S2 Lecture 1 Flashcards
What are experimental methods of data collection and analysis?
- Motion analysis
- Force analysis
- Electromyography
- Imaging
What is the definition of kinematics?
The spatiotemporal characteristics of movement
How can we quantify linear or angular displacement?
- Measure it
- Through the differentiation of joint coordinate data
- Defining the spatial coordinates of the participant, or certain landmarks on their body, and tracking their change during motion.
How are joint angles also known as?
“Relative” angles
What is the main advantage of using a mechanical goniometer to measure joint angles?
We can measure the joint angle directly
What are the two methods of analysis in biomechanics?
Theoretical (semsester 1) and experimental (semester 2)
How do we acquire linear kinematic data?
Displacement: Tape measure, GPS, Digitised coordinates from motion analysis.
Velocity: Speedometer, GPS, Radar gun (tennis), Hawkeye (tennis), Differentiate displacement data
Calculation for average velocity:
(Start displacement - Final displacement) / (Final time-Start time) = ds/dt = (Si+1 - Si) / (Ti+1 - Ti)
Calculation for average velocity using central differences:
ds/2dt= (Si+1 - Si-1) / (Ti+1 - Ti-1)
Instantaneous velocity from digitised displacement data
Vinst=ds/dt~change in s/change in t=Vavg for change in t->0
Angular velocity:
change in angle/change in time
Angular acceleration:
change in velocity/change in time
What are the two main methods for calculating angular kinematics:
- Calculating angles from digitised body landmarks, i.e. from 2D coordinate data
- Goniometry
What is the absolute angle?
Angle measured from the horizontal
What is the relative angle?
Angle of one segment relative to the segment beside it
What is the cosine rule?
a^2=b^2+c^2-2bc*cos(A)
What is goniometry?
-Measures the joint angles
-Mechanical goniometers: direct measurement of angle, only under isometric conditions
-Electrical goniometers: need to calibrate to convert voltages into degrees, typical sampling frequency ~1000Hz
