Machines like this one which vibrate your body while you stand on it or exercise on it have been touted by gyms as fat-busters. Doctors give their take on their effectiveness and warn that long-term use may lead to nerve and organ damage
Yes, vibration works to help you lose fat and weight – but only if you exercise and follow a sensible diet as well.
The vibration plate machine, which has a platform that vibrates while the person stands on it, has been making its presence felt in workout studios and even homes here.
Since one brand called Power Plate was first sold here six years ago, the number of dedicated Power Plate studios here has grown to six, while that of gyms that stock these machines has risen to 10, said its sole distributor Positive Impact.
It has also sold more than 300 such machines to individuals. Each costs between $5,000 and $23,000, depending on the size of the machine.
Health and wellness retail company Oto has also developed a machine based on whole body vibration. A spokesman said it has sold 25,000 units of the FLABeLOS, at $1,198 each, to individuals here since 2007.
The Power Plate studios combine pilates, kickboxing and core, stretch, toning and cardiovascular exercises with the vibration plate machine. Classes cost between $25 per group session and $90 for a one-to-one session. Each session typically lasts 40 to 45 minutes.
The principle behind this is something called “acceleration training”, in which you need a shorter amount of time to burn the same amount of calories.
Exercising on a vibration plate may also have positive effects on strength, stability and bone density, said doctors and Power Plate master trainer Tay Koon Hua.
This can be helpful for, say, those who have been injured. Exercise on the vibration plate is low-impact and lets them build up their injured muscles or joints, they added.
So far, at least two recent studies have shown that it does lead to increased fat loss.
But there are caveats. Furthermore, no long-term studies on the safety of whole body vibration exercise beyond eight months have been done yet.
BUILDING MUSCLE MASS
Medical and physiotherapy experts interviewed said standing on a vibration plate subjects the body to many small vibrations per second.
This causes the small muscles in the whole body to contract more and the tendons and ligaments to stretch more than when a person is standing on stable ground. This is because the body has to adjust constantly to the motion.
This helps build up muscle mass, strength and flexibility, said the medical experts.
Muscle cells burn more calories than other cells because they are responsible for all movements, including subtle ones such as blinking.
So the increased muscle mass will help the body to burn more calories, leading to the loss of fat.
Dr Daniel Wai, director of the obesity and metabolic unit at Singapore General Hospital, said: “The actual amount of calories burnt after one hour of such exercise (on a vibrating plate) is only around 100calories, but as muscles are built up, it helps increase the amount of energy we burn in the resting state.”
Dr Roger Tian, consultant sports physician and deputy medical director at the Singapore Sports Medicine Centre, said exercising on an unstable platform, such as the vibration plate, increases muscle use as the body tries to maintain stability.
This additional muscle use increases expenditure of calories.
Mr Tay, 39, a former physical education teacher who owns a dedicated Power Plate studio and has shares in Positive Impact, said the machine will increase exercise intensity in two ways.
It helps the body to use more than 90 per cent of its muscles. It also increases the gravitational force by two to six times when a person works out on it. Hence, it will be more difficult for a person to perform exercises on the plate than on the ground.
He said: “As more energy is needed to perform the same exercise, more calories are burnt on the vibrating plate.”
For these reasons, more body fat is lost when whole body vibration training is added to a diet or exercise regimen than either programme on its own or together, two studies have shown.
Both studies – one in Belgium and the other in the United States – were done by doctors and published in peer-reviewed journals.
In the Belgian study on 79 overweight patients published last year, doctors looked at the effect of long-term whole body vibration training on visceral fat.
Visceral fat is the fat surrounding the organs in the abdomen. Abdominal fat is made up of visceral fat and subcutaneous fat, which lies between the skin and the abdominal wall.
The patients were randomly divided into four groups. The first group received a low-calorie diet only, the second dieted and did traditional fitness training, including cardiovascular and weight exercises, the third dieted and followed a progressive Power Plate machine training programme, while the fourth was the control group.
After six months, the group which dieted and followed a Power Plate fitness regimen showed the largest percentage drop in body weight and in visceral fat.
Those in the diet and traditional fitness groups showed a slightly smaller decrease in both measurements, while the control group had no significant change.
