Why the Lagree Shake Means Your Workout Is Working              Shake Zone [SHāk-zōn]                   The place where you go low, go slow, close your eyes, picture yourself                   strangling your instructor (lovingly, of course), breathe deeply, and change your body. If you’ve ever wondered why your muscles start trembling halfway through class, you’ve entered what we call The Lagree Shake Zone. At Studio Physique in St. Petersburg, whether it’s your first class or your