Lecture 1 Flashcards
What is kinematics?
Study of motion without regard to forces causing the motion.
What are the components of movement?
Translation + rotation.
What are the key variables in kinematics?
Position, Displacement, Velocity, Acceleration.
What is a global coordinate system?
Fixed to a point in space, 3D.
What is a local/anatomic coordinate system?
Fixed to a rigid body, 2 local coordinates compared to determine joint angle.
How many degrees of freedom are in a 3D system?
6 degrees of freedom (3 translation, 3 rotation).
What is kinetics?
Study of motion under forces.
What is moment/torque?
Acceleration x force, force distant to a centre of rotation.
What are the key concepts in kinetics?
Work, Power, Energy.
What is Newton’s 1st Law?
Object at rest remains at rest or continues moving at constant velocity unless acted upon by an unbalanced external force.
What does the sum of forces and moments equal in Newton’s 1st Law?
Sum of F = 0, Sum of M = 0.
What is Newton’s 2nd Law?
Unbalanced force acting on an object produces acceleration in the direction of the force.
What is the formula for Newton’s 2nd Law?
F = ma.
What is Newton’s 3rd Law?
For every action there is a reaction equal in magnitude but in the opposite direction.
What is anthropometry?
Study of physical measurement of the human body.
What does anthropometry measure?
Segment length, segment mass, centre of mass location, radius of gyration.
What is the centre of mass?
Point on which any line passing through it divides the body in half.
How is the centre of mass characterized?
Mass equally distributed, changes with movement, can be found for segments or whole body.
What is Kinematics?
Kinematics is the study of motion, including the measurement of position, velocity, acceleration, and joint angles.
What are motion capture systems used for?
Motion capture systems measure position, velocity, acceleration, and joint angles.
What are the types of motion capture systems?
- Camera
- Optoelectric, electromagnetic, and ultrasound
- Inertial sensors
- Markerless systems
How do optoelectric systems work?
Optoelectric systems use markers that emit (active) or reflect (passive) infrared light, which cameras then identify for position measurement.
What are the advantages of optoelectric systems?
Advantages include high accuracy, the ability to be wireless, and not being influenced by metals.
What are the disadvantages of optoelectric systems?
Disadvantages include the potential for markers to be occluded and post-processing time with some systems.
How do electromagnetic systems operate?
Electromagnetic systems use receivers (markers) that pick up a magnetic field emitted by a transmitter.
What are the advantages of electromagnetic systems?
Clear line of sight is not necessary.
What are the disadvantages of electromagnetic systems?
Disadvantages include metal interference, limited range, and the need for wires.
What is an electrogoniometer?
An electrogoniometer measures joint angles during movement by detecting changes in electrical current when the device is bent.
What are the advantages and disadvantages of electrogoniometers?
Advantages: cheap, simple.
Disadvantages: difficult to align, movement can be limited by the device.
What do accelerometers measure?
Accelerometers measure acceleration and can determine net force, velocity, or displacement, and monitor physical activity.
What are force transducers?
Force transducers are devices that measure strength (F) and can be isokinetic, hand-held, or used for grip strength.
What is electromyography?
Electromyography measures muscle activation during different activities using indwelling or surface electrodes.
What do pressure sensors measure?
Pressure sensors measure plantar pressure and utilize different technologies, including piezoelectric.
