Gait Flashcards
1
Q
ANKLE - loading response
A
- Normal: resisted by a DF moment produced by TA, which contracts eccentrically, absorbing power (A1) + permitting the foot to be lowered gently to the ground
2
Q
ANKLE - mid-stance
A
- Increasing PF moment throughout mid-stance + into terminal stance, as the GRF vector moves into the forefoot. This moment is generated by the triceps surae, contracting eccentrically + absorbing power (A1)
- Ankle moment during stance phase: get a small DF at the beginning in the loading response + then the rest of the stance phase all have a PF moment + there will be parts that are eccentric or concentric
3
Q
ANKLE - terminal stance
A
- Increasing plantarflexion moment as first the soleus + then both soleus + gastrocnemius together (triceps surae) contract increasingly strongly. The contraction is initially eccentric, w/ power absorption (A1)
- GRF vector is in front of the joint at opposite initial contact resulting high PF moment by a concentric contraction of the triceps surae + large generation of power (A2) to accelerate the limb forward into the swing phase
4
Q
ANKLE - pre-swing
A
- PF moment reduces rapidly during pre-swing as the magnitude of the GRF declines, falling to zero as the foot leaves the ground as toe off
- Ankle power gen peak also declines to around zero = as foot is starting to leave the ground
5
Q
ANKLE - swing to initial swing
A
- Rapidly DF to allow foot clearance from ground
- TA contract concentrically to DF the ankle joint
6
Q
ANKLE - mid to terminal swing
A
- TA continues to contract concentrically to DF ankle for toe clearance
7
Q
KNEE - loading response
A
- Knee flexor moment due to contraction of the hamstrings as they prevent hyperextension at the end of the swing phase acting as braking mechanism
- Short-lived power gen as knee starts to flex, concentric contraction of the hamstrings (co-contract), + the release of energy stored in the ligaments of the extended knee
- GRF vector lies behind the knee causes an extensor moment generated by the quad muscles that contract eccentrically, absorbing power (K1) to limit speed + magnitude of flexion
8
Q
KNEE - midstance
A
- Quads eccentrically to control rate of knee flexion via knee extension moment & power absorption (K1) –> 1st peak of flexion
- Knee extends initially through concentric quadriceps via knee extensor moment w/ power gen (K2)
9
Q
KNEE - terminal stance
A
- Peak of extension
- Rectus femoris eccentric to prevent flexion occurring too rapid
10
Q
KNEE - pre-swing
A
- Knee extension moment, rectus femoris eccentric absorbs power prevent excessive knee flexion
11
Q
KNEE - Initial to mid
A
- Knee flexion primarily due to hip flexion .: pendulum no muscle contraction
- Knee continues to show a small knee extensor moment while the knee is still flexing, power absorption occurs (K3) as rectus femoris (part of quadriceps prevents the knee from flexing too rapidly)
12
Q
KNEE - swing to terminal swing
A
- Increasing knee flexor moment generated by eccentric contraction of the hamstrings w/ power absorption (K4) to prevent abrupt hyperextension = slow down that rate of knee extension
13
Q
HIP - loading
A
- Hip extensor moment at the hip produced by contraction of the hip extensors (glut max + hamstrings)
- As the hip joint moves in the direction of extension, these muscles contract concentrically + generate power (H1)
14
Q
HIP - midstance
A
- Hip extends as body moves over limb via hip extensor moment w/ power generation (H1)
- Concentric gluteus maximus & hamstrings stops as hip extension via inertia & gravity
15
Q
HIP - terminal stance
A
- Small but increasing hip flexor moment, thought to be due to a combination of adductor longus + rectus femoris contraction, stretching of ligaments and gravity as the hip moves into extension w/ a resulting power absorption (H2)
- As the direction of hip motion reverses from extension to flexion, power absorption (H2) is replaced by power generation (H3)
