The AMA Guides provides an accessory straight leg raise (SLR) validity test for lumbar spine flexion measurements. This accessory test is used when the lumbar flexion motion is less than 65° for women and less than 55° for men. The validity test compares the sacral hip flexion and extension angles to passive straight leg raising measurements. The difference between the sum of sacral flexion and extension and the tightest straight leg raise must be less than or equal to 15° for the lumbar flexion test to be valid. (See page 406 of the Guides for more information on the accessory validity test.)