Lifting Analysis
DR.AYESHA BHATTI
BSPT, PPDPT.PPTA
Definitions:
 Low
back.
 Pain.
 Prevention.(types)
Lifting
Essential part of everyday life
 Correlation with variety of
Musculoskeletal injuries especially back
pain
 High Financial cost
 Workplace education and design by
medical professionals as well as
Ergonomists for prevention
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The Biomechanics
Of Lifting
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Stress
Compression, shear, and
tension
Training the workers to lift in a
biomechanically safe manner
Stoop lift
Squat Lift
Semi-Squat Lift
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Greater anterior
tilt of the pelvis
with
this
approach
in
comparison with
the other lifts,
promoting
lumbar Lordosis
Freestyle Lift
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lift resembles in most respects the semisquat but can differ from person to person
It is this variability that makes it difficult to
examine during controlled studies
 Trunk Kinetic Lift
The trunk kinetic lift is characterized by a
sudden extensor moment of the knees
before the lift
Load Kinetic Lift
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The load kinetic lift requires
a closer approximation of
the load to the body just
before the initial
acceleration moment.
This lift, too, is seen as a
variation of the three more
standard lifts
Critique Of Lifting Techniques
A) Biomechanical Analysis:
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Comparison of various lifting techniques
At L5/S1 lumbar moment and compressive
forces were equal for the stoop and squat
in one study
One study indicated less forces in stoop lift
as compared to squat lift
Foot placement,: is contingent on the
size of the load:
 If the container is too wide (large) to
allow for proper foot placement (greater
than shoulder width—approximately 30
cm [12 in]), then the ideal lift would be
the stoop, since it would result in less
compressive forces.
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Weight placement: It is generally accepted that
the closer the load is placed to the
body(decreased angulation & small movement
arm), the more decrease in resultant
compressive forces to the lumbar spine
Employed more effectively in the semi-squat lift
(load between the feet and knees) than with the
stoop or squat lift
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Increased angulation:
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in stoop lift—through flexion—
increased compression and shear
forces to the intervertebral disc, it
would make to prescribe the semisquat or squat technique when an
individual is required to lift heavy
objects on an occasional basis.
(four work cycle/mint), more
precisely semi squate is best in
this condition.
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Soft tissue compliance
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supraspinous and interspinous
ligaments more effectively countered
the lumbar moment (as a result of
shear or compressive forces) during
the stoop rather that the squat and
semi-squat lifts
Activation muscle modify shear
forces,(proper lordotic posture) must
be maintained.
Ideal lift is squate or semi squate
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B) Physiologic Response
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Oxygen uptake/consumption, %VO2 max, the
gold standard of energy expenditure, was found
to be greater with the squat lift than with the
stoop
Increased muscular effort in Squat and semi
squat as compared to stoop lift
Tendency to Switch from the squat and semisquat to the stoop lift because of the decreased
energy demands
C) Perceived Exertion
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Rating of perceived exertion (RPE), a
subjective measure, rates the
individual’s own awareness of the effort
required to perform a particular activity
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90% of the subjects rated the squat lift
as more fatiguing than the stoop lift
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Another subjective measure of individual
lifting tolerances uses maximum
allowable weight (MAW).
Maximum allowable weight (MAW)
measure of individual lifting tolerances
 researchers reported that MAW greater for
the stoop than for the squat lift.
 When comparing the squat and semi-squat
MAW, preferring the semi squat over the
squat.
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Response was compared of an individual
experiencing low back pain and what
adjustments are made to negotiate a lift from floor
to waist vs without back pain.
Asymptomatic group showed no preference
between the squat or stoop lift but that more than
two thirds of those with back pain (symptomatic
group) had adopted the squat or semi-squat as
their preferred lift
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The rate at which any lift is performed is
extremely important
quickly, vs steady smooth lifting … 15 %
forces
jerk lift:-avoide: Appropriate marking or
“weight coding
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The National Institute for Occupational Safety and
Health (NIOSH) define Effective hand grip and
couple in the practice of safe lifting
Secure grasp when handling an unstable load
Instability from lack of an effective grasp affect
stability of the load)--- the involuntary increased
recruitment of the core-trunk muscle groups
(erector spine, rectus abdominas, external and
internal oblique)--- increased lumbar
compressive forces
hand holes and handles on the object
Other Considerations
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Compression at the L5/S1 joint was not only indicator of
the potential for injury so also consider other factors…
Load rate
Lateral shear and torsion (side bending and twisting)
Velocity
Acceleration
Worker experience and attitudes toward the job
Poor footing and ground slope (parallel vs stepforward footing)
Incline:
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Lumbosacral moments were considerably larger
when lifting from an inclined slope compared with
a declined surface
Subsequent increase in angulations resulted in
an increased moment arm of the trunk,
hydrostatic pressure of disc, and torque at the
L5/S1 segment.
Goal of therapist is to reduce the risk of liftrelated injuries at both the work site and at home
Standards
Keep the load close
 Ensure the placement of a secure hand
couple
 Maintain a degree of lumbar Lordosis at
the initiation and during the lift
 Use the lifting technique that is most
applicable to the situation
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Pushing & Pulling
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Seemingly less threatening and more
biomechanically efficient
Resultant vectors changed from the vertical to the
horizontal axis,…… added the component of
frictional resistance when pushing or pulling.
Net joint torques at the shoulder were minimal
during pushing maneuvers but greatly increased
during pulling efforts
 Handle
height and hand
placement.
 Vertical forces were
less with the handle and
hand placement at the
lowest positions,
whereas horizontal forces
remained constant or
slightly increased as the
handle placement
became higher.
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Optimal pushing height for the
best performance appeared to
be at or about waist level
Comparing pulling with
pushing, the vector of force is
substantially higher at the
L5/S1 joint when pulling as
compared with pushing.
 As result of the increased
moment and flexed posture
(at the waist) inherent with
pulling as opposed to pushing
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The final consideration when evaluating pushing and
pulling tasks is foot placement and the avoidance of
slippage resulting from a poor coefficient of
friction (low COF)-water, oil, or other
contaminants to the surface.
Injuries secondary to these conditions can be
serious and usually result from the loss of
balance and uncontrolled acceleration of the
whole body
 Once the risk factors have been identified,
it is the therapist’s mission to control the
frequency, severity, and, if possible,
presence of the risk
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