Seated Forward Fold
How to do it
Sit with both legs extended in front. Flex the feet so the toes pull toward you. Inhale, lengthen the spine; exhale, hinge forward from the hips. The chest reaches forward over the thighs — not the chin toward the knees. Hands can rest on the shins, the feet, or the floor outside the feet. Bend the knees as much as needed to keep the spine long. Hold for several long, slow breaths.
Why it's good for runners
A long passive hamstring stretch is one of the most useful things a runner can hold for two minutes. Seated Fold is the canonical version, plus you get a parallel release in the lower back as the spine drapes forward. Easy to do in front of the TV or before bed — it doesn't need warmth or warming up.
Common mistakes
The classic mistake is grabbing the feet and yanking — that turns a passive hamstring stretch into an active spinal flexion stretch. Don't do that. Bend the knees, keep the spine long, and let gravity work. If you can't fold without rounding the upper back, sit on a folded blanket so the hips elevate above the knees.