Use a static analysis to compare a leg-lifting technique with a back-lifting technique when lifting a box from the floor. In both cases, the upper body weight is 530 N, and the box is 280 N. The upper body moment arm from the L5/S1 disc is 0.130m for the leg-lift and 0.210 m for the back- lift. The box moment arm from the L5/S1 disc is 0.270 m for the leg-lift and 0.490 m for the back-lift. The surface of the sacrum is tilted 36 from the horizontal during the leg-lift and 460 during the back-lift. The erector spinae moment arm is 0.060 m. 13. What is the force that is developed in the erector spinae muscles for the leg lifting technique? A. 1148 N B. 1260 N C. 2408 N D. 2992 N 14. What is the force that is developed in the erector spinae muscles for the back lifting technique? A. 1855 N B. 2287 N C. 4142 N D. 5308 N