ORIGINAL ARTICLE
Effect of whole-body vibration exercise and muscle strengthening,balance, and walking exercises on walking ability in the elderly
Kazuhiro Kawanabe,1 Akira Kawashima,1 Issei Sashimoto,1 Tsuyoshi Takeda,2 Yoshihiro Sato, 3
and Jun Iwamoto 2
1

Kawashima Orthopaedic Clinic, Chiba, 2 Department of Sports Medicine, School of Medicine,
Keio University, Tokyo, 3 Department of Neurology, Mitate Hospital, Fukuoka, Japan(Received for publication on September 25, 2006)(Revised for publication on January 11, 2007)(Accepted for publication on January 25, 2007)

Abstract. The present study was conducted to determine the beneficial effect of wholebody vibration (WBV) exercise in addition to muscle strengthening, balance, and walking
exercises on the walking ability in the elderly. Sixty-seven elderly participants were divided
into two groups; the WBV exercise plus routine exercises group (n=40) and the routine exercises alone group (n=27). WBV exercise was performed on a Galileo machine (Novotec,
Pforzheim, Germany) at an intensity of 12―20 Hz, for a duration of 4 minutes, once every
week. All the participants in both the groups were similarly instructed to undergo routine
exercises such as balance and muscle strengthening trainings, and take walking exercise
twice a week. The period of this study was 2 months to evaluate the acute effects of WBVexercise. The mean age of the participants was 72.0 years (range, 59―86 years). At baseline, there were significant negative correlations between age and the walking speed, step
length, and maximum standing time on one leg. After the 2-month exercise program, thewalking speed, step length, and the maximum standing time on one leg were significantly
improved in the WBV exercise plus routine exercises group, while no significant changes
in these parameters were observed in the routine exercises alone group. Thus, the present
study showed the beneficial effect of WBV exercise in addition to muscle strengthening, balance, and walking exercises in improving the walking ability in the elderly. WBV exercise
was safe and well tolerated in the elderly. (Keio J Med 56 (1) : 28 －33, March 2007)
Key words: elderly, fall, muscle power, body balance, walking ability

Introductionsociated with them would reduce disability, improve thequality of life, and reduce the costs of health care.
Exercise is generally accepted to be effective for theprevention of falls in the elderly. A meta-analytic study
has demonstrated that exercise is effective for lowering
the risk of falls in the elderly and that the consequent
reduction in the incidence of fall-related injuries reduces health care costs; however, there is little available
information on the costs associated with the program
replication, that is, the cost-effectiveness of the exercise
programs aimed at preventing falls.3 With respect to exercise programs that appear to be effective for the abovementioned purposes, a systematic review has demon-

Impairment of muscle strength and power of the lower
extremities, balance/postural control, and of the walking
ability have been found to be important risk factors forfalls.1 These parameters are known to become progressively more impaired with aging, and the age-related decrease in the muscle strength and power are known to bemuch more marked in the lower extremities than in theupper extremities.2 Fall-related injuries, including head
injuries and fractures, are serious problems in the elderly,
as they often lead to prolonged/permanent disability.
Thus, prevention of falls and therefore, of the injuries as-

Reprint requests to: Dr. Jun Iwamoto, Department of Sports Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo
160-8582, Japan, E-mail: jiwamoto@sc.itc.keio.ac.jp28

