Lumbar Part 5

Question 1

Muscle force (MF) is the most influential variable for determining the magnitude of the compression (reaction force (RF) on the

Answer 1

lumbar spine

Question 2

Moment arm of the extensors (D1) is

Answer 2

relatively small = 5 cm

Question 3

Biomechanics of lifting
Extensors are at a sizeable

Answer 3

mechanical disadvantage

will have to contract very strongly to overcome the disadvantage

Question 4

extensors Required to produce a force many times larger than the weight

Answer 4

of the object lifted

Question 5

How to reduce the amount of force required of the back extensor muscles during lifting:

Answer 5

Decrease the velocity of lifting
Decrease the magnitude of the external load
Decrease the length of the external moment arm (distance from axis of rotation to the object lifted)
Increase the length of the internal moment arm (for the extensors)

Question 6

Lifting rapidly requires greater muscle force and greater

Answer 6

compression and shear on joints and soft tissues in the low back

Question 7

Best to lift

Answer 7

slowly and smoothly if possible

Question 8

how can the length of the external moment arm be decreased

Answer 8

Keep object as close to the body as possible
Perform a squat lift with the object between the knees
Do not hold object away from the body

Question 9

Increasing the lumbar lordosis will

Answer 9

increase the internal moment arm

Question 10

Increasing the moment arm for the extensors allows torque to be created when lifting with

Answer 10

less muscle force required

Question 11

Best to maintain normal lumbar lordosis when

Answer 11

lifting (not exaggerated lordosis)

Question 12

Valsalva maneuver: voluntarily increasing intra-abdominal pressure by vigorous contraction of the

Answer 12

abdominal muscles against glottis (“holding your breath”)

Question 13

valsalva maneuver A rigid column of pressure is created within the

Answer 13

abdomen

Question 14

intrabdominal pressure Creates an extension torque on the

Answer 14

L spine

Question 15

intra abdominal pressure Helps decrease demand on

Answer 15

lumbar extensors when lifting

Question 16

intra abdominal pressure Lowers the compression force on the

Answer 16

L spine

Question 17

Role of Abdominal Muscles When Lifting creation of

Answer 17

intra-abdominal pressure

Question 18

Role of Abdominal Muscles When Lifting Bracing effect around the

Answer 18

lumbopelvic region

Question 19

Role of Abdominal Muscles When Lifting - Resists torsional forces created by

Answer 19

asymmetrical lifting

Question 20

attachments of transverse abdominis to thoracolumbar fascia creates a circumferential corset around the entire

Answer 20

low back region

Question 21

During inhalation contraction of diaphragm helps increase

Answer 21

intra-abdominal pressure

Question 22

Role of diaphragm when lifting
Creates a pneumatic stiffness in the

Answer 22

low back region

Question 23

To be most effective contraction of diaphragm needs to occur with contraction of the

Answer 23

abdominals and the pelvic floor muscles

Question 24

Bending forward when lifting progressively elongates

Answer 24

posterior lumbar spine ligaments

Question 25

Passive tension in posterior L spine ligaments assists with an

Answer 25

extension torque

Question 26

Full stretched ligaments generate 25% of total

Answer 26

extension torque for lifting

Question 27

best to avoid

Answer 27

full flexion of the lumbar spine

Question 28

Neutral spine position best for

Answer 28

extensor muscle performance

Question 29

Passive tension within stretched thoracolumbar fascia produces an

Answer 29

extension torque in the lumbar region

Question 30

Bending forward and flexing lumbar spine when lifting stretches the

Answer 30

fascia

Question 31

Active contraction of _______ stretches fascia

Answer 31

transverse abdominis, internal oblique, latissimus dorsi, and gluteus maximus stretches