Anatomy and Kinematics Flashcards
(20 cards)
Lateral
Away from midline
Medial
Toward midline
Proximal
situated nearer to the centre of the body or the point of attachment.
Distal
situated away from the centre of the body or from the point of attachment.
Flexion
sagittal plane - decreasing angle between two body parts
Extension
sagittal plane - increasing angle between two body parts
what is rotation?
movement left and right in the transverse plane
What are abduction and adduction?
movement away and toward the body midline in the frontal plane
Two examples of methods of direct measurement.
Electrogoniometer
Accelerometer
Pros and cons of direct measurement methods.
Pros: - electrogoniometer is inexpensive - output signal available instantly Cons: - accelerometer costly - can incumber movement - can restrict movement - relative angular data not absolute - can be sensitive to shorts - may give rise to noise artefacts
In direct measurement methods, why is noise so bad?
Because when moving between acceleration - velocity - position, the error term is amplified.
What is a method of indirect measurement. List its pros and cons.
Motion Capture Pros: - all data in Global Ref System - no limit on number of markers - little encumbrance to motion - video can be replayed Cons: - expensive - large turnaround - wired markers can incumber movement - some cant be used in daylight
In how many harmonics are 99% of power found when using markers?
Winter found them to be int he first 7 harmonics (<6Hz)
How can velocities be calculated with marker positional data?
Using the finite difference (central) method. For linear vel.
What is the Hallux?
the big toe
Basic description of accelerometer
Device that can be attached DIRECTLY to the body to measure LINEAR ACCELERATION in ONE OR MORE AXES. Basic function is to measure the REACTION FORCES via a FORCE TRANSDUCER. Measured using Newtons Second Law.
Advantages and disadvantages of accelerometer
A: output signal available immediately
D: costs if a lot required/ acc. relative to position on limb/ large number can encumber movement/ mass may give rise to artefacts, especially in rapid movements
For a displacement signal that is the sum of harmonics, why is it important to filter high frequency noise before determining velocities and accelerations?
The amplitude of the noise grows with differentiation (as a square for acceleration), therefore crucial to remove.
What is an isometric contraction?
A contraction in which the muscle length stays constant.
What are the three terms for Total Mechanical Energy of a segment. E =
mgy + 1/2mv^2 + 1/2Iω^2
