BIOMECH angular kinematics

angular (axial) motion

• spatially unchanging axis of rotation

• fixed/spatially doesn’t move, while other points move around it.

which of these is angular and linear? roll, spin, glide

• roll and spin=angular

• glide=linear

1 revolution is how much?

1 full circle (360 degrees)=2pie radians

pie=

3.1415927

radians to degrees and vice versa

rad to degrees (multiply)

degrees to radians (divide)

1radian=57.3 degrees

what is one radian?

• the two sides become one radian

• example: 1.25 revs=450degrees/57.3=7.85rad

angular distance

actual traveled angular path

angular displcement

change in angular position (only care for beginning and end)

angular speed

angular distance/time

angular velocity

angular displacement/time

angular acceleration

change in angular velocity/time

counterclockwise vs clockwise pos or neg

counter=pos

clock=neg

relationship between linear and angular velocity

v=rw

w=change in angular velocity

direction is tangent to the arc. angular velocity must be expressed in rad/s)

example: tall and long arm verses short and strong have high..

tall/long=high radius

short/strong=w

carrying angle

lateral deviation of forearm to upperarm

angle of inclination

trunk and knee?

genu varum and genu valgum

varum=feet inward and knees out

valgum=feet out, knees in

Q-angle

• direction of pull to determine by that angle

• line of pull of quads

• (head of femur to patella)

more heel strike means more what?

braking force

what is the support phase include

heel-strike, mid-support, toe off

(braking and accelerating phase)

what does the braking phase include

heel-strike and mid-support

what does the accelerating phase include

mid-support and toe off

what is the flight phase

the leg coming around

in the air

single support is when

one foot on the ground/contact

double support is

both feet on ground/contact

is walking and running double or single support?

walking=double

running=single

stride length=

stride length=d(takeoff)+d(flight)+d(landing)

stride length is one step length

stride time=

stride time=(support time +flight time)/2

stride frequency

stride frequency=1/stride time

how many strides in 1 second

speed=

stride length(SL)*stride frrequncy(SF)