Muscles in the lower leg and foot especially calves (the hearts of the legs) pump energy up the leg from the ground. Thighs support the torso; hamstrings hug the Earth (pull it up into the dantien). Hips and sacroiliacs relax so that the pelvis floats free rather than being held rigid. Then energy from the Earth passes into the upper body unimpeded. When you get it right the whole body will feel light and alive, and the heart will lift naturally – out of itself and beyond itself.