The source of the absurd improvement relied less on Voodoo than it did on vibration. Research had shown that resting a limb on a vibrating surface during stretching greatly increased the flexibility of that limb. Sands searched the literature but was surprised to find no attempts to repeat the data and capitalize on the potential advantage. Armed with $1,000, a local machine shop and an engineering intern Sands decided to make his own vibration box. The machine itself is surprisingly simple. It's shaped like a small pommel horse and shakes continuously at 30 hertz. After trials with young male gymnasts showed 400 percent improvements acutely and significant increases at four weeks, Sands felt the device was ready for Olympic prime time. Three years later, with a series of peer-reviewed publications, Sands says the effect of the machine is indisputable.