SHAKING YOURSELF FIT CAN BE DANGEROUS

Whole body vibration (WBV) exercise involves standing (or doing
movements such as squats) on a vibrational platform. These
machines have been promoted heavily at various fitness conventions

that I have attended.

For the most part, it is a passive exercise that involves no running,
lifting or sweating. All the benefits come (supposedly) come from
doing this in only 10 to 15 minutes a day. One website says “you
will look slimmer, get stronger, feel more energetic, and move with
more confidence, with minimal effort.” Other reports say that this
mode of exercise improves bond density, reduces cellulite and stress
hormones, and elevates mood, among other benefits. Really? Not so
You can find the machines in some gyms, exercise studios, and
rehab centers, or you can buy one for home use (costing $250 to

$1,000 and up).

The mechanism that might account for the purported benefits isn’t
entirely clear, but the oscillating vibrations trigger an involuntary
reflex in the body that causes muscles to rapidly contract. The
part of your body closest to the platform is impacted more by
the vibrations, so if you are standing (as is typical) then your legs

benefit the most.

Studies have been done on the “presumed” results. Both on animals
and humans. Results have been inconsistent and/or hard to compare
for several reasons. Researchers have often used different devices
(which vibrate at different intensities and in different directions)
different training regiments (with subjects standing versus moving
on the platform, for example), and different populations (old or
young, fit or unfit, healthy or ailing. No one knows what an optimal
protocol is or what long-term effects – good or bad – WBV may
have. Also, the high-quality professional machines used in research
may not be comparable to less-expensive ones sold for home use,
which vary widely in quality. Here are some of the findings.
Muscle fitness – In a small study in the European Journal of
Sport Science in 2013, people (average age 81) who did both static
(standing in place) and dynamic (moving) exercise on a WBV
platform for nine weeks showed improvements in both upper- and
lower-body strength. Another study, this year in Therapeutics and
Clinical Risk Management, found that six months of dynamic WBV
training (with squat exercises) increased muscle power in older
people with osteoarthritis. Younger muscles seem to benefit too.
Another study in PLOS ONE this year found that fit young adults
who trained on a vibrating platform for four weeks had greater
muscle endurance than those who did the exercises on the floor.
Balance – Most studies have shown that WBV can improve balance
in frail elderly subjects, postmenopausal women, and people with
medical conditions that can limit movement, as well as in young,
healthy people. For example, twelve weeks of WBV training
improved balance in people with diabetes in a 2013 study in the
Archives of Physical Medicine and Rehabilitation.
Bone health – Low-intensity vibration therapy is good for lab
animals’ bones, but studies in people have had mixed results. One
this year in the Journal of Science and Medicine in Sport found
no bone improvements in men and women (average age 75) who
did squat exercises on a WBV machine three times a week for 11
weeks. Another, in the Annals of Internal Medicine in 2012, found
no benefits in postmenopausal women over a year. In contrast, some
earlier research had positive results, with one study finding the most
improvement in older people, particularly women and those with

osteoporosis.

Body fat- A pilot study this year in Clinical Interventions in Aging
found that WBV with squats, done three times a week for eight
weeks, had no effect on body composition in sedentary older women.
Other studies have shown that if vibration therapy increases
metabolism and burns some calories, it doesn’t match the intensity
of traditional aerobic exercise needed to reduce body fat.
Vibration isn’t always good for everyone. Especially the elderly
and infirmed. Chronic and/or high-intensity occupational exposure
has been implicated in back and joint pain, nerve damage, blurred
vision, and other problems. Pain, leg numbness, and nausea have
been reported in some WBV studies. Be aware that a study last
year found that two of the three WBV devices analyzed exceeded
the daily limit set by the International Standards Organization,
delivering “vibrations not considered safe for even seconds, much

less minutes, of daily exposure.”

People who should definitely avoid WBV training, are pregnant
women and those with a retinal detachment, pacemakers, cochlear
implant, or recent hip or knee replacement. Manufacturers of
devices further warn against their use by people with severe
osteoporosis, severe cardiovascular disease, cancer, and epilepsy,

among others.

The promotional benefits of WBV training are far from proven. It
is not a replacement for conventional workouts, including aerobics
and strength training.