27_28- back injuries in workplace + sitting

Question 1

what are the two calculations to determine risk of injury during lifting

Answer 1

1. recommended weight limit

2. Lifting Index

Question 2

what is recommended weight limit (RWL)

Answer 2

• principle product of the revises NIOSH lifting equation
• RWL is the weight of load that nearly all healthy workers could perform over a substantial period of time w/o increased risk of developomh lifting related LBP

Question 3

what is Lifting index and what isn’t a great result

Answer 3

LI provides a relative estimate of the level of physical stress associated w a particular manual lifting task

LI values over 1.0 would benefit most from redisign

Question 4

when is a container considered less than optimal

Answer 4

frontal length >16inches
height >12inches
rough or slippery surfaces
sharp edges
asymmetric COM
unstable contents 
the use of gloves

Question 5

When if the living index for origin and destination not great

Answer 5

when result is over 1

LI origin= object weight/RWL origin

Question 6

ideal frequency for lifts

Answer 6

1 lift every 5 mins for <1hr

Question 7

higher frequency cyclic loading results in (2)

Answer 7

• larger creep development

- longer rest period required

Question 8

higher frequency loading induces what

Answer 8

induce larger creep
require longer rest time
prob indice larger risk for cumulative creep in the same day and from day to day
-larger creep results in increased laxity of the jt as activity goes on

Question 9

what is a risk factor for upper quadrant muscle pain

Answer 9

a combo of extreme cervical and thoracic angles

Question 10

prolonged flexing causes what in terms of disk pressure

Answer 10

posterior migration

Question 11

sitting in a flexed lumbar posture for prolonged periods may result in

Answer 11

1. creep in post lumbar tissues

2. acute neuromuscular disorer

Question 12

what seat recline angle has lowest pressure on disk

Answer 12

105degrees

Question 13

does sitting cause lbp

Answer 13

not by itself

-but sitting >half work day in combo with whole body vivbration +/or awards postures does increase

Question 14

how long did creep take to recover in solomon’s 2009 study

Answer 14

more than 2 hrs

Question 15

in pain developers sitting what did they find

Answer 15

higher cocontraction

-tended to increase over time and sig correlate to pain development

Question 16

TMj and sitting protes

Answer 16

• week, long deep neck flexors
• short/tight neck extenssors
• upper cross syndrome

Question 17

take home messages for sitting loads

Answer 17

vary pos
get up and move frequntly
design the job and env to encourage mvmt

Question 18

probs w large seat pan depth

Answer 18

• lumbar creep due to hams pulling pelvis into post tilt
• pressure on pop fossa
• prolonged back mm contraction to maintain posture

Question 19

chair backrest on paraspinal mm activation/ lbd

Answer 19

1. moderate evidence that backrests reduce paraspinal mm activation
2. Limited evidence that backrests reduce LBD

Question 20

what is a forward lean seat pan better for

Answer 20

those with pain worse in flexion

Question 21

sitting time and LBD

Answer 21

sitting time was positively associated w LBP intensity

Question 22

stability ball sitting results

Answer 22

• no statistically sig difference for pain/disability in either group
• did improve core endurance in the sagittal plane

Question 23

is crossing legs bad for you

Answer 23

no high level research to suggest so

-so no good answer but changing pos every 20 mins is like a good idea

Question 24

backpack recommended weight

Answer 24

CCA recommends max of 10%