Lifting Analysis DR AYESHA BHATTI BSPT PPDPT PPTA

Lifting Analysis DR. AYESHA BHATTI BSPT, PPDPT. PPTA

Definitions: l Low back. l Pain. l Prevention. (types)

Lifting Essential part of everyday life l Correlation with variety of Musculoskeletal injuries especially back pain l High Financial cost l Workplace education and design by medical professionals as well as Ergonomists for prevention l

The Biomechanics Of Lifting l l l Stress Compression, shear, and tension Training the workers to lift in a biomechanically safe manner

Stoop lift

Squat Lift

Semi-Squat Lift l Greater anterior tilt of the pelvis with this approach in comparison with the other lifts, promotinglumbar Lordosis

Freestyle Lift l 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 l Trunk Kinetic Lift The trunk kinetic lift is characterized by a sudden extensor moment of the knees before the lift

Load Kinetic Lift l l 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: l l l Comparison of various lifting techniques At L 5/S 1 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: l 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. l

l l 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

l Increased angulation: l 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.

l Soft tissue compliance l 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 l l

B) Physiologic Response l l l Oxygen uptake/consumption, %VO 2 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 l Rating of perceived exertion (RPE), a subjective measure, rates the individual’s own awareness of the effort required to perform a particular activity l 90% of the subjects rated the squat lift as more fatiguing than the stoop lift

l Another subjective measure of individual lifting tolerances uses maximum allowable weight (MAW). Maximum allowable weight (MAW) measure of individual lifting tolerances l researchers reported that MAW greater for the stoop than for the squat lift. l When comparing the squat and semi-squat MAW, preferring the semi squat over the squat. l

l l 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

l l l 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

l l 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 l v v v Compression at the L 5/S 1 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: l l l 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 L 5/S 1 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 l Ensure the placement of a secure hand couple l Maintain a degree of lumbar Lordosis at the initiation and during the lift l Use the lifting technique that is most applicable to the situation l

Pushing & Pulling l l l 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

l Handle height and hand placement. l 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.

l l 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 L 5/S 1 joint when pulling as compared with pushing. l As result of the increased moment and flexed posture (at the waist) inherent with pulling as opposed to pushing

l 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 l Once the risk factors have been identified, it is therapist’s mission to control the frequency, severity, and, if possible, presence of the risk l