A growing body of evidence suggests that one of the strangest pieces of equipment you're likely to find in a gym – vibration platforms like the Hypervibe – can indeed be effective in building muscle and losing weight. Contrary to what their name suggests, the fundamental purpose of these machines isn't to vibrate someone, says Gabriel Ettenson, a Boulder, Colorado-based physical therapist. "They simulate higher levels of gravity, or increase G-forces, through a plate that oscillates up and down at varying intensities," he says.

These simulated G-forces cause your muscles to contract thousands of times per minute, a passive workout that forces your body to become leaner to deal with the constant force. Simulated G-forces can also help build bone density, boost circulation, and improve balance, says Ettenson, adding that vibration platforms have also proven effective in helping people with osteoporosis and muscular disorders.

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According to Ettenson, the machines are most useful when you do movements on them. But here's the biggest catch – and the reason why vibration training has gotten a bad rap: There's a huge discrepancy is the quality of platforms out there. Many, according to Ettenson, are completely ineffective.

"On one end, there are extremely expensive, cutting-edge-engineering vibration platforms," he says. "On the other end are junky platforms that are the worst gimmicks you could imagine." And research shows that the quality gap is not just perceived. If you survey the more than 600 studies on whole-body vibration, you'll see a mixed bag of results. But when you consider which types of platforms were used in each trial, the results are overwhelmingly positive for top-quality, high G-force machines. "Most 'failed' studies were conducted on sub-par machines, and that's why they failed to produce any substantial results," Ettenson explains. "Of the tremendous number of 'positive' studies, 85 to 90 percent were done one particular platform called the Galileo, a high G-force machine."

Ettenson says that as more fitness professionals are learning the differences between platforms, they are coming back around to the idea after initially dismissing it. "Health clubs had been pretty closed off to vibration training because manufacturers put chintzy platforms in gyms early on, which gave people a bad taste," he says. "Plus, the claim made by many of those manufacturers – ‘It's equal to an hour at the gym' – infuriated trainers and other fitness professionals. Rightfully so. The research is quite clear that vibration platforms offer an additional benefit, so it's more accurate to say that exercise done on a platform will be more beneficial than the same exercise off the platform."