Randomized Controlled Trial of a Therapeutic Intervention Consisting of the Use of Whole Body Vibration in Patients With Fibromyalgia.
Phase: NA
Conditions: Fibromyalgia
Sponsor: University of the Balearic Islands

 
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The therapeutic effects of whole body vibration in patients with fibromyalgia. A 
randomized controlled trial.  
Document Date: November 28, 2019. 
Clinical Trial Registration number: NCT03782181. 
Objectives 
To evaluate the efficacy of a 12-week therapy program that involves the use of a whole body 
vibration in patients with fibromyalgia. 
Design 
Single-blind randomized controlled trial. 
Setting 
Fibromyalgia Association in Palma (Balearic Islands). 
Participants 
Patients diagnosed with fibromyalgia according to the criteria of the American College of 
Rheumatology, were recruited from different Fibromyalgia associations in Mallorca (n=40). 
Intervention 
A neuromuscular training with a rotational whole body vibration platform during 12 weeks. 
The control group received no physiotherapy treatment. 
Outcomes 
The following variables were assessed before, after and three months after the therapy 
program: Fibromyalgia impact questionnaire, pain intensity, quality of life, sensitivity 
measurements (pressure pain thresholds, vibration thresholds), motor function tasks (Berg 
scale, six-minute walk test, isometric back muscle strength) and static and dynamic balance. 
Results 
Improvements in the indexes of functional disability, static equilibrium and vibration 
sensitivity were consistent with the reduction of pain sensitivity. 

 
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Conclusions 
The intervention group improved almost all parameters immediately after the therapy 
program, in contrast to the control group that showed no changes. These improvements were 
not maintained in the follow-up. 
Keywords 
Vibration, fibromyalgia, proprioception, postural balance. 
Contribution of paper 
* Fibromyalgia is a chronic pain disease with few effective therapeutic options. 
* Whole body vibration improves pain, somatosensory sensitivity, balance, functional motor 
outcomes and quality of life in patients with fibromyalgia. 
* Continuous use of whole body vibration can be an effective therapeutic option in patients 
with fibromyalgia. 
 
Introduction 
Fibromyalgia (FM) is a chronic syndrome characterized by widespread pain sensitivity, 
fatigue and cognitive symptoms. It affects 3-5% of general population, women 
predominantly [1-3]. It has few effective therapeutic options available. For this reason, it is 
necessary to adopt effective treatments able to reduce its symptomatology. Neuromodulator 
agents, antidepressants or muscle relaxants are the most successful pharmacotherapies in its 
treatment. [4, 5] Some studies have proposed different therapies like individualized 
moderate-intensity exercise [6, 7] or Tai-chi [8] with good results [9] as well as other 
therapies like herbal medications or acupuncture [10-12]. 
 
The whole-body vibration (WBV) has proven to improve health status [13-16], 
strength [17-20], static and dynamic balance [17, 19], physical function [18], pain and 
quality of life [21, 22]. From our knowledge, all the previous studies combined WBV with 

 
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an associated exercise program. Thus, it remains uncertain the active component of the 
therapy leading to the specific effects of WBV [23]. The objective of this randomized 
controlled trial was to compare the effects of a 12-week therapy program consisting in the 
use of WBV with a control group, which did not perform any therapy program. 
 
Methods 
Participants 
The prevalence of fibromyalgia in Spain is 2.4%. The Balearic Islands have about 
20,000 people affected by fibromyalgia, with a 21:1 female/male ratio [24]. A sample size 
calculation was performed using the GRANMO calculator (http://www.imim.es) with a 
confidence interval of 95% and an accuracy of the estimate of 5%. Consequently, we 
recruited forty patients from different associations during December of 2018. The Ethics 
Committee of the Balearic Islands approved the study (IB-2586/15 PI) and it was registered 
at ClinicalTrials.gov (NCT03782181). Randomization was performed in two stages: 
generation of numbers and blind allocation. The envelopes indicated which group the 
participants would be included in were opened after informed consent was obtained. It was 
not possible to blind therapists but the outcome assessors were not informed about the 
allocation of patients in the respective groups. 
All participants met the inclusion criteria: (A) age between 30 and 65 years, and (B) 
diagnosis of fibromyalgia according with the American College of Rheumatology [1]. 
Exclusion criteria were history of severe trauma, peripheral nerve entrapment, inflammatory 
rheumatic diseases and pregnancy. We used a 1:1 allocation ratio and the 40 participants 
were randomly allocated into one of the groups. A single-blinded, 1:1 parallel-group, 
randomized controlled trial was conducted. On the day of admission, a 
physiotherapist informed patients about the study and asked them to participate. A 

