Week 6 - Mechanics, analysis & training of sitting & standing

Question 1

Kinematics

Answer 1

What we can see - joint angles, position of joint, speed of movement

Question 2

Kinetics

Answer 2

Forces that cause what we see

Question 3

Sitting kinematics: Reaching Sideways

Answer 3

Weight moves in direction you’re reaching

- More weight onto butt when reaching sideways + more weight thru feet reaching fwd.

Question 4

Sitting kinematics: Reaching down to a cup

Answer 4

• Trunk needs to move fwd. so quite a bit of weight thru feet.
• Trunk moves in direction of reach + loading leg in direction of reach

Question 5

60% reach

Answer 5

Only arm moves

Question 6

100% reach

Answer 6

Trunk moves first by flx. at hip + then arm moves

- Arm didn’t move full length, bent elbow allows for more range to move/do tasks)

Question 7

140% reach

Answer 7

Moved arm first + then trunk

- At larger distance is when people start to put more weigh thru feet

Question 8

Ipsilateral reach

Answer 8

Load that leg (same side)

Question 9

Forward reach

Answer 9

Even weight

Question 10

Reaching across

Answer 10

Load the leg you are reaching to

Question 11

Thigh support length

Answer 11

25%, 55%, 85%

Question 12

What happens when you decrease thigh support?

Answer 12

Makes it harder, you increase force thru feet especially when reaching ipsilaterally

Question 13

Muscle activity when reaching in sitting

Answer 13

(1) Tib Ant: displaces body to prep shank fwd.
(2) Tib Ant. turns off + soleus turns on to control the prog. fwd. + works concentric. to bring us back
(3) HS (bi.fem) are also working

Question 14

Other adaptive strategies in sitting

Answer 14

Using arm for support, trunk/legs shift, sh’ hiked, foot not in contact w. ground, hip ER/abd., foot inverted/everted

Question 15

Standing kinematics

Answer 15

Movement @ ankles toward object of reach

- Can only reach about 120% of arm’s length, after that you need to bend @ hips or take a step

Question 16

Centre of Pressure (CP)

Answer 16

Tracks towards the moving side in order to push the CM across to the new support side in a sideways reach

Question 17

Sitting kinematics (important components)

Answer 17

• Initial alignment: 100% thigh support, ankles plantargrade
• Feet/knees close together
• Weight evenly distributed
• Flx. of hips w/ ext. of trunk
• Head balanced on level sh

Question 18

Reaching in sitting kinematics (important components)

Answer 18

• Shift head, arms, + trunk toward the object by moving @ hip
• Load foot/feet which is/are ipsilateral to the direction of reach

Question 19

Adaptive strategies in sitting/reaching in sitting (important components)

Answer 19

• Wides BoS
• One/both hips ER + uses arms for support
• Shifts weight onto intact buttock/foot
• Flexes fwd. when task requires body weight shifted sideways

Question 20

Impairments you might see with standing

Answer 20

Loading opp leg (good leg) due to either adductors, soleus, quad, hip ext. not being strong enough

• Fully extending arm rather than shifting body + protracting sh’ too much
• Weakness in hip ext., knee ext., PF, add., coordination, sensation.

Question 21

BoS + alignment of hips, knees, + ankles of sitting still in sagittal plane

Answer 21

Hips - flexed
Knees - flexed
Ankles - plantargrade, slight DF
BoS - Butt, thigh, + feet

Question 22

Weight distribution, BoS + view of sh/hips of sitting still in frontal plane

Answer 22

Weight distribution - even
Shoulders - levelled
Hips - Levelled
BoS - Knees/toes in line with hips