Angular Kimematics - Joint Angles In Running

Question 1

5 assumptions when digitising

Answer 1

Skin markers represent underlying bone and joint movements ( could surgically insert markers but is invasive)
Skin movement is 0
No ‘wobbly’ mass
Segments of body are Rigid and are represented by straight lines joining skin markers
2D joint rotations only ( in a Sagittal plane)

Question 2

5 positions of markers when analysing joint angles in running

Answer 2

HIP 1cm posteriorly
KNEE 1cm anteriorly (lateral epicondyle)
ANKLE on the bone
MTP base of big toe
HEEL calcaneus

Question 3

In degrees, what is absolute zero?

What does it look like?

Answer 3

180 degrees

Completely straight leg

Question 4

Phases of ground contact in knee (in order)

Answer 4

Foot strike
Initial support
Mid stance
Toe off

Question 5

Describe foot strike of knee (flex, ext, angle value)

Answer 5

10 degrees flexion

Question 6

Describe initial support of knee

Answer 6

Cushioning flexion

Reduces shock wave

Question 7

Describe mid stance of knee (flex, ext, angle value)

Answer 7

Peak/max flexion

38 degrees

Question 8

Describe toe off in knee (flex, ext, angle value)

Answer 8

13 degrees extension

Question 9

Phases of ground contact in ankle (in order)

Answer 9

Foot strike
Initial support
Mid stance
Toe off

Question 10

Describe foot strike in ankle (flex, ext, angle value)

Answer 10

90 degrees flexion

Question 11

Describe initial support in ankle

Answer 11

Small amount of plantar flexion

Question 12

Describe mid stance in ankle (flex, ext, angle value)

Answer 12

108 degrees dorsal flexion

Question 13

Describe toe off in ankle

Answer 13

Plantar flexion

Question 14

Swing phase

Answer 14

Flexion following the extension to get the next step

Max amount of flexion as leg is pulled up into next step

Question 15

Draw knee angle time history

Answer 15

X axis = time (m/s) 0 to 60
Y axis = knee angle (degrees) 0 to 200
Max angle = max knee flexion (when the angular convention is in front of the knee)
Curve = 10 degrees until 40, up to 50 degrees at 100, down to 200

Question 16

Draw ankle angle time history

Answer 16

X axis = ankle angle (degrees) 0 - 130
Y axis = time (m/s) 0 - 100
Max angle = maximum ankle flexion. (When angle convention is underneath the foot)
Curve = 105 degrees at 5, 95 degrees at 25, up to 115 at 50, flat to 100, down to 200

Question 17

What to consider when drawing knee/ankle time histories

Answer 17

If convention is in front of knee, regular time history
If convention is behind knee, flip time history upside down

If convention is below foot, regular time history
If convention is above foot, flip time history upside down

Question 18

Why might Line in time history be bumpy?

Answer 18

When data is raw or unfiltered.
This means it isn’t standardised relative to the standing position
(subject may be standing straight with 10 degrees knee flexion)

Question 19

Angular velocity of thigh time history

Answer 19

X axis - time
Y axis - degrees
Horizontal line with shallow dip in middle of time. Line rises back up to just below original position

Question 20

Angular acceleration time history for thigh

Answer 20

X axis time
Y axis degrees
Angle dips to start and then rises gradually to a plateau higher than initial position

Question 21

In angular acceleration time history, what does the polarity of acceleration show?

Answer 21

Polarity (-ve / +ve) shows the rate at which the angle is changing
NOT showing the angle itself getting bigger or smaller

Question 22

Peak ankle Dorsi-flexion velocity?

Answer 22

6.5 rad per sec

Question 23

Peak knee flexion velocity?

Answer 23

9.5 rad/s

Question 24

Sagittal plane angles in sprinting:

Is it viable to test sprint running on treadmills?

Answer 24

Not for the start of the sprint but as the study goes on, peak values start to coincide with expected results
Also not at the end when person slows down

Question 25

Uphill running and its effects on claves?

Answer 25

An increase in Doris flexion =
Reduction in initial knee extension & Reduction in knee flexion velocity =
Tight calves

Question 26

Achilles’ tendon study author and year

Answer 26

Dixon and Kerwin

1999

Question 27

Achilles’ tendon study aims (X2)

Answer 27

Influence of heel lift manipulation on Sagittal plane kinematics in running
Ways to reduce strain using inserts in shoes

Question 28

Achilles’ tendon study results

Answer 28

Inserts shortened the length and stretch of Achilles’ tendon due to reduction in dorsi-flexion

NO CHANGE in knee angle
REDUCTION in ankle dorsi-flexion

Question 29

Literature comparisons of changes in angles during running gait cycle : considerations of different results from different authors?

Answer 29

Comparison of results is influenced by:
Variability between subjects
Differences in marker placements
Different angular conventions

Question 30

Description of joint angle changes in the THIGH during running

Answer 30

Foot strike - angle positive indicating hip flexion
Initial support - little change in angle of hip/thigh
Mid stance - angle negative indicating hip extension
Toe off - max extension of thigh
Swing phase - thigh is flexed

Question 31

Description of KNEE joint angle changes during running

Answer 31

Foot strike - flexion
Initial support - flexion to cushion ground impact
Mid stance - begins to extend
Toe off - continued extension
Swing phase - initially flexed then extended

Question 32

Description of ANKLE joint angle changes during running

Answer 32

Foot strike - angle at 90 degrees
Initial support - small amount of plantar flexion
Mid stance - Dorsi flexion peak
Toe off - plantar flexion
Swing phase - plantar flexion through to dorsi flexion

Question 33

Name 1 thing that influences the size of the angle

Answer 33

Angular conventions