 
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randomization list was created by a statistician and administered by a secretary in 
sequentially numbered, sealed envelopes. After baseline testing, the envelope was opened by 
the physiotherapist. 
 
Assessments  
The intervention group performed a program consisted of maintaining 3 different positions 
on the platform during vibration: standing with both feet on the platform for 45 seconds, 
unilateral static position, 22 seconds with each leg. These sessions were held individually in 
the gymnasium of the Fibromyalgia Association in Palma and the entire program was 
supervised by a physiotherapist trained in WBV. Participants in the control group did not 
perform any program. The intervention was performed during the winter of 2019 and the 
follow-up 3 months after the end of the therapy. Two types of platforms can deliver WBV. 
One is a vertical vibration device that induces oscillations over a vertical axis. The second 
one is a rotational vibration device that induces reciprocal displacements on the left and right 
sides of a fulcrum. Some studies using vertical vibration have shown an improvement in the 
anteroposterior stability [17], while studies using rotational vibration showed an 
improvement of the mediolateral stability, more related to the risk of falls [18]. We opted for 
using the rotational vibration and WBV was programmed according with the parameters 
published by previous bibliography [22]: 20 Hz of frequency, and 3 mm of amplitude. 
Assessment of all outcomes in both groups was undertaken at baseline, immediately after the 
therapy and 3 months after the end of the program.  
 
Self-Report Questionnaires  
Fibromyalgia impact questionnaire. This is a validated instrument designed to quantify 
the overall impact of fibromyalgia. We used the Spanish version of the questionnaire [25]. 

 
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Visual analogue pain scale [26]. Each participant was asked to indicate their current 
level of pain using a 20 cm visual analogue scale ranging from 0 to 100. This has been 
reported to be a reliable method for assessing pain [26]. 
Quality of Life Index [27]. This is a self-report questionnaire, previously used to assess 
quality of life in patients with fibromyalgia [28]. We used the Spanish version [27]. 
 
Sensitivity measures  
Pressure pain sensitivity was assessed by means of the measure of pressure pain 
thresholds, expressed in Newtons. This method has demonstrated its reliability to assess pain 
sensitivity [29, 30]. Pressure stimuli were applied on two bilateral body locations: 
epicondyles and index finger. The pressure pain threshold was defined as the pressure value 
considered as painful by the participant.  
Vibration thresholds were evaluated by using a Vibratron (Physitemp Instruments), 
which consists of a controller and two transducers used to determine the intensity of the 
vibratory stimulus perceived by the patient. The testing started with an intensity above the 
threshold, and then it was gradually reduced, asking participants to indicate when the 
vibration was not perceived. Vibration values displayed on the control unit are the amplitude 
of vibration, proportional to the square of applied voltage [31, 32]. 
 
Motor function tasks 
Berg scale. This is a functional assessment tool, consisting of 14 functional tasks. The 
general scores range from 0 to 56. It has been previously used in patients with fibromyalgia 
to assess balance [33]. 
Six-minute walking test. This is a functional test in which the patient walks as far as 
possible during 6 minutes. It has been validated for patients with fibromyalgia [34, 35]. 

 
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Isometric back muscle strength was determined by a dynamometer (T.K.K.5002). 
Participants were asked to pull extending their back, trying to put the body as vertical as 
possible. This test has proven to be reliable in the assessment of back muscle strength [21]. 
 