In measurements taken at the end of the year-long study, after all participants had returned to their usual lifestyle, the group which exercised on the Power Plate machines was found to have maintained the amount of fat loss. However, the diet and fitness groups had reverted to their initial fat level.
The results were similar in the US study on 55 post-menopausal women, published in 2009. It compared the effects of no exercise, resistance training only and resistance training with whole body vibration.
At the end of eight months, the women who did not exercise gained 1.8 per cent of body fat, while those who did only resistance training lost 1.6 per cent and those who did both types of exercise lost 3 per cent.
RISK OF INTERNAL INJURY
The same effect of burning more calories can be achieved without a vibration plate, said Dr Tian. A person can simply increase the duration or speed of his workout, he said.
Ms Loy Yijun, a senior physiotherapist at National University Hospital’s centre for obesity management and surgery, said whole body vibration therapy alone would probably not lead to weight loss.
Her view is that vibration therapy aims to elicit a similar or superior response to resistance exercises by stimulating muscle reflexes and contractions.
Even if more fat is lost, a person’s cardiovascular fitness may not be significantly improved.
The limitation primarily arises from the lack of a cardiovascular workout, which is essential to burning calories, she said.
Moreover, it is important to realise that vibration plate exercise may result in potential harmful effects, doctors said.
Adjunct Associate Professor Hee Hwan Tak, an orthopaedic surgeon at Singapore Medical Group, said: “This exercise should be done with caution in the elderly or those with balance issues, for fear of falls.”
Soft tissues and body organs could be harmed by long-term vibration. For example, workers using vibration tools such as road drills can suffer from nerve damage to the hands due to chronic vibration. This is called “vibration white finger” disease.
It is not known if long-term use of vibration plate machines will create similar problems.
Dr Wai said: “We do not have studies that last longer than eight months, so do keep in mind that long-term safety is unclear.”
Evaluation of Human Response under
Vibration Condition
Hon Keung Yau, Bing Lam Luk, Sum Sang Chan
Abstract - The purpose of this study is to
investigate the human response under different
vibration frequencies. A total of nine
frequencies (1.6, 2.0, 2.5, 3.15, 4.0, 5.0, 6.3, 8.0
and 10.0Hz) were chosen as stimuli for testing in
the experiment. In this experiment, two tests
were conducted: Comparative Test and Feet Supporting
Test. Ten males and ten females were invited to
participate in the experiment. The major
findings revealed that (i) the uncomfortable
feeling increases with an increase of vibration
frequency, (ii) the feet support does have better
influence to the feeling of comfort for females
than males.
Index Terms – comparative test, human
response, supporting test, vibration
Manuscript received November 15, 2011.
H. K. Yau is with the Department of Systems Engineering and
Engineering Management, City University of Hong Kong, Kowloon
Tong, Kowloon, Hong Kong (corresponding author to provide phone:
852-34426158, Fax: 852-34420173.
B. L. Luk is with the Department of Mechanical and
Biomedical Engineering, City University of Hong Kong,
Kowloon Tong, Kowloon, Hong Kong.
S. S. Chan was with the Department of Mechanical
and Biomedical Engineering, City University of Hong
Kong, Kowloon Tong, Kowloon, Hong Kong .
I. INTRODUCTION
In Hong Kong, most people take the public
transport to various destinations like schools and
offices every day. Common vibrations we can
experience come mainly from the uneven road,
changing of speed, sound produced when a sudden
stop of the bus and train, etc, and these vibrations
can cause damages to us. Different vibrations can
cause different levels of uncomfortable feeling on
males and females. Some past studies have
investigated how vibration affected working
efficiency, safety and health [5]. However, few
studies investigated the gender differences, if any,
in the human response under different vibration
frequencies. Therefore, we fill this research gap in
this study.
II. LITERATURE REVIEW
Vibration interferes with people’s working
efficiency, safety and health [5]. It also causes
discomfort, fatigue and physical pain [3]. Our
health are affected if the strength of vibration is
too large or the duration of vibration is too long
[1]. Past research results showed that feeling of
discomfort increases when the frequency increases
[8]. 5Hz is the resonance frequency for whole-body vibration.
