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Back Mechanics. Presented by QBE Loss Control Services. Back Injuries Statistics. 25% of low back injuries account for 95% of costs of low back injuries NIOSH- 70% of general public will have back pain in their lifetime 80% of back pain caused by inadequate exercise - PowerPoint PPT Presentation
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Back Mechanics
Presented by QBE
Loss Control Services
Back Injuries Statistics• 25% of low back injuries account for 95%
of costs of low back injuries
• NIOSH- 70% of general public will have back pain in their lifetime
• 80% of back pain caused by inadequate exercise
• Back injuries account for 25% of all WC claims and 33-44% of all WC costs
Spinal Column
The spine is made up of 33 vertebrae. The upper 24 vertebrae are separated by a jelly filled layered ligaments called disks. These disks act as shock absorbers for the spine.
The facet joints are the back part of the vertebrae that form the channel for the spine.
The lumbar region are the five large vertebra composing the lower back, allowing the back to bend forward and back.
Spinal Column
Discs and Force
Herniated Discs
Lower Spine
Spine Range of Motion
0 10 20 30
L5-S1L4-5L3-4L2-3L1-2T12-
T11-12T10-11T9-10T8-9T7-8T6-7T5-6T4-5T3-4T2-3T1-2
C7-T1C6-7C5-6C4-5C3-4C2-3
Flexion/Extension
Degrees
Spine Range of Motion
0 10 20 30
L5-S1L4-5L3-4L2-3L1-2T12-
T11-12T10-11T9-10T8-9T7-8T6-7T5-6T4-5T3-4T2-3T1-2
C7-T1C6-7C5-6C4-5C3-4C2-3
LateralFlexion
Degrees
Spine Range of Motion
0 10 20 30
L5-S1L4-5L3-4L2-3L1-2T12-
T11-12T10-11T9-10T8-9T7-8T6-7T5-6T4-5T3-4T2-3T1-2
C7-T1C6-7C5-6C4-5C3-4C2-3
Rotation
Degrees
Back Mechanics
Danger Zones
Anatomy of Proper Lifting
Anatomy of Proper Lifting
If you are out of physical shape can also result in increased loads when we improperly lift.
Balance of Forces
Balance of Forces
Without Weight
? lb x 2 in = (65 lb x 9 in) + (15 lb x 15 in) + (25 lb x 24 in)
? X 2 in = 1410 lbs
Force on Back = 705 lbs
Torso Arms Head
Balance of Forces
With Weight
? lb x 2 in = (65 lb x 9 in) + (15 lb x 15 in) + (25 lb x 24 in) +(20 lb x 36 in)
? X 2in = 2130 lbs
Force on Back = 1065 lbs
Torso Arms Head Object
Equivalent Forces
Relative Disk Pressure
40
100
150150
190
0%
20%
40%
60%
80%
100%
120%
140%
160%
180%
200%
Position
Reclining
Standing
Sitting
StandingLeaningForwardSitting LeaningForward
Relative Disk Pressure Sitting Posture
100%
85% 85%75%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Position
Sitting Upright
Sitting Uprightw/Low BackSupportReclining
Recliningw/Low BackSupport
