27_28- back injuries in workplace + sitting Flashcards
what are the two calculations to determine risk of injury during lifting
- recommended weight limit
2. Lifting Index
what is recommended weight limit (RWL)
- 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
what is Lifting index and what isn’t a great result
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
when is a container considered less than optimal
frontal length >16inches height >12inches rough or slippery surfaces sharp edges asymmetric COM unstable contents the use of gloves
When if the living index for origin and destination not great
when result is over 1
LI origin= object weight/RWL origin
ideal frequency for lifts
1 lift every 5 mins for <1hr
higher frequency cyclic loading results in (2)
- larger creep development
- longer rest period required
higher frequency loading induces what
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
what is a risk factor for upper quadrant muscle pain
a combo of extreme cervical and thoracic angles
prolonged flexing causes what in terms of disk pressure
posterior migration
sitting in a flexed lumbar posture for prolonged periods may result in
- creep in post lumbar tissues
2. acute neuromuscular disorer
what seat recline angle has lowest pressure on disk
105degrees
does sitting cause lbp
not by itself
-but sitting >half work day in combo with whole body vivbration +/or awards postures does increase
how long did creep take to recover in solomon’s 2009 study
more than 2 hrs
in pain developers sitting what did they find
higher cocontraction
-tended to increase over time and sig correlate to pain development
TMj and sitting protes
- week, long deep neck flexors
- short/tight neck extenssors
- upper cross syndrome
take home messages for sitting loads
vary pos
get up and move frequntly
design the job and env to encourage mvmt
probs w large seat pan depth
- lumbar creep due to hams pulling pelvis into post tilt
- pressure on pop fossa
- prolonged back mm contraction to maintain posture
chair backrest on paraspinal mm activation/ lbd
- moderate evidence that backrests reduce paraspinal mm activation
- Limited evidence that backrests reduce LBD
what is a forward lean seat pan better for
those with pain worse in flexion
sitting time and LBD
sitting time was positively associated w LBP intensity
stability ball sitting results
- no statistically sig difference for pain/disability in either group
- did improve core endurance in the sagittal plane
is crossing legs bad for you
no high level research to suggest so
-so no good answer but changing pos every 20 mins is like a good idea
backpack recommended weight
CCA recommends max of 10%