It was also shown that the spine, inner organs and muscle are in
resonance when vibration frequency reaches 8Hz [6], [7]. The
feeling of discomfort increases even higher when more than one
organ of our body are in resonance. The thigh’s stiffness
can only affect little on the feeling of discomfort during vibration [7] while the tensed posture can increase
our stiffness and decrease the feeling of discomfort [4]. In
addition, the posture of tensed upper body
increases the stiffness of body so as to
increase the resonance frequency [2]. Due to
the resonance of spine and inner organs, the
uncomfortable index increases rapidly [6].
Besides, the uncomfortable feeling is much
worse than the relax pose or even cause
damage to our back if the vibration strength
reaches the resonance frequency [3].
III. RESEARCH METHOD
A. Participants
Twenty people (10 males and 10 females)
were invited to participate in the experiment.
They were of average age 21.95 years,
168.1cm tall and 59.1kg weight.
B. Design of experiment
To acquire the data, the following two tests were
conducted:
(i) Comparative test
(ii) Feet supporting test
(i) Comparative Test
Method of magnitude estimation
1. To take the stimulus of 5Hz as a reference
2. Try other stimuli
3. Give an uncomfortable index comparing with the
reference stimulus
(ii)Feet Supporting Test
Method of magnitude estimation
1. Try stimulus without feet support/upper body
relax as a reference stimulus
2. Try the same stimulus with feet support/ upper
body tensed
3. Give uncomfortable index comparing to the
reference stimulus
C. Experiment procedure
For the comparative test, participants were
tested under different vibration frequencies to
analyse discomfort effect at different frequencies.
If the test did not mention about the posture, then
the posture was assumed as upper body relax
without feet support. As many literatures pointed
out that 5Hz was the first starting resonance
frequency, a comparative test referencing at 5Hz
was carried out. Firstly, the participants were
asked to take a stimulus of 5Hz for 4 seconds and a
random selected frequency for another 4 seconds.
After the testing of the two stimuli, participants
were asked to fill in an uncomfortable index survey
as 100 was the mark for 5Hz. For example, if the
participant felt that the selected frequency caused
half uncomfortable feeling compared to that at 5Hz,
then he/she should fill in 50. If they think the
uncomfortable feeling is twice, they should fill in
200. Through the test, we could see whether there
were any differences between the male and
female’s responses at the same vibration level.
For the feet supporting test, participants were
exposed under all vibration frequencies with feet
support for 30 seconds. After that, they were asked
to fill in the uncomfortable index survey.
The test and frequency sequence was
randomized and counterbalanced across trials but
each pair of males and females was under the same
sequence for the analysis of difference in males
and females.
IV. RESULTS AND DISCUSSIONS
(a) Comparative test
Table I: Results of Comparative test
Frequency Index combination
Index male
Index female
1.6Hz 32.25 43 21.5
2.0Hz 39 48 30
2.5Hz 42.75 52 33.5
3.15Hz 62.5 70 55
4Hz 80 82.5 77.5
6.3Hz 117.25 119 115.5
8Hz 144.5 144 145
10Hz 184.5 183 186
From the Table I, the correlation between
uncomfortable index and frequency for male
and female participants are 0.999 and 0.998,
respectively. Feeling of discomfort basically
increased when the frequency increased. This
finding is consistent with the results of Subashi
et al. [8]. Feelings of both males and females were similar
after the resonance frequency 5Hz. The feeling of
discomfort started to increase obviously at 5Hz. That
may be due to the appearance of resonance since 5Hz
which was mentioned by many researchers as the
resonance frequency for whole-body vibration [6], [7]. As
the resonance frequency will make participants feel more
uncomfortable than other frequencies, the feeling may
become similar for both males and females. There is a
large difference for the response of male respondents than
females for all frequencies except 10Hz. Besides, the
difference between males and females in response became
smaller after 5Hz, we can estimate that the vibration
strength may be too large to make both male and female
feel very uncomfortable, so that the response of males and
females are similar after 5Hz. Therefore, it can be
concluded that the resonance made the response in males
and females become similar after 5Hz. At 8Hz and 10Hz,
the uncomfortable feeling increased rapidly, the
uncomfortable index for 10Hz was almost twice of 5Hz.
