Use a static analysis to compare a leg-lifting technique with a back-lifting technique when lifting a moderately heavy box from the floor. In both cases, the upper body weight is 480 N, and the box is 260 N. The upper body moment arm from the L5/S1 disc is 0.110 m for the leg-lift and 0.190 m for the back-lift. The box moment arm from the L5/S1 disc is 0.260 m for the leg-lift and 0.450 m for the back-lift. The surface of the sacrum is tilted 32ï° from the horizontal during the leg-lift and 42ï° during the back-lift. The erector spinae moment arm is 0.060 m.

 

1.) What is the force that is developed in the erector spinae muscles for each lifting technique?

A. leg-lift 740 N, back-lift 740 N

B. leg-lift 1127 N, back-lift 1950 N

C. leg-lift 2007 N, back-lift 3470 N

D. leg-left 2557 N, back-lift 4423 N

 

2.) What is the compressive reaction force due to the weight above the L5/S1 disc for each lifting technique?

A. leg-lift 392 N, back-lift 495 N

B. leg-lift 407 N, back-lift 357 N

C. leg-lift 628 N, back-lift 550 N

D. leg-lift 740 N, back-lift 740 N

 

3.) What is the total compressive force on the L5/S1 disc for each lifting technique?

A. leg-lift 1480 N, back-lift 1480 N

B. leg-lift 1534 N, back-lift 2307 N

C. leg-lift 2635 N, back-lift 4020 N

D. leg-lift 2949 N, back-lift 4918 N

 

4.) What is the shear reaction force on the L5/S1 disc for each lifting technique?

A. leg-lift 254 N, back-lift 321 N

B. leg-lift 392 N, back-lift 495 N

C. leg-lift 628 N, back-lift 550 N

D. leg-lift 740 N, back-lift 740 N

 

5.) Which loading situation contributes most to the external torque about the L5/S1?

A. body weight during the back-lifting technique

B. body weight during the leg-lifting technique

C. box during the back-lifting technique

D. box during the leg-lifting technique

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Status NEW Posted 08 May 2017 04:05 AM My Price 8.00

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