Muscle Activation during Gait

Question 1

what produces an external torque during gait?

Answer 1

GRF

will cause movement at each joint of the LE

Question 2

what produces an internal torque during gait?

Answer 2

primarily muscle activation

it is produced to match/overcome the external torque

Question 3

when and why do concentric muscle contractions occur during gait?

Answer 3

they occur when the internal torque is moving the joint in the direction of the muscle’s activity

these provide stability and produce movement of a segment

Question 4

when and why do eccentric muscle contractions occur during gait?

Answer 4

they occur when an internal torque is moving the joint in the direction opposite of the muscle’s action

these help with shock absorption and deceleration of a limb segment

Question 5

what can cause muscular dysfunction and how will it impact gait?

Answer 5

Causes:

1. weakness
2. loss of power
3. decreased endurance
4. spasticity
5. contracture

leads to altered gait patterns and compensations as the torque GRFV doesn’t change but the individual’s ability to counter it does

Question 6

what muscles are activated at the hip in the sagittal plane during IC?

Answer 6

ALL hip extensors contract concentrically to prepare for LR

Question 7

what muscles are activated at the knee in the sagittal plane during IC?

Answer 7

eccentric hamstring contraction to counteract extension torque

knee extensions transition from concentric to eccentric contraction in preparation for LR

Question 8

what muscles are activated at the ankle in the sagittal plane during IC?

Answer 8

pretibials (tibialis anterior, big toe extensors) contract concentrically

Question 9

what muscles are activated at the hip in the sagittal plane during LR?

Answer 9

concentric contraction of hip extensors

(Glute max, adductor magnus, TFL, Glute med peak)

Question 10

what muscles are activated at the knee in the sagittal plane during LR?

Answer 10

eccentric contraction of knee extensors

(quad activity peaks)

Question 11

what muscles are activated at the ankle in the sagittal plane during LR?

Answer 11

eccentric contraction of ankle DF (tibialis anterior peaks)

Transition to eccentric contraction of ankle PF in late LR

Question 12

what muscles are activated at the hip in the sagittal plane during MSt?

Answer 12

no hip muscular activity requried in the sagittal plane

Question 13

what muscles are activated at the knee in the sagittal plane during MSt?

Answer 13

quads eccentric to no activity

Question 14

what muscles are activated at the ankle in the sagittal plane during MSt?

Answer 14

eccentric contraction of the gastroc/soleus

Question 15

what muscles are activated at the hip in the sagittal plane during TSt?

Answer 15

minimal activity in the sagittal plane

Question 16

what muscles are activated at the knee in the sagittal plane during TSt?

Answer 16

no quad or HS activity

tibial position maintained by gastroc

Question 17

what muscles are activated at the ankle in the sagittal plane during TSt?

Answer 17

concentric contraction of ankle PF to prevent tibial collapse with heel rise

Gastroc/Soleus activity peaks

Question 18

what muscles are activated at the hip in the sagittal plane during PSw?

Answer 18

concentric contraction of hip flexors

adductor longus peaks

Question 19

what muscles are activated at the knee in the sagittal plane during PSw?

Answer 19

knee flexion is mainly passive

slight concentric contraction of knee flexors and eccentric rectus

Question 20

what muscles are activated at the ankle in the sagittal plane during PSw?

Answer 20

ankle PF activity ceases in early PSw and passive tension contributes to ankle moving in PF

ankle DF concentric initiated at the end of PSw

Question 21

what muscles are activated at the hip in the sagittal plane during ISw?

Answer 21

continued concentric contraction of hip flexors

Iliacus peaks

Question 22

what muscles are activated at the knee in the sagittal plane during ISw?

Answer 22

concentric contraction of knee flexors

(biceps femoris SH, sartorius, gracilis peak)

flexion continues to be aided by flexion at the hip

Question 23

what muscles are activated at the ankle in the sagittal plane during ISw?

Answer 23

concentric contraction of tibialis anterior

toe extensor activity peaks

Question 24

what muscles are activated at the hip in the sagittal plane during MSw?

Answer 24

continued concentric contraction of hip flexors

initation of eccentric hip extensors (HS) to control hip flexors

Question 25

what muscles are activated at the knee in the sagittal plane during MSw?

Answer 25

knee extension created by momentum knee flexors contract **eccentrically** at the end of MSw to control extension

Question 26

what muscles are activated at the ankle in the sagittal plane during MSw?

Answer 26

continued **concentric** contraction of DF

Question 27

what muscles are activated at the hip in the sagittal plane during TSw?

Answer 27

**concentric** contraction of hip extensors

Question 28

what muscles are activated at the knee in the sagittal plane during TSw?

Answer 28

**concentric** contraction of knee extensors to insure full extension peak hamstring **eccentric** contraction to decelerate thigh

Question 29

what muscles are activated at the ankle in the sagittal plane during TSw?

