Have you ever heard of a shoe claiming it can get you in shape? And what about the latest fitness craze — you vibrate and get fit? Possible? Here are a few of our latest investigations and what we found.

FITFLOPS: WWW.THEFITFLOP.COM

Claims: According to the manufacturer: "It's the flip-flop with a gym built in. ... FitFlops have been shown to trigger increased gluteal muscle response, increased hamstring response, increased rectus femoris (thigh) response and increased calf muscle response. ... So just by wearing a pair of FitFlops you'll get more exercise while doing just exactly what you're normally doing."

Facts: The shoe "appears to have considerable shock-absorbing materials at the heel, a midsole that controls mid- and rear-foot pronation, and a stiff toe portion allowing efficient transfer of energy at terminal stance (all good things to absorb the shock and correct common, minor biomechanical problems)," says H. James Phillips, a professor of physical therapy at Seton Hall University.

Do FitFlops produce more glute and quad activation than regular shoes? "Given the propensity for bad posture and gait, many individuals (especially women who wear high heels) have little glute engagement in standing and walking, so their glutes are very weak. The wobble effect of shifting pelvic position and weight onto the heels will increase glute activation. If the glute is weak, even a slight increase in glute activity may feel like a butt-blaster," says Fabio Comana, an exercise physiologist for the American Council on Exercise.

Will this tone and trim your legs? "Theoretically the muscles must work a bit harder than they would with more conventional shoes," says Phillips.

Fiction: "Now comes the 'stretch.' While a small increase in muscle recruitment may occur, the leap to claiming that it will 'trim and tone' the legs and recruit 'fat-burning slow-twitch fibers' has not been demonstrated with any clinical studies," says Phillips.

"It's unrealistic to expect a flip-flop to do everything this one is claiming (from improving posture to decreasing back pain to firming the butt)," says Dr. Dina Tsentserensky, a New York City podiatrist. And while these flip-flops are probably very comfortable, according to Tsentserensky it is likely that simply wearing a sneaker or any other comfortable flip-flop with a bit of arch support and a slight heel will give you the same results.

Concerns: "While having arch support in a shoe is generally a good idea, having too much arch support can also lead to injuries of overuse in the foot. In addition, people have varying arch sizes, and what works for one person may lead to injury in another," says Tsentserensky.

Bottom Line: It's a comfortable shoe that may promote a small increase in muscle recruitment, but it isn't likely to produce the type of results promoted by the manufacturer, says Phillips.

WHOLE BODY VIBRATION AND POWER PLATE: WWW.POWERPLATE.COM

Claims: It creates instability in the body by using whole body vibrations — basically you stand on a plate, hold on and it vibrates. Here's what the manufacturer claims: "Power Plate employs a 20-by-32-inch body positioning plate housing a driving mechanism that evenly distributes vibrations throughout the body, accelerating and magnifying the same contraction and relaxation muscular reflexes employed when performing traditional weight training exercises.

"Power Plate utilizes revolutionary principles of whole body vibration therapy to substantially improve muscle strength and performance, flexibility, enhance critical blood flow throughout the body, expedite the recovery and regeneration of damaged tissue, and ultimately, enhance the general wellness and quality of life for individuals young and old."

Facts: There is scientific evidence that whole body vibration can help with agility, balance and fall prevention in the elderly, says Nathaniel Tindel, a New York City back surgeon, and author of "I've Got Your Back" (NAL Trade, 2007). In fact, there are more than 100 papers on the topic. Whole body vibration therapy shows promise for muscle warm-up, flexibility, knee stability and neurological controls, among other benefits, says William J. Kraemer, a professor of kinesiology at the University of Connecticut.

Vibration training works through a strong neuromuscular stimulus. An acceleration of the plate causes the body to react. "While there have been only moderate increases in size of muscle, there are strong results for the elderly and conditioned athletes in increased muscle power," says Joseph Signorile, a professor of exercise science at the University of Miami and Power Plate adviser. Muscle power is the rate at which you can produce strength — the "spring in your step." He's seen results in as little as 15 minutes per day.

Fiction: This is "not a panacea for all fitness." We still don't know exactly how to use it, when to use it, and for which populations it works best. More research needs to be done, says Kraemer.

According to Sal Marinello, a fitness expert and blogger in Milburn, N.J., "Whole vibration therapy is a gimmick, plain and simple, from the idea that standing and/or exercising on a vibrating plate will help you get fit to the expensive nature of the machines. I can't see one positive about it."

Concerns: "The Power Plate can make your body better equipped to handle the stresses of whatever sport or activity you follow, but unless you are going to be living and moving on a vibrating surface permanently, you'll need to train off the plate," says Jonathan Ross, a spokesperson for the American Council on Exercise.

Additionally, there is no documentation of any cardio benefits, says Christina A. Geithner, a spokesperson for the American College of Sports Medicine. Furthermore, Power Plate is expensive: Models range from $2,500 to $10,500, says Ross.

Bottom Line: This is potentially one tool in a fitness and exercise toolbox, but it's still too early to make broad, sweeping claims that vibration therapy will get you fit. In fact, according to Kraemer, vibration therapy will never "by itself, create fit people — that I guarantee."

Charles Stuart Platkin is a nutrition and public-health advocate, and author of "Breaking the FAT Pattern" (Plume, 2006). Sign up for the free Diet Detective newsletter at www.dietdetective.com.