That may be due to the resonance of our organs. The spine,
inner organs and muscle was in resonance when the
frequency reached 8Hz [6]. If more than one organ of our
body were in resonance, the feeling of discomfort
increased even higher.
(b) Feet Supporting Test
Table II: Results of feet support test
Frequency Index combination
Index male
Index female
1.6Hz 97.5 95 100
2.0Hz 96.5 98 95
2.5Hz 88.5 92 85
3.15Hz 89.25 90 88.5
4Hz 81.5 87 76
5Hz 80.75 84 77.5
6.3Hz 79 84 74
8Hz 72 82 62
10Hz 74.5 88 61
From the results (Table II), we noted that the
feet support does have better influence to the
feeling of comfort for females than males. The
correlation coefficients for males and females are
0.708 and 0.994 respectively. The uncomfortable
index keeps on decreasing when the frequency
increases up to 5Hz for females. This indicates that
the feet support can help to reduce the feeling of
discomfort. We also noted that the uncomfortable
index for females is lower at almost all frequencies
in the condition of using feet support. That may be
due to the difference in strength of buttock for
male and female. Besides, the feet support can decrease
the feeling of discomfort. As mentioned by some
researchers [7], the thigh’s stiffness will affect little
on the feeling of discomfort during vibration. Instead,
tensed posture can increase our stiffness and decrease the
feeling of uncomfortable [4]. Therefore, the difference
in response between male and female becomes
more obvious after 5Hz. Also, the variation of
uncomfortable index at the same frequency is quite
similar for both male and female as shown from the
table 2. The difference in response between males
and females become most significant at 8Hz and
10Hz. The figure shows a significant difference
between male and female at 8Hz and 10Hz. The
uncomfortable index keeps on decreasing but rising
at 10Hz for males, it may be due to the resonance
in organs as mentioned from the comparative test
[6]. But the feet support test is not suitable for all
people as some participants claimed that the feet
support will make them feel more uncomfortable at
some frequencies.
V. CONCLUSION
A series of human factors experiments
concerning the human response under different
vibration conditions was conducted in this study. It
was concluded that the uncomfortable feeling
increased with the increase of vibration frequency.
The difference in response for males and females is
not significant after 5Hz. Also, the feet
support was more useful for females than
males. It seemed that feet support provided
more help to females than males especially at
8Hz and 10Hz. It may be due to the difference
in strength of buttock because the feet support
increased the loading of the buttock.
REFERENCES
[1] C.M. Byung, C.C. Soon and J.P. Se., “Automatic responses
of young passengers contingent to the speed and driving
model of a vehicle,” Int J Ind Ergon Vol. 29, pp. 187-198,
2002.
[2] Y. Huang, and M.J. Griffin, “Effect of voluntary periodic
muscular activity on nonlinearity in the apparent mass of the
seated human body during vertical random whole-body
vibration,” Journal of Sound and Vibration Vol. 298, pp. 824-
840, 2006.
[3] J.Z. Liu, M. Kubo, and H. Aoki, “A study on the difference
of human sensation evaluation to whole body vibration in
sitting and lying postures,” Appl Hum Sci, Vol. 14, pp. 219 –
226, 1995.
[4] Y. Matsumoto, and M.J. Griffin, “Non-linear characteristics
in the dynamic responses of seated subjects exposed to
vertical whole-body vibration,” Journal of Biomechanical
Engineering Vol. 124, pp. 527-532, 2002.
[5] R.W. Mcleod, and M.J. Griffin, “Mechanical vibration
included interference with manual control performance,”
Ergonomics Vol. 38, pp. 1431-1444, 1995.
[6] Mester, Spitzepfeil, and Yue., “Vibration Loads: Potential for
strength and Power development”, 2003
[7] N. Nawayseh and M.J. Griffin, “Non-linear dual-axis
biodynamic response to vertical whole-body vibration,”
Journal of Sound and Vibration Vol. 268, pp. 503–523, 2002.
[8] G.H.M.J. Subashia, and N. Nawaysehb, Y. Matsumotoa, and
M.J. Griffin, (2008). “Nonlinear subjective and dynamic
responses of seated subjects exposed to horizontal wholebody
vibration,” Journal of Sound and Vibration Vol. 321,
pp. 416–434, 2008 .
