A study into the effects of whole body vibration in MS
Françoise Schyns, Physiotherapist Coordinator
Revive MS Support, Glasgow.
Way Ahead 2010;14(2):10-11
A significant number of people with MS have contacted the MS Trust Information Service with questions about whole body vibration (WBV) machines, which are now available in many gyms in the UK. The MS Trust were therefore delighted to be approached by a research team who also wanted answers to the questions about the safety and usefulness of this therapy for people with MS. In the following article, Françoise Schyns, Physiotherapist Coordinator at Revive MS Support in Glasgow, reports on a pilot study, supported by the MS Trust, investigating the effects of WBV in people with MS.
Despite the fact that there is no published research exploring the effect of WBV combined with exercises for people with MS, more and more people are buying this often expensive equipment. As clinicians, it is important to support and advise patients in their choices of exercises and equipment with the required evidence-based information, especially due to the ever growing, but unverified publicity, made by manufacturers of these vibrating platforms. The purpose of the present study was therefore to establish whether WBV combined with exercises had any effect on some aspects of MS (abnormal tone, muscle weakness, altered sensation and reduced functional performance) and whether those effects were more beneficial to people with MS than exercise alone1.
How does WBV work?
In WBV, the entire body is exposed to vibration as opposed to local vibration where muscles are stimulated by the use of a vibrating device. WBV is implemented through the use of a vibrating platform on which static or dynamic exercises can be performed. The vibrations generated by the engine are transmitted to the person who will stand, sit or lie on the platform. The intensity and the direction of these vibrations depend on the type of machine: different vibration platforms have different vibration characteristics and this is why the results of using them vary2. The vibrations can be produced by vertical displacements of the whole platform or by side alternating movements like a see-saw3. At a physiological level, it is thought that the mechanical stimulation produced by the vibrations generates forces on the body causing muscles to lengthen. This signal, received by muscle spindles, is then relayed to the central nervous system, triggering the stretch reflex. As a result, more motor units are activated and synchronized, producing a larger muscle contraction without additional loading to the passive structures such as bones, ligaments and joints4-5.
Research in healthy participants suggests that WBV has similar effects to resistance training without the side-effects6-9. Some of the reported benefits include:
- increased muscle strength;
- increased bone density;
- increased hormonal responses;
- improved blood circulation; and
- improved flexibility.
It has also been claimed that WBV could offer a therapeutic alternative for people with limited physical abilitiy10. Indeed, several research studies investigating the use of WBV in the rehabilitation of people with neurological conditions have shown some promising results11-14.
16 people with MS took part in the study; 12 females and 4 males. Study participants received a programme of exercises with and without vibrations over a three month period. An experimental within subject cross-over design was used. To be eligible to participate in the study, the participants had to have:
- a confirmed diagnosis of MS;
- a disability level 1-6 measured by the Hauser Ambulation Index; and
- at least one of the following symptoms of the lower limbs: abnormal muscle tone, lower limb weakness, and altered sensation and/or proprioception.
The main contraindications of WBV include pregnancy, cancer/tumour, pacemaker, plate/screws/pins, epilepsy, thrombotic conditions and uncontrolled diabetes. MS relapse, infection or severe dizziness were added to the list of contraindications to define the exclusion criteria.
For the present study a vibrating machine called Vibrogym which produced vertical vibrations was used. The parameters we chose for the study were guided by the manufacturer's recommendations.
The Vibrogym offers the following choice of settings:
- vibration frequency: between 30-50Hz;
- vibration amplitude (vertical displacement): 2 or 4mm;
- duration of exercise: 30, 45, 60 seconds.
Different parameters are recommended for massage, strengthening and stretching exercises. Any exercise programme should progress from static positions to dynamic exercises.
In the study, the participants were randomly allocated to two groups. Each protocol was performed three times per week, for four weeks, followed by a two week rest period.
In Group 1, eight participants received protocol A followed by protocol B. In Group 2, eight participants received protocol B followed by protocol A.
The exercise programme consisted of a warm up, a cool down, and a series of exercises (mostly isometric) for lower limbs, all done on the vibrating platform with vibrations set at a frequency of 50Hz (the massage mode for warm up and cool down) and 40Hz (for exercises), and at a low amplitude (2mm). Each exercise was performed for 30 seconds. The warm up/cool down exercises were performed for 60 seconds for three different muscle groups (calves, hamstrings and quadriceps).
