's resistance to changing its linear or angular state of motion, and the effect of applied forces and torque.

Kinetics: Internal Forces

• Internal forces originate from the body itself (examples: muscle contraction, ligament pull on bones, bone-on-bone pressures at joints, and blood/fluid flow).

Kinetics: External Forces

• External forces originate outside the body (examples: gravity, wind, water, other objects).

Different Types of Forces

• Muscular force
• Gravitational force
• Friction force
• Contact forces (ground contact/collision forces)
• Inertia forces

Free-Body Diagram

• A graphic representation of all forces acting in a system for biomechanical analyses.
• Gravity is usually represented as a single vector.

Center of Mass (CoM)

• CoM is the single point that represents the entire body or body segment mass distribution for simplification.
• This point is crucial in analyzing the effects of gravity on the body and body segments.
• Center of mass and center of gravity are typically located in similar points.
• For symmetrical objects, the CoM is often found at the geometrical center.
• For asymmetrical objects, the CoM is usually located towards the heavier end.

Segmental Centers of Mass

• Multiple segments can be combined into a single one for simplified gravitational effects.
• The CoM position remains constant even when segments are rearranged.
• When two or more linked segments rearrange, the overall CoM will change.

Center of Mass and Posture Analysis Analysis

• The CoM lies approximately in front of the second sacral vertebra (S2).
• Analyzing posture involves observing the symmetry, alignment, and potential deviation from the appropriate posture through observation strategies using plumb lines and posture analysis systems.

Injury-Causing Situations

• Magnitude: the applied force's strength.
• Location: the spot on the body where the force is applied.
• Duration: the length of force application.
• Frequency: the number of times the force is applied.
• Variability: whether the applied force's magnitude is steady or fluctuating.
• Rate: the speed at which the force is applied (e.g., speed of impact).

Test your understanding of the key concepts in biomechanics with this engaging quiz. It covers fundamental terms, types of motion, and applications in various professions. Perfect for students studying kinesiology or physical therapy.