Normal Gait Muscle Activation

Question 1

What are the ankle kinetics in IC/heel strike?

Answer 1

DF are active

Question 2

What are the knee kinetics in IC/heel strike?

Answer 2

Quads & hamstrings still active from Tsw; Quads eccentric; TFL contract to counteract internal rotation of the tibia and adduction (varus) torque (eccentric, TFL slows it down)

Question 3

What are the ankle kinetics at LR/foot flat?

Answer 3

Dorsiflexors eccentrically

Stops foot slap

Question 4

What are the knee kinetics at LR/foot flat?

Answer 4

Quads & hamstrings still active from Tsw; Quads eccentric; TFL contract to counteract internal rotation of the tibia and adduction (varus) torque (eccentric, TFL slows it down)

Question 5

What are the hip kinetics at LR/foot flat?

Answer 5

Hip extensors are all active (3 hamstrings, adductor magnus and gluteus maximus

Gluteus medius fires when unsupported side of pelvis drops

Internal rotation is decelerated by the gluteus maximus

Question 6

What are the ankle kinetics at Midstance?

Answer 6

Plantar flexors minimally 25% MMT eccentrically

Control tibia from ant translation over foot

Question 7

What are the knee kinetics at Midstance?

Answer 7

Quads active till Body Vector moves anteriorly; IT band provides lateral stability (concentric); Soleus lightens the load on quads by restraining the tibia (prevents anterior translation of tibia, allows for better knee extension)

Question 8

What are the hip kinetics at mid stance?

Answer 8

Body vector moves posteriorly; Gluteus medius still working; TFL helps

Question 9

What are the ankle kinetics at terminal stance/heel off?

Answer 9

Plantar flexors to 80% MMT-switch to concentric

Far away from BOS

Question 10

What are the knee kinetics at terminal stance/heel off?

Answer 10

3 extensor forces on the knee:
• Strong soleus activity
• BV anterior
• IT band
• Counteracting these forces are the popliteus and gastroc
• Unlocks the knee. Start to use hamstrings then

End of Tst: knee starts to flex
• Tibial stability is lost
Gastroc and popliteus keep firing

Question 11

What are the hip kinetics at terminal stance/heel off?

Answer 11

TFL continues to supply abductor force

Question 12

What are the ankle kinetics at preswing/toe off?

Answer 12

Decrease in plantar flexors

Question 13

What are the knee kinetics at pre swing/toe off?

Answer 13

No more foot stability and knee rolls forward

Gastroc and popliteus still active

Rectus femoris (active for hip flexion keep the knee from flexing too far)

Question 14

What are the hip kinetics are pre swing/toe off?

Answer 14

Rectus femoris activates

Question 15

What are the ankle kinetics at initial swing/acceleration?

Answer 15

Dorsiflexors to 25 % MMT

Question 16

What are the knee kinetics at initial swing/acceleration?

Answer 16

Knee flexes further from rapid hip flexion momentum

Short head of the biceps femoris causes further knee flexion

Sartorious and gracilus help knee flexion

Checked by Rectus femoris

Question 17

What are the hip kinetics at initial swing//acceleration?

Answer 17

Momentum & gracilis, sartorius

Question 18

What are the ankle kinetics at mid swing?

Answer 18

Dorsiflexors to 40% concentric and then isometric

Question 19

What are the knee kinetics at mid swing?

Answer 19

Passive extension

Question 20

What are the ankle kinetics at terminal swing/deacceleration?

Answer 20

Dorsiflexors still firing

Question 21

What are the knee kinetics at terminal swing/de acceleration?

Answer 21

Quads activate to lift tibia and foot

Hamstrings active to decelerate and prevent excessive knee extension

Question 22

what are the hip kinetics at terminal swing/de acceleration?

Answer 22

Hamstrings to stop leg; gluteus maximus and adductor magnus also fire; Gluteus medius at the end of the phase