Chapter 4: Activity Limitations (sit to stand)

Question 1

Definition of Sit to stand

Answer 1

the transitional movement to an upright posture, requiring the movement of the CoM from a stable position to a less stable position over extended lower extremities

Question 2

What is the importance of being independent in STS?

Answer 2

A fundamental prerequisite for daily activities: key to independent living
Proxy measure of overall physical activity
Mean STS: 33-71/ at least 45

Question 3

what are the phases in a STS cycle?

Answer 3

1) flexion momentum
2) momentum transfer
3) extension
4) stabilization

Question 4

Describe the Flexion Momentum phase

Answer 4

Begins with the initiation of movement and ends just before the thighs lift off from the chair (seat off)

Question 5

Describe the momentum transfer phase

Answer 5

From seat off and continues with the anterior and upward displacement of the CoM
anterior translation of CoM brings it above the CoP to achieve a Quasi-static stabile posture

Question 6

Describe the extension phase

Answer 6

Initiated just after maximal ankle dorsiflexion is reached and continues until hips ceases to extend

Question 7

Describe the stabilisation phase

Answer 7

Begins just after hip extension velocity reaches 0deg/s and continues until all motion associated with stabilisation from rising is achieved

Question 8

How far does the CoM deviate in stroke patients, compared to normal patients?

Answer 8

78% before seat off

50% after seat off

Question 9

Describe the muscle activation when affected leg is placed behind?

Answer 9

Muscle Extended position Elevated position
TA Increased activation by 29% Increased activation by 51%
Quadriceps Increased activation by 34% Increased activation by 41%

Question 10

describe the muscle activation sequence during STS

Answer 10

1. Tibialis anterior
   Stabilise the feet before beginning the forward body movement
2. Knee and hip extensors
   Reach peak activity at seat-off
3. Iliopsoas and quadriceps
   Initiate hip flexion + quads stabilise the knee and allow their extension
4. Hamstrings
   Decelerate forward hip flexion after seat-off
   Initiate hip extension
5. Tibialis anterior
   Provide DF torque to balance the forward movement and maintain the CoP in posterior position under the feet
6. Gastrocnemius and soleus
   At the end of STS, they activate to control the body’s forward transition

Question 11

How far does the CoM deviate in stroke patients, compared to normal patients?

Answer 11

78% before seat off

50% after seat off

Question 12

Describe the weight distribution in stroke patients during STS

Answer 12

Sit to stand Stand to sit
Stroke, non-fallers 29% BW 28% BW
Stroke, fallers 24% BW 26% BW

Question 13

how much does weightbearing increase the affected leg is placed behind?

Answer 13

14%

Question 14

Describe the CoM transition during STS

Answer 14

Flexion momentum: moves forward and hits max velocity at preparatory phase

momentum transfer + extension: Vertical movement and it’s velocity continues to accelerate. Reaches maximum in mid extension phase

Stabilisation; Decelerates progressively until 0, standing is achieved

Question 15

Describe the weight distribution in normal individuals during STS

Answer 15

Flexion momentum: 85% under thigh, 15% under feet
Extension: 52% under the feet
Stabilisation: 100% under the feet

Question 16

What assessments are done for STS?
What is the MCID for each?
what is the mean score of stroke patients?

Answer 16

5reps STS; 30s chair stand test
2.3sec; 3reps
12sec (do fall assessment), 16sec (stroke faller); 9.8reps