Static and dynamic balance  
Static balance was assessed by using a modified version of the Romberg’s test [36]. 
Postural control is dependent on input from three peripheral modalities: vision, vestibular 
apparatus and proprioception. Asking the participants to close their eyes during the 
Romberg’s test helps to uncover any disordered proprioception. We analyzed the body sway 
during the test performance. Participants were situated below a webcam (© Logitech) placed 
at a mean distance of 50 cm from the participant’s head. The participant was asked to remain 
in orthostatic position with feet parallels, arms extended along the body and eyes closed for 1 
minute [37]. Velocity and body sway in the anterior-posterior and medial-lateral directions 
were extracted and analyzed by the software CvMob, which produces similar results than 
posturography [38].  
Dynamic balance was assessed by means of a gait task. Participants were instructed to 
walk on a 4 meters carpet. Optical markers were attached at the lateral condyle of the femur, 
great trochanter and lateral malleolus. Subject’s motion was digitally recorded with a video 
camera at 210 frames per second (CasioExilimEX-FS10). The camera was positioned at a 
distance of 4 meters from the carpet. Changes in position and velocity along the x-axis were 
analyzed by CvMob [36, 38]. 
 
 
Statistical analysis 

 
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Analyses were performed using two-way analysis of variance, with the between-factor 
GROUP and the within-subject factor TIME. Effect size was calculated by means of the 
Cohen's d and it was interpreted as small (~0.25), medium (~0.5), or large (>0.8). The 
significance level was set at 0.05. All the analyses were performed using SPSS Statistics. 
 
Results 
The forty subjects enrolled in the groups adhered totally to the program, with no occurrence 
of sample loss. The mean age was 52.5 ± 8.3 years. Most of the participants were female 
(90%). The mean duration of pain was 7.3 years, with an average of 3 years for the clinical 
diagnosis of fibromyalgia.  
Both groups were similar in their sociodemographic characteristics (all p>.05). Table 1 
displays the characteristics of the participants of both groups. Most patients were taking 
analgesics, anxiolytics and antidepressants (Table 2). For medical reasons, medication was 
not discontinued during the study. 
Self-Report Questionnaires  
Fibromyalgia impact questionnaire scores showed a main effect TIME (F (2, 76) =87.47, 
p<.001), showing lower scores in the post-treatment than in the pre-treatment or follow-up 
(both p<.001). An interaction effect GROUP x TIME (F (2, 76) =88.24, p<.001), indicated 
that these effects were produced only in the intervention group.  Post-hoc mean comparisons 
revealed that participants in the intervention group significantly decreased their scores from 
the pre- to the post-treatment (p<.001, Cohen's d=5.22 and effect size of 0.93) but these 
scores increased from the post-treatment to the follow-up (p<.001, Cohen's d =-5.14 and 
effect size of -0.93).  

 
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Visual analogue pain scale showed a significant main effect TIME (F (2, 76) =40.69, 
p<.001) with lower scores in the post-treatment than in the pre-treatment or follow-up (both 
p < 0.001). An interaction effect GROUP x TIME (F(2,76)=41.34, p<.001) indicated that 
only the intervention group reported lower pain scores in the post-treatment and follow-up 
compared to the pre-treatment (both p<.01, Cohen's d > 8.30 and effect size >.97), although 
scores in the follow-up were higher than in the post-treatment (p<.001, Cohen's d =-5.94 and 
effect size of -0.95). Moreover, the intervention group showed higher scores than the control 
group in the pre-treatment (p =.006) but lower scores in the post-treatment (p=.005). No 
differences between groups were found in the follow-up.  
In the Quality of Life Index a significant interaction effect GROUP x TIME F(2, 76)=19.65, 
p<.001) revealed that the intervention group perceived higher quality of life in the post-
treatment than in the pre-treatment (p<.001, Cohen's d =-3.55 and effect size of -0.87), 
although it decreased again between the post-treatment and the follow-up (p<.001, Cohen's d 
=3.67 and effect size of 0.87.). No significant changes were observed in the control group. 
Main effects TIME (F (2, 76) =20.08, p<.001) and GROUP (F (2, 76) =20.08, p<.001) 
showed the same time pattern and indicated higher quality of life in the intervention group 
than in the control (p=.045).  
Sensitivity measures  
For pressure pain thresholds, interaction effects GROUP x TIME in both body locations 
(both F > 38.50, both p<.001) indicated an increasing of thresholds from the pre-treatment to 
the post-treatment (all p<.001, all Cohen's d >-2.45 and effect size >-0.77) only in the 
intervention group. Nevertheless, thresholds decreased again from the post-treatment to the 
follow-up (all p<.001, Cohen's d =2.33 and effect size of 0.76).  