Answer 29

continued **concentric** contraction of DF

Question 30

Describe the relative joint position and muscle activity at the hip in the sagittal plane during gait

Answer 30

use the chart

Question 31

describe the relative joint position and muscle activity at the knee in the sagittal plane during gait

Answer 31

use the chart

Question 32

describe the relative joint position and muscle activity at the ankle in the sagittal plane during gait

Answer 32

use the chart

Question 33

what muscles are activated at the hip in the frontal plane during LR and MSt?

Answer 33

1. LR → hip abductors contracting **eccentrically** * Glute med and adductor magnus at peak 2. MSt → hip abductors contracting **eccentrically** then **concentrically**

Question 34

what muscles are activated at the ankle in the frontal plane during LR and MSt?

Answer 34

invertors contracting **eccentrically** during both phases

Question 35

what muscles are activated at the hip in the frontal plane during TSt and PSw?

Answer 35

hip abductors contracting **concentrically**

Question 36

what muscles are activated at the ankle in the frontal plane during TSt and PSw?

Answer 36

invertors contracting **concentrically**

Question 37

what muscles are activated at the hip in the frontal plane during the entire swing phase?

Answer 37

hip adductors contract **concentrically**

Question 38

what muscles are activated at the ankle in the frontal plane during the entire swing phase?

Answer 38

evertors contract **concentrically**

Question 39

describe the relative joint position and muscle activity at the hip in the frontal plane during all of gait

Answer 39

use the diagram

Question 40

describe the relative joint position and muscle activity at the ankle in the frontal plane during all of gait?

Answer 40

use the diagram below

Question 41

what are the key roles of the ankle dorsiflexors during gait?

Answer 41

eccentric activation to **control plantarflexion** of the ankle at IC until foot flat

Question 42

what are the key roles of the ankle plantarflexors during gait?

Answer 42

1. **eccentric** contraction moving into MSt to **control tibial advancement** 2. **concentric** contractions at TSt assists with forward propulsion

Question 43

what are the key roles of the ankle invertors during gait?

Answer 43

1. **eccentrically** contracts to **control pronation** until MSt 2. **concentrically** **contracts to supinate** the foot for **push off** in TSt/PSw

Question 44

what are the key roles of the ankle evertors during gait?

Answer 44

also active as co-contraction to counter strong inversion effect occuring during LR/MSt

Question 45

what are the key roles of the knee extensors during gait?

Answer 45

1. **eccentrically** **control knee flexion** in LR 2. **Concentrically to extend the knee** and support the body in MSt

Question 46

what are the key roles of the knee flexors during gait?

Answer 46

**Decelerate knee extensors** in preparation for placement of the foot on the ground

Question 47

what are the key roles for the hip extensors during gait?

Answer 47

activated in TSw prior to IC to **initiate hip extension** and **prepare LE for weight acceptance** at the beginning of stance

Question 48

what are the key roles for the hip flexors during gait?

Answer 48

**advance LE** forward during ISw Concentrically **lift LE** to allow for toe clearance during swing

Question 49

what are the roles of the hip abductors during gait?

Answer 49

**Control the slight lowering** of the contralateral pelvis on the side of the swing limb then provide pelvic stability in stance

Question 50

what are the key roles of the hip adductors during gait?

Answer 50

**assist** with the initation of **hip flexion** after toe off

Question 51

List some gait deviations

Answer 51

1. Trendelenburg gait 2. compensated trendelenburg gait 3. foot slap 4. knee extension thrust

Question 52

what phase of gait is Trendelenburg gait observed?

Answer 52

LR → PSw | (observed best in frontal plane)

Question 53

what does Trendelenburg gait look like?

Answer 53

excessive downward drop of the contralateral pelvis during stance

Question 54

what is the cause of both Trendelenburg and compensated Trendelenburg gait?

Answer 54

glute medius weakness

Question 55

what is the result of Trendelenburg gait?

Answer 55

a functionally longer swing limb resulting in decreased efficiency and possibly decreased stance time

Question 56

what differentiates Trendelenburg from compensated Trendelenburg gait?

Answer 56

compensated Trendelenburg gait utilizes a trunk lean over the stance leg to try and maintain a level pelvis

Question 57

what does a foot slap gait look like? what phase of gait is it most noticed and in what plane?

Answer 57

PF torque goes unchecked by anterior tib occurs during IC → LR best observed in the sagittal plane

Question 58

what are some potential causes of a foot slap gait?

Answer 58

tib anterior weakness (from a peroneal nerve palsy or peripheral neuropathy)

Question 59

what is the result/impact of "foot slap" on gait?

Answer 59

rapid PF after heel contact which can be audible usually can clear foot during swing

Question 60

what does a knee extension thrust during gait look like? what phases does it typically occur in and what plane is the best to view it?

Answer 60

knee snapping back into extension early in stance phase phase → IC plane → sagittal

Question 61

what are some potential causes of a knee extension thrust gait deviation?

Answer 61

quad spasiticy from UMN lesion

Question 62

what is the result/impact of a knee extension thrust gait deviation?

Answer 62

rapid and often excessive knee extension during LR, can occur w/cause knee hyperextension over time