Would You Like a Shake With That Workout?

The idea seems sort of silly, just another exercise gimmick. Stand for a few minutes on a platform that vibrates. Get off and try to do some weight lifting — squats, for example. Or try a short sprint. Or see how high you can jump. You are somehow supposed to be able to lift heavier weights, sprint faster, jump higher. But maybe it’s not so silly, exercise physiologists say. Although they don’t really know why vibrations should work, researchers report that they actually seem to slightly improve performance in the few minutes after a person gets off the machine. The problem, though, is that there is little consensus on how fast the vibrations should be or in what direction platforms are supposed to vibrate. Some studies have failed to show any effects from vibrations. And then there is the question of what exactly vibrations are doing to muscles and nerves. “It certainly is intriguing, and a large portion of the evidence would support that something is happening,” said Lee E. Brown, director of the Center for Sports Performance at California State University, Fullerton. But he added, “We are still trying to figure out exactly what the mechanism is.” Meanwhile, several companies make the vibrating platforms, and they are being used at gyms and by some athletes. One company, Power Plate, proclaims that stars like Serena Williams and Justin Morneau, of the Minnesota Twins, train with its device. A testimonial for another company, Wave, says the United States ski and snowboard teams used its vibrating plates in training for the 2010 Winter Olympics. But researchers are wary. Experts who have tried the platforms describe them in different ways. The sensation is nothing like using a jackhammer, said Hugh Lamont, a sports biomechanist at East Tennessee State University. Most vibration plates move no more than 50 times a second and feel like the vibrations in a seat over the wheel hub on a bus, Dr. Lamont said. Others say the vibrations remind them of downhill skiing — they get the same sort of the rattling in their legs and feet. For Jeffrey M. McBride, an associate professor of biomechanics who is director of the neuromuscular laboratory at Appalachian State University in Boone, N.C., the word that comes to mind is “weird.”