Keio J Med 2007; 56 (1): 28－33

strated that muscle strengthening and balance exercises
and Tai Chi are effective for preventing fractures in theelderly; the respective relative risk reduction rates forfalls with the two exercise programs have been reported
to be 20% and 51%4; thus, Tai Chi is probably the mosteffective for decreasing the risk of falls.4-6
Recently, whole-body vibration (WBV) exercise has
been developed as a new modality in the field of physiotherapy. It has been suggested that WBV exercise
increases muscle power and strength and improves muscular performance and body balance.7, 8 These effects
of WBV exercise have been recognized immediately
after the exercise,7, 8 and seem to be more marked in elite
athletes than in non-elite athletes.9 Thus, WBV exercise
may be more effective in subjects with higher neuromuscular performance, and its efficacy still remains tobe well established in the elderly. We have previously
reported that 3-month WBV exercise combined withbalance (standing on one leg) and muscle strengthening(half-squat) exercises improved the step length, knee extensor muscle strength, and maximum standing time on
one leg in elderly women.10 However, this study had nocontrol group, and the effects on walking ability were notdistinguished between WBV exercise and balance andmuscle strengthening exercises. The present study was
conducted to determine the beneficial effect of wholebody vibration (WBV) exercise in addition to muscle
strengthening, balance, and walking exercises on thewalking ability in the elderly.
Methods
Sixty-seven patients (4 men and 63 postmenopausal
women) who visited our clinic (Kawashima Orthopaedic
Clinic, Chiba, Japan) between April 2005 and May 2006
were recruited to our trial. The physical activity level atbaseline was considered to be low in all of the participants, because none of them were laborers or had been
engaged in any sporting activities. They were divided
into two groups; the WBV plus routine exercises group(n=40) and the routine exercises alone group (n=27),
according to their intention to perform WBV exercise.
WBV exercise was performed on a Galileo machine (Novotec, Pforzheim, Germany), at an intensity of 12―20 Hz,
for a duration of 4 minutes, once every week. The Galileo machine is a unique device for applying whole-bodyvibration/oscillatory muscle stimulation. The subject
stands with bent knees and hips on a rocking platform
with a sagittal axle, which alternately thrusts the rightand left legs upwards and downwards, thereby promoting lengthening of the extensor muscles of the lower
extremities. The reaction of the neuromuscular system isa chain of rapid muscle contractions. This type of training provides reflex muscle stimulation with no serious
adverse events. All participants in the both groups were29

similarly instructed to undergo routine exercises suchas balance (standing on one leg and tandem gait) andmuscle (the calf, quadriceps, hamstrings, and gluteus medius) strengthening trainings and take a walking exercise(30 minutes) twice a week. The period of this study was
2 months to evaluate the acute effect of WBV exercise
in addition to routine exercises on the walking ability inthe elderly. Informed consent was obtained from each of
the subjects prior to their participation in the study. The
study was carried out at Kawashima Orthopaedic Clinic,
and the protocol was approved by the Ethical Committeeof Kawashima Orthopaedic Clinic.
The data are presented as means ± standard error (SE).
Data comparison between two groups was performed byunpaired t-test. Correlations between the age and tenmeter walking time, step length, and maximum standingtime on one leg were examined by simple linear regression analysis. The longitudinal changes in the parameters
were evaluated by one-way analysis of variance (ANOVA) with repeated measures. All statistical analyses
were performed using the Stat View J-5.0 program (SASInstitute, Cary, NC, USA). The significance level was set
at P<0.05 for all the comparisons.
Results
Characteristics of the study subjects
Table 1 shows the baseline characteristics of the study
subjects. The mean age of the participants was 72.0 years(range, 59―86 years). There were no significant differences in any of the baseline characteristics between the
WBV exercise plus routine exercises group and the routine exercises alone group.

Table 1 Characteristics of the study subjects
WBV+Routine Ex Routine Ex
P values(n=40)(n=27)(Unpaired t-test)
Age (year)

71.8±0.972.3±1.4

Male /Female

1/39

3/24

10-m walking time (sec)

9.0±0.7

7.3±0.50.1001

Step length (cm)61.2±1.765.8±2.1

0.102718.7±6.6
19.6±7.6

0.93720.6714

Maximum standing time on one leg (sec)18.3±2.7
Right side
16.7±2.9
Left side

0.7491

Data are expressed as means ± standard error (SE). WBV: whole-bodyvibration, Ex: exercises. There were no significant differences in age,
10-m walking time, and maximum standing time on one leg between
the two groups (unpaired t-test).

30

Kawanabe K, et al: Effect of exercise in the elderlyFig. 1 Correlation between age and the walking ability.
Simple linear regression analysis was used to examine the correlation between age and the walking ability. There was a significant
positive correlation between age and the 10-m walking time. There were also significant negative correlations between age and the step
length and maximum standing time on one leg.

