Posterior Chain Active Lengthening Simple. Foundational. Essential. Sit on any surface chair, bench, block, doesn’t matter. Lift one leg and rest the ankle across the opposite knee. Now sit tall - extend your lumbar spine, lift your chest and hinge forward from the hips, not the back. 1️⃣ Biomechanics As you hinge from the pelvis, the femur externally rotates while the hip flexes. This lengthens the deep posterior chain: Glute max, glute med, glute min Piriformis Gemelli obturator internus (ever