When an African or Indian village woman carries a heavy weight on her head (fig. 5-3), she is not passive under that weight, which would cause her discs to compress. Rather, she actively engages her inner corset ['contracting certain muscles in your abdomen and back']; her torso becomes more slender and her spine becomes longer. In this way she protects her discs from the weight she carries. ... Medical literature documents that in certain populations, such as the Bhil tribe of Central India, the discs of a 50-year-old look very similar to those of a 20-year-old (fig 5-5). The proper and frequent use of the inner corset muscles is perhaps why these populations experience virtually no disc degeneration as they age.