[Expert Solution]: Use a static analysis to compare a…

Use a static analysis to compare a leg-lifting technique with a back-lifting technique when lifting a metal block from the floor. In both cases, the upper body weight is 315 N, and the metal block weight is 190 N. The upper body moment arm from the L5/S1 disc is 0.11 m for the leg-lift and 0.16 m for the back-lift. The metal block moment arm from the L5/S1 disc is 0.28 m for the leg lift and 0.38 m for the back-lift. The surface of the sacrum is tilted 25 from the horizontal during the leg-lift and 45 during the back-lift. The erector spinae moment arm is 0.045 m.