I stand. It's enough to make me want to stay in bed. I've heard that we are tallest upon waking, shortest before bed?not unlike how astronauts gain a few inches while in zero gravity and shrink when back on solid ground. But can the spine really be so malleable? Yes, says physiotherapist Clare Frank, DPT, an orthopedic specialist at Kaiser Permanente's Movement Science Fellowship in Los Angeles. The normal daily stresses of sitting and standing, plus the pull of gravity, compress the collagen-rich discs between vertebrae, causing us to lose millimeters each day. While we sleep, the fluid between the discs is replenished, plumping the discs up like a sponge in water, lengthening the spine. Starting in our forties, the discs begin to shrink permanently. Once you factor in bone loss, most people lose up to two inches by the time they're in their eighties. But that's a long way off for me, and I'm determined to be an upright old lady. So which posture path to pursue? If years of twice-weekly weight training and semiregular yoga have failed to keep me aligned, maybe I need to retrain my mind before my musculature. Frank piques my interest when she tells me she's a certified instructor in something called Dynamic Neuromuscular Stabilization (DNS), associated with the "Prague School" (unrelated to the '30s semiotic clique beloved by lit majors), a method started in the '60s by a group of Czech neurologists and physiotherapists. Taught at Prague's Charles University's Department of Rehabilitation and