The key to WBV is gravitational force, explains Brian Lyons, who manages training and education for Power Plate, one of the most established WBV brands. According to Lyons, each time the WBV platform shifts, the user's muscles reflexively contract because the body thinks it's falling. But don't throw out your sneakers just yet. “It's not a cardiovascular machine,” says Lyons. “It's another tool in your toolbox.”
The big improvement over traditional workouts, says Lyons, is efficiency: “Doing this for 20 minutes is the equivalent of an hour of strength training.”
Although some studies have shown that exercises using a Power Plate are effective in reducing cellulite, Tracy Maltz, assistant chief of outpatient physical therapy at New York—Presbyterian Hospital, greets claims about WBV with a groan. She says many of the studies cited are too small and warns that the machines shouldn't be used by pregnant women or people with blood clots, which could get dislodged. “But if someone believes it works, then why not?” she says. “I don't think there are any negative side effects.”
Surely Martha Mitchell, a TV director who has been doing WBV twice a week for six months, doesn't see any. “Within about three weeks I noticed that my arms were stronger and my stamina was better,” she says of her 18-minute WBV routine, which includes squats, abdominal holds and push-ups.
For some, even that much exertion is too much. Barile recalls one client who was in town from Tokyo: “I started leading her through the session, and she said, ‘Why are we doing this? In Japan we just stand there.’”