This is an excerpt from Run Healthy by Emmi Aguillard,Jonathan Cane & Allison L. Goldstein.
If you are feeling any radiating pain (starting up in the hip and shooting down the leg) or have dealt with sciatica in the past, nerve glides or neural mobilization techniques are another useful tool in the toolbox. Rather than stretching the muscle, the goal is to mobilize the sciatic nerve as it runs through the hamstring muscle belly. Start by lying on your back and bending the knee of the affected leg toward your body, wrapping your arms around your thigh (figure 13.4a). Next, try to straighten your leg as much as you can by extending your knee (your foot should move toward the ceiling; figure 13.4b). Once the leg is extended as far as it will go, pull your toes toward your face (dorsiflexion; figure 13.4c). You should feel a stretch up the back of your leg. Next, relax your foot back into plantar flexion, and then lower your knee back down. Repeat in this order no more than 10 or 15 times; more than that can irritate the area.