lifting and lifting techniques:
An activity essential part of every day life
A contributing factor in the development of variety of musculoskeletal injuries
Particularly of lumber spine.
One of first and most easily applied administrative controls to prevent the high incidence of low back injuries at the work site is training the workers to lift in a biomechanically safe manner.
It is a maneuver that typically requires maximum flexion of the trunk and as near to terminal extension of the knees without locking as possible.
It requires knee flexion >90 degrees and trunk flexion <30 degrees
It shares the characteristics of stoop and squat.
Knee flexion >45 degrees and trunk flexion at apporx same angulation.
It comprises greater anterior tilt of pelvis in comparison with other lifts promoting lumbar lordosis.
Additional lifting style deserves attention.
These include freestyle lift.
This lift resembles in most respects the semi-squat but can differ from person to person.
Trunk kinetic lift
Characterized by a sudden extensor moment of the knees before the lift.
Load kinetic lift
The load kinetic lift requires a closer approximation of the load to the body just before the initial acceleration moments
Crtique of lifting tchnique.
Biomechanical Analysis of Lifting
It is generally accepted that the closer the close the load is placed to the body the more significantly diminished the resultant compressive forces to the lumber spine.
This strategy is employed more effectively in the semi-squat lift(load between the feet and knees) then with the stoop or squat lift.
Increased compression appears to be present with the stoop vs squat lift the shear forces are significantly higher during the squat lift .
Low back loading was significantly higher during squat lifting than with stoop lift when lifting from floor.
This is the result of the longer mmiment arm created by the more posterior fulcrum of L5/S1 in relation to the load being lifted during the squat lift.
Theses stressors can be bettered by decreasing the moment arm with placement of load between the feet.
As in semi squat lift rather than pure squat or stoop lift.
Foot placement is depend upon the size of the load, if the container is too wide (large) to allow for proper foot placement (greater than shoulder width Approx 30 cm)then the ideal lift would be stoop as it would result in less compressive forces.
Soft tissue compliance (lumbothoracic paraspinals & spinal ligaments) follows standard length-tension relationship during various lifts.
Supraspinous & interspinous ligamnets more effectively countered the lumbar moment during the stoop rather than squat and semi squat.
O2 uptake consumption , %VO2 max, the gold standard of energy expenditure was found to be greater with the squat lift than with stoop.