Simply put, sciatica is pain, numbness, or tingling that radiates down one or occasionally both legs. The reason you have pain that travels down your leg is due to compression or irritation on the sciatic nerve. The sciatic nerve often gets blamed because its the largest nerve in the human body, and quite frankly its easier to tell a patient they have "sciatica" than "lumbar radiculopathy".
The source of this pain can be generated from the low back, the buttock, or even the hamstring. Most often, it is from the low back. If you have pain that travels down your leg, and often gets irritated with movements of the spine such as deadlifts, prone press ups, etc then the following video may help address that pain.
The following video is my broken down version of the McKenzie method for treating low back pain. The goal is to find 1 direction that is outlined in the video that helps relieve that pain or helps to centralize that pain.
Have a watch and let me know how it goes!