Week 6 (Sitting and Standing)

Question 1

Kinematics during sitting: at 60% reach, what moves?

Answer 1

Only arm moves, minimal hip flexion or trunk movement

Question 2

Kinematics during sitting: at 100% and 140% reach, what moves?

Answer 2

Hip flexes to transport trunk and arm towards cup

Movement at HAT segment at hip towards object

Question 3

Kinetics during sitting: the further the reach, the more…

Answer 3

Load through the feet

Question 4

Muscle activity in sitting and reaching

Answer 4

Tibialis anterior contracts prior to ant. deltoid > soleus, quadriceps, biceps femoris contracts after to control the forward movement

Question 5

Muscle activity in reaching forward when sitting

Answer 5

Tibialis anterior contracts > soleus > quadriceps and adductors (control and push down with extensors)

Question 6

Muscle activity in reaching sideways when sitting

Answer 6

Ipsilateral hip, knee and ankle extensors

Question 7

Muscle activity in reaching across when sitting

Answer 7

More soleus when going across

Question 8

Important components: sitting

Answer 8

• Feet and knees close together
• Head balanced on level shoulders
• Weight evenly distributed
• Flexion of hips with extension of trunk

Question 9

Important components: reaching in sitting

Answer 9

• Shift HAT towards object by moving at hip

- Load foot or feet which is/are ipsilateral to direction of reach

Question 10

Adaptive behaviours: sitting

Answer 10

• Wide BOS
• Shifts weight onto intact foot/butt
• Flexes forward when task requires BW should be shifted sideways
• Shuffles feet
• Uses arm for balance prematurely
• Avoids threats to balance

Question 11

Kinematics: standing and reaching

Answer 11

• Movement of HAT segment at ankles towards object of reach

- Can only reach 120% arm’s length before we have to bend at the hips or take a step

Question 12

Important components: standing

Answer 12

• Feet few inches apart
• Head balanced on level shoulders
• Weight evenly distributed
• Hips in front of ankles

Question 13

Important components: reaching in standing

Answer 13

• Shift HAT towards object by moving at ankles

- Load foot/or feet ipsilateral to direction of reach

Question 14

Clinical measures: standing

Answer 14

• Timing standing unsupported
• Berg balance test
• Step test
• Functional reach

Question 15

Adaptive behaviours: standing

Answer 15

• Widens BOS
• Shifts weight onto intact leg
• Flexes at hip and/or protracts at shoulder instead of dorsiflexing at ankles in reaching forward and moves trunk instead of moving at hips and ankles when reaching sideways
• Takes a step prematurely
• Shuffles feet
• Uses arm for balance prematurely
• Avoids threats to balance by reducing movement speed and amplitude, holding stiffly or holding breath

Question 16

Kinematics during standing

Answer 16

Movement of HAT segment at ANKLES towards object of reach

Question 17

Kinematics of standing: what % before we have to bend at hips or take a step

Answer 17

120%