Correlation between age and the walking ability
Fig 1 shows the correlation between age and the walking ability. There was a significant positive correlation
between age and the ten-meter walking time (R2=0.056,
P<0.05). There were also significant negative correlations between age and the step length (R2=0.212,
P<0.001) and maximum standing time on one leg (rightleg, R2=0.080, P<0.05; left leg, R2=0.170, P<0.001).
Effect of WBV exercise on the walking ability
Fig 2 shows the effect of WBV exercise in addition to
routine exercises on the walking ability in the subjects.
Although the values of ten-meter walking time and step

length seem to differ between the two groups because
the data are expressed as means ± SE, the differenceswere not statistically significant as shown in Table 1.
After the 2- month program, the ten-meter walking time,
step length, and maximum standing time on one leg
were significantly improved in the WBV exercise plus
routine exercises group, while these parameters did notchange significantly in the routine exercises alone group.
The percent changes in the ten-meter walking time, step
length, and maximum standing time on one leg for theright and left side following WBV exercise plus routine
exercises were -14.9%, +6.5%, +65.0% (right side) and+88.4% (left side), respectively. During the study period,
no serious adverse events, such as fall-related injuries oradverse cardiovascular effects were observed.

Keio J Med 2007; 56 (1): 28－33

31

Fig. 2 Effect of WVB exercise on the walking ability.
The data are presented as means ± standard error (SE). Although the values of 10-m walking time and step length seem to differ
between the two groups, the differences were not statistically significant as shown in Table 1 (unpaired t-test). One-way analysis ofvariance (ANOVA) with repeated measurements was used to examine the longitudinal changes in the parameters. After the 2- monthprogram, the 10-m walking time, step length, and maximum standing time on one leg were significantly improved in the WBV exercisegroup, while these parameters did not change significantly in the control group. * P<0.05. WBV: whole-body vibration, Ex: exercises.

Discussion
The present study confirmed the existence of agerelated impairment of the walking ability, including
the walking speed, step length, and maximum standingtime on one leg in the elderly. Muscle strength should
be distinguished from muscle power; muscle strength isdefined as the force or tension that the muscle can exert
against a resistance, while muscle power is defined as
the speed of movement or the rate at which a resistancecan be moved per unit of time. Because walking speed
could be considered as one of the indices of muscle power and maximum standing time on one leg as one of theindices of body balance, our results suggest the existenceof age-related impairment of muscle power, step length,and body balance.
A consensus has been reached with respect to exercise programs for the elderly; that is, a combination ofmuscle strengthening exercises of the back and lower
extremities, balance exercises, and walking may be effective to prevent vertebral and non-vertebral fractures.11
However, our routine exercises alone did not improve
the walking speed (an index of muscle power), step
length, and maximum standing time on one leg (an index
of body balance), suggesting short-term routine exercises such as muscle strengthening, balance, and walking exercises were not always effective for significantly
improving the walking ability in the elderly. Although
this kind of exercise program is popularly performed forthe elderly in many countries, physicians should confirm
the efficacy of their own exercise programs and then put

