The stoop lift is preformed primarily by extending the hips and lumbar region while the knees remain slightly flexed (see Figure 10-36,A). This lifting strategy is associated with greater flexion of the low back, especially at the initiation of the lift. By necessity, the stoop lift creates a long external moment arm between the trunk (and load) and the low back. The greater external torque requires greater extension forces from the low-back and trunk extensor muscles. In combination with a markedly flexed lumbar spine, the stoop lift can create large and possibly damaging compression and shear forces on the discs.