EMG

Question 1

GRF at initial contact

Answer 1

Ankle DF
Knee Ext
Hip Flex

Question 2

Muscles activated at initial contact

Answer 2

TA - ecc
Hamstrings - help to start knee flex (conc)
Quads - stabilize the knee (ecc)
Extensors (glut max) - conc to overcome flexion torque

Question 3

Initial contact

Answer 3

0/1% (an instant, not a phase)

Question 4

GRF Loading response

Answer 4

Ankle PF
Knee Flex
Hip Flex

Question 5

Muscles activated at loading response

Answer 5

TA (ecc)
Quads (ecc) - going into knee flexion
Hams (conc) - help flex the knee
Extensors (glut max) - conc to extend the hip

Question 6

Loading response is what percent of gait cycle

Answer 6

0-10%

IC to Opp TO

Question 7

Opposite Toe off GRF

Answer 7

Ankle PF
Knee Flex
Hip Flex

Question 8

Muscles activated at opposite toe off

Answer 8

TA (ecc)
Quads (ecc) knee flexion to load weight
Hams (conc) flexing the knee
Hip ext glut max (conc)

Question 9

When is opposite toe off

Answer 9

10% at the end of loading response and the beginning of midstance
It is an instant, not a phase

Question 10

GRF at midstance

Answer 10

Ankle DF, Knee Flex, Hip Ext

Question 11

Midstance - EMG

Answer 11

Triceps Surae (ecc) to control the tibia
Quads (conc) is fading out because knee is starting to extend
Glut max (conc) also fading out because noe GRF is producing hip ext

Question 12

When is midstance

Answer 12

10-30% of the gait cycle

Opp Toe Off to Heel Off

Question 13

Terminal Stance GRF

Answer 13

Ankle DF, Knee Ext, Hip Ext

Question 14

Terminal Stance muscle activation

Answer 14

Triceps surae (Ecc and then conc when contributing to PF for push off)
Quads - Ecc to control knee flexion
Quads - conc to help with hip flexion
Iliopsoas - Fires at the end to stop hip ext (ecc) and then is conc to start hip flex

Question 15

When is terminal stance

Answer 15

30-50%

Heel off to Opp IC

Question 16

Toe Off GRF

Answer 16

Ankle DF, Knee Flex, Hip Ext

Question 17

Toe Off Muscle activation

Answer 17

TA (conc) to stop PF and DF the foot
Quads (RF - Ecc) to control knee flexion so we dont kick butt
Iliopsoas - conc to produce hip flexion for swing

Question 18

When is Toe off

Answer 18

An instant, not a phase

At the end of Terminal Stance - 50%

Question 19

Feet Adjacent GRF

Answer 19

No GRF from the body - just gravity which is related to the weight of the leg

Question 20

Feet Adjacent muscle activation

Answer 20

TA (isometric) to control the ankle

Iliopsoas conc for hip flex

Question 21

When is feet adjacent?

Answer 21

73% - an instant, not a phase

At the end of initial swing

Question 22

Tibia vertical GRF

Answer 22

No GRF from the body - just gravity which is related to the weight of the leg

Question 23

Tibia Vertical Muscle Activation

Answer 23

TA (isometric) to control the foot so the heel will contact ground
Hamstrings (ecc) to stop flexion at hip (conc) to start flexing the knee

Question 24

When is tibia vertical

Answer 24

87% - an instant, not a phase

At the end of midswing

Question 25

Rockers and Powers

Answer 25

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