Week 11 Flashcards
What can be measured cheaply in field
2D motion capture
What is expensive to do in field
3D motion capture
Force plates
Electromyography
Dynamometry
What are some wearable sensors
Skin patches Smart watches Headbands Mobile and tablet applications Giomechanical shoe insoles Smart garments Inertial measure unit
Wearable sensors can be worn
They often have
Compatible with
During normal activities
Dataloggers - store data within the device
Smart phone apps, computer programs for viewing and data analysis
Wearable sensors usually are
Electromyography
Acceleratometers
IMU sensors
What is an accelerometer
Measures linear accelerations in 1 to 3 planes of motion
In lab how many planes do our accelerometers measure
3 planes
What is a gyroscope
Measures angular acceleration in 1-3 planes of motion
What is a magnetometer
Measures magnetic fields and can be used to measure orientation relative to the earths magnetic field
IMU are
Inertial measurement unit
A combination of an accelerometer and gyroscope, sometimes magnetometer
Allows you to measure both linear and angular accelerations, as well as orientation
Smart phones contain
All 3 measurements devices
Plus GPS
These sensors are accessed and utilised by a variety of apps
On a accelerometer, what is vertical, anterior posterior and medial lateral
X = vertical
Y = anterior posterior
Z = medial/lateral
Accelerometer can detect
Gravity
Accelerometer measures in what unit
1 g = 9.8 m/s^2
What is peak positive acceleration (PPA)
Can measure what if placed at bottom of tibia
How is this related to risk of injury
Peak vertical acceleration in the positive direction during running or other task
Measurement of tibial shock if placed directly above ankle
Higher numbers mean more force at the tibia, increasing risk of injury
Each peak on a accelerometer graph is a
PPA
Gait retraining research shows that
PPA of the tibia, vertical force impact peak and average and instananeous vertical force loading rates were all reduced immediately
Decrease in 50% tibial acceleration
Vertical force impact peak decreased by 20%
Vertical force loading rates decreased by 30%
How did they reduce the factors in gait retraining research
Increasing cadence
Landing softer
Overall what different things can accelerometers be used to measure
Tibial shock
Running or cycling cadence
Retraining poor biomechanics
Quantifying balance deficits after injury
All can be done cheaply and remotely
Measures absolute orientation relative to the Earth’s magnetic field
Magnetometer
Combines information from 2 or 3 of the other tools into 1 piece of equipment
Inertial measurement unit
Measures linear accelerations in 1-3 planes
Accelerometer
Measures angular accelerations in 1-3 planes
Gyroscope
Motion capture systems cannot be brought outside to perform 3D motion analysis
False
Any new smartphone will contain an accelerometer, gyroscope, and magnetometer
True
Assuming the following definitions
X = vertical
Y = anterior/posterior
Z = medial/lateral
And, that the accelerometer is positioned perfectly vertical, what measurements should be recorded in the x-direction
1 g
Which of the following data can you not obtain with an accelerometer
Peak angular acceleration of the segment the accelerometer is placed on
We would expect to find higher medial / lateral acceleration of the trunk after a participant has suffered a concussion
True
What does it mean that a wearable device has a datalogger function
Data is stored in the device, even when not in wireless range of your computer
