For a straight-leg test for low back pain, you lie on your back with both legs straight. Your health professional raises one of your legs upward, keeping the knee straight.

• If you have pain down the back of your leg below the knee when your leg is raised, the test is positive (abnormal).
• If doing this test on the unaffected leg causes pain in the affected leg, it is more likely that you have a herniated disc. This is known as crossover pain.