Biomechanics Angular Kinematics

Nearly all movement involves what?

rotation

What is angular kinematics?

temporal and spatial characteristics of angular motion

Based off of timing and ROM, what can we infer things about?

muscle actions and joint forces

What is angular motion?

when all parts of an object move through the same angle but do not undergo the same linear displacement

Translational motion of the body involves both linear and angular movements? T/F

true

What makes up an angle?

two segments that intersect at a vertex

What is digitizing?

converting movement into digital coordinates

What is a passive motion capture system?

a system using reflective markers to track movement

What is an active motion capture system?

a system where markers emit their own light to track movement

What are the pros of an inertial measurement unit?

minimal setup, low cost, and is portable

What are the cons of an inertial measurement unit?

no absolute positional data, errors from integrations, and difficult to line up with anatomy

What are the three common units of measurement in angular kinematics?

degrees, revolutions, and radians

What is a revolution?

360 degrees in a full circle

What is a radian?

57.3 degrees and typically measured in pi

What is a relative angle?

the angle between two adjacent segments

How is medical measurement of angles different?

it does not measure from an absolute horizontal point

What is angular distance?

a scalar measure for the total distance travelled

What is angular displacement?

a vector measure for the difference between the initial and final positions of a rotating object

Is clockwise movement positive or negative?

negative

What is an angle-time plot?

a graph used to visualize how angles change during a movement

An ankle joint with an angular velocity of −2.4 rad/s is plantarflexing T/F

true

During running, what sagittal plane actions at the hip, knee, and ankle occur at initial ground contact?

hip extension, knee flexion, and ankle dorsiflexion

What is the absolute angle of the trunk when standing upright?

90 degrees

Is the knee flexion angle greater at foot contact when running or walking?

running

Do relative angles provide information on orientation of the body or segments in space?

no

In quadrant one, the degrees are —

degrees

In quadrant II, the degrees are—

-degrees + 180

In quadrant III, the degrees are—

degrees + 180

In quadrant IV, the degrees are—

-degrees + 360

What does the law of cosines allow for?

to calculate segment angles not at right angles to each other