32them in practice.
However, WBV exercise plus routine exercises significantly improved the walking speed (an index of muscle
power), step length, and maximum standing time on one
leg (an index of body balance) in the present study, suggesting the beneficial effect of WBV exercise in addition
to routine exercises in improving the walking ability.
Numerous studies have confirmed the beneficial effects
of WBV exercise on the musculoskeletal system. It has
been shown to improve the knee extensor strength, vertical jump height (jumping power), chair-rising time,
timed up & go, body balance, chronic back pain, and hipbone mineral density, and also to increase the serum levels of testosterone and growth hormone.1, 7-10, 12-18 Vertical jumping height, chair-rising time, and timed up & go
are considered possibly to be indices of muscle power.
On the other hand, our routine exercises were performed
aiming at improving muscle strength, body balance, andwalking speed (an index of muscle power) in the elderly,
although we did not obtain any significant neuromuscular effect of routine exercise alone. The present study
showed the short-term beneficial effect of WBV exercise
plus routine exercises on a muscle power index in termsof the walking speed, as well as the body balance in theelderly. WBV exercise was well tolerated and no serious
adverse events, such as fall-related injuries or adverse
cardiovascular effects were observed in any of the subjects during the WBV exercise program.
WBV exercise plus routine exercises also increased
the step length, however the reason for this remains uncertain. Basically, each stride during walking consists ofthe stance and swing phases. Thus, increased maximum
standing time on one leg can produce more stable walking. That is, the more the stance phase of each leg wasstabilized by the WBV exercise plus routine exercises,
the greater the swing of the other leg becomes, resulting
in an increase in the step length. Because impaired walking ability is associated with decreased step length, 1 9
increased step length may also indicate improved thewalking ability. Because it is important for the elderly toincrease the step length to touch the ground with the heel
during walking in order to prevent falls caused by stumbling of toes, we believe that improvement of the step
length could also lead to a reduction in the fall risk.
The efficacy of WBV exercise plus routine exercises
for walking ability might result from either the effect of
WBV exercise itself or the combined effect of two exercises. WBV has been reported to have both beneficial
acute and chronic training effects on muscle strength andpower enhancement.9 However, the mechanism underlying the acute effects of WBV exercise on the musculoskeletal system remains uncertain. WBV has been shownto elicit acute hormonal profile and neuromuscular performance responses immediately after the exercise.8 It
has also been reported that low-intensity resistance exer-

Kawanabe K, et al: Effect of exercise in the elderly

cise with vascular occlusion rapidly increases the serum
levels of growth hormone, suggesting that certain kindsof exercise may rapidly stimulate the secretion of growth
hormone.2 0 Thus, one of the possible mechanisms for
explaining the acute beneficial effect of WBV exercise
plus routine exercises on the musculoskeletal system isthe rapid stimulation of growth hormone secretion after
WBV exercise, because it has been reported that WBV
exercise is associated with increased serum levels of
growth hormone and testosterone which have anabolic
actions on the muscle, immediately after the exercise.8
Further studies are needed to confirm this contention.
We applied WBV exercise, at an intensity of 12―20
Hz, for a duration of 4 minutes, once every week, for
two months. The intensity was set according to individual ability to undergo the WBV exercise. However,
the intensity and frequency might be low and the duration might be short, because this exercise program was
simply conducted to determine if the elderly could safely
undergo and easily continue the exercise. Therefore, one
criticism is that it remains uncertain whether the dose of
WBV exercise might be enough to observe an improvement of the walking ability in the present study. Thus,
another possible mechanism for explaining the efficacy of WBV exercise plus routine exercises may be that
WBV exercise might enhance the effect of routine exercises on the walking ability in the elderly, even if WBVexercise itself did not significantly affect the walking
ability.
The limitations of this study should be discussed. First,
the study period might have been too short and the ageof the subjects too low to arrive at any reasonable conclusion of the beneficial effect of WBV exercise plus
routine exercises on the incidence of falls. Flexibility,
body balance, and muscle power and strength are important factors that must be considered while evaluating
the risk of falls in the elderly.1 Thus, further studies onolder subjects with a longer study period are needed todefinitively determine the efficacy of WBV exercise on
a Galileo machine in addition to routine exercises on allof these parameters and the incidence of falls and fallrelated injuries. Second, this study is not a randomized
controlled trial and the choice to have WBV exercise
was decided by the patients themselves. Therefore, themotivation to improve the walking ability might havediffered between the two groups, and the difference insuch attitude to comply the program might have affected
the results. Further randomized controlled studies areneeded to confirm the results of the present study.
In conclusion, the present study showed the beneficial
effect of WBV exercise in addition to muscle strengthening, balance, and walking exercises in improving thewalking ability in the elderly. WBV exercise was safe
and well tolerated in the elderly.

Keio J Med 2007; 56 (1): 28－33

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