The exercise programme consisted of the same series of exercises for lower limbs but was performed on the vibrating platform without vibrations. Study participants were led to believe that the vibrations were on but their settings were such that they could not be felt nor heard. Each exercise was also carried out for 30 seconds, and the warm up/cool down consisted of three minutes on a static cycle using passive mode.
Different outcome measures were taken by a blind assessor before and after each four week exercise period and the rest period:
- Tone - Modified Ashworth Scale (MAS) and the Multiple Sclerosis Spasticity Scale - MSSS-88
- Strength of lower limb - Dynamometry (HHD) for hip flexors and extensors, hip adductors and abductors, quadriceps, hamstrings and ankle dorsi-flexors
- Sensation of lower limbs (distal) - Nottingham Sensory Assessment (NSA)
- Function - 10 metre walk and 'Timed up and go' (TUG)
- Wellbeing - Multiple Sclerosis Impact Scale - MSIS-29
- General experience - Subjective comments
12 people completed the study: five of these had bilateral symptoms and seven presented with symptoms only in one of their lower limbs.
There was insignificant evidence to suggest that the order in which protocols A and B were followed made any difference to any of the outcome measures so the effect of WBV and exercise was compared with that of exercise alone regardless of the order of the interventions.
Most of the scores on the MAS remained unchanged following each of the interventions. With regards to muscle spasm and pain scores (subscales of the MSSS-88), there was a statistically significant change in the results implying a reduction of these two symptoms after WBV with exercise.
For muscle strength, the results suggested that for the seven muscle groups tested (hip flexors and extensors, hip abductors and adductors, quadriceps, hamstrings and ankle dorsi-flexors) there was a trend towards an improvement, especially following WBV and exercise. However, this difference did not reach statistical significance.
Surprisingly, for most subjects, the results showed that neither of the interventions had an effect on sensation: the scores did not change for the five sensations measured with the NSA (light touch, pin-prick, temperature, pressure and proprioception).
For the two functional measures, the 10 metre walk and TUG, both interventions had a positive effect, ie an increase in the participant's walking speed and a reduced timed up and go. However, the difference between WBV with exercises and exercises alone did not reach statistical significance for either of the outcome measures.
Subjects' well being was improved by both interventions, but there was no evidence that WBV added any value to the exercises.
It is worth noting that although WBV did not produce strong evidence for improvement in most of the outcome measures, subjective comments from patients were generally positive for both interventions. Participants reported improved sleep, increased levels of energy and better mood. Interestingly, additional benefits were reported after the use of vibration with exercises: reduction in leg cramp, enhanced feeling of the ground and improved ability to negotiate stairs.
In summary, the results of our study suggest that exercises performed three times a week for four weeks helped to improve muscle strength, functional ability and general wellbeing. While exercises are beneficial to people with MS, our study demonstrated limited evidence that including WBV provides any additional improvements. However, there is evidence that WBV combined with exercises provided more benefit than exercise alone in reducing muscle spasms and related pain. There was also a trend towards a greater increase in muscle strength with the addition of WBV. Exercise, with or without WBV, appeared to have had no effect on sensation or muscle tone. Throughout the course of the study, none of the subjects reported any significant deterioration in symptoms. On the contrary, participants reported a number of perceived positive benefits especially after the use of vibration.
WBV did not appear to have any adverse effect on MS symptoms and thus may be used in a therapeutic programme. It is important to stress that this was a small pilot study and that further research involving larger numbers of people are necessary to clarify the effects of WBV on MS symptoms.
A number of useful pointers derived from further clinical experience, observation and practice are also worth noting:
- anyone with MS considering trying WBV should first consult a physiotherapist who will assess the individual's symptoms and recommend the type of exercises needed (strengthening, stretching, etc);
- discussion about using WBV training is vital as the physiotherapist will be able to investigate the suitability of this method;
- special consideration should be given to the contraindications of vibration therapy. The contraindications are usually listed by the manufacturer; the frequency and the direction of the vibrations may vary between different vibrating machines. Before using a platform, individuals should determine which type of vibrations it delivers and the set up parameters it has;
- the dosage, intensity and progression of exercise depend on an individual's level of fatigue and general fitness. Nevertheless, regular exercises are needed to see any benefit;
- individuals with a more unilateral presentation seem to have greater benefit, especially in terms of balance. Often, people report benefits in such terms as: 'ease of movement', 'movements more fluid', 'light feeling in the limbs', 'feel more grounded';
- monitoring the effects of WBV is crucial and the assistance of a physiotherapist will help identify any benefits or side effects of the therapy.
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