 
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Vibration thresholds showed interaction effects GROUP x TIME in both body 
locations (both F >27.60, both p<.001) indicating a reduction of thresholds from the pre-
treatment to the post-treatment (all p<.001, all Cohen's d >2.92 and effect size >0.82) and an 
increment from the post-treatment to the follow-up (all p<.001, Cohen's d >-2.91 and effect 
size >-0.82) only in the intervention group. In both body locations, thresholds at post-
treatment were lower in the intervention than in the control (both p<.004).  
Motor function tasks 
The Berg scale showed a significant interaction effect GROUP x TIME (F (2, 76) =73.60, 
p<.001). Post-hoc mean comparisons revealed that participants in the intervention group 
significantly improved their scores from the pre- to the post-treatment (p<.001, Cohen’s d =-
7.19 and effect size of -0.96) but these scores decreased from the post-treatment to the 
follow-up (p<.001, Cohen's d =7.17 and effect size of 0.96). Moreover, the intervention 
group showed higher scores than the control group in the post-treatment (p=.001). Main 
effects TIME (F (2, 76) =106.32, p<.001) confirmed this time pattern. 
The Six-minute walking test showed significant effects TIME (F (2, 76) =16.56, p<.001) and 
GROUP x TIME (F (2, 76) =34.87, p<.001). Post-hoc mean comparisons revealed that 
participants in the intervention group significantly improved their scores from the pre- to the 
post-treatment (p<.001, Cohen's d =-4.00 and effect size of -0.89), although these scores 
decreased from the post-treatment to the follow-up (p<.001, Cohen's d =3.76 and effect size 
of 0.88). No significant changes were observed in the control group.  
Isometric back muscle strength also showed significant effects TIME (F (2, 76) =5.95, 
p=.009) and GROUP x TIME (F (2, 76) =13.90, p<.001). Post-hoc mean comparisons 
revealed that participants in the intervention group significantly improved their back muscle 
strength from the pre- to the post-treatment (p<.001, Cohen's d =-2.17 and effect size of -

 
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0.73) but this strength decreased from the post-treatment to the follow-up (p=.001, Cohen's d 
=1.62 and effect size of 0.63).  
Static and dynamic balance  
In static balance, sway in the medial-lateral axis, as well as mean sway velocity showed 
significant effects TIME (all F>5.83, all p<.01) and GROUP x TIME (all F>3.34, all p<.05). 
Again, post-hoc mean comparisons revealed that participants in the intervention group 
increased significantly their mean velocity values and decreased their sway values from the 
pre- to the post-treatment (all p<.001, all Cohen's d >5, all effect size >.78), although these 
improvements were reduced between the post-treatment and the follow-up (all p>.05, 
Cohen's d >-3.5, effect size >-0.87). The intervention group displayed slower and shorter 
sways than the control group only in the post-treatment assessment (all p<.01). No 
significant statistical effects were found in the anteroposterior sway.  
Regarding the dynamic balance, no significant differences were found in any of the 
parameters except gait speed, where a main effect TIME (F(2, 76)=13.88, p<.001) and an 
interaction effect GROUP x TIME (F(2, 76)=3.34, p=.047) revealed again an improvement 
only in the intervention group between the pre- and the post-treatment, and a decline 
between the post-treatment and the follow-up (both p<.001, Cohen's d =-3.28 and 1.37, 
effect size of -0.85 and 0.57, respectively). The intervention group was faster than the 
control group in the post-treatment (p=.008).  
 
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