As there is a growing use for whole body vibrations in physiotherapy, I wanted to help you increase your knowledge and understanding of it as a potential therapy tool for your child.
As professionals we have so far had a bit of healthy scepticism about the advice we give because of the limited research into the benefits and risks. For a while our knowledge of the effects of vibration on the body was limited to some concerning research based on adults who work with vibrating machinery, although we now know that these effects were due to the high frequency of the vibrations. When vibrating platforms were introduced to therapy, a lot of the research available was conducted by the companies selling the machines and could be subject to some bias. Whilst none of the research provides long-term evidence of children using whole body vibrations, there is now a growing body of independent research with some good outcomes for lots of patient groups in the short-term.
We know there are good outcomes for muscle strengthening, flexibility and bone density in children, particularly those with cerebral palsy. However, what we also see is a big variability in outcomes according to foot posture, joint position and support. The evidence is often very generalised and we have to take that into consideration. New research is coming out to suggest that there may be similar benefits for other groups such as osteogenesis imperfecta, spina bifida, muscular dystrophy and spinal muscular atrophy; there is also some slightly tenuous evidence for down syndrome too. All of those have shown early indications of benefit. Most importantly, the research has shown that it is safe at low frequencies.
If you think that whole body vibrations might positively support your child’s therapy then there are definitely some considerations you should make before moving forward.
Vibration plate machines make their movements either vertically or horizontally. Vertical machines move up and down and send vibrations much higher up the body and into the head. I would suggest caution when using this type of machine, especially in children who have growing heads and brains, and might lack head and neck control. These are used more in the fitness industry. Horizontal machines move at both ends around a static central point, like a see saw action. This has a comparatively reduced vibration into the head, yet still has the same benefits for strengthening.
Frequency is measured in hertz (hz) and 1hz is one cycle per second. So the number of hertz refers to the number of times the machine is moving in a second. The amplitude refers to the size of the movement or the strength of the vibrations.
When we combine amplitude and frequency we get the gravitational force or g-force. The concept of whole body vibrations was designed around the body’s reaction to these gravitational forces. If we think about the application of vibration in everyday movement, for example running, each time our feet hit the floor we get an element of vibration through the body and the reaction to that is what is causing our muscles to contract or relax.
The g-force is telling us how hard a muscle is having to work, or whether that muscle is going to be working in a stretched capacity or working to relax and increase circulation. That is determined by the frequency and amplitude and the way those things work together. This is really variable so finding a machine where you can manipulate these settings is really beneficial.
The lower frequencies from 6hz to around 50hz are the ones that will work on our muscle relaxation within safe ranges. However in the paediatric population, particularly children with physical needs, the majority of research indicates that we should be looking at using them within 6hz and 20hz. This would be the most comfortable and manage any potential risks of long-term use of the machines. I am being quite cautious with that suggestion but this area of therapy is still growing in research. The research suggests that over 20hz is typically allowing muscle contractions to happen so probably more for fitness purposes. For the children we are working with we are aiming for strengthening not fitness.
So, when you are making a decision about what settings to use on the machine consider that between 6-10hz you are mainly working on balance, circulation, muscle flexibility and relaxation. Between 10-14hz is ideal for working on the upper body, shoulders and arms. Between 14-20hz you will get the best results for the lower limbs and activation of core stability muscles.
How the machines are used is just as important as getting the frequency correct. It’s important to remember that the advice the company gives about using the machines is generalised; they haven’t been able to assess your child. It would be a good idea to take some examples from machine guidance, a bit of knowledge from this blog or your own research, and then share all that with your physio to come up with a plan to move forward to reduce the risk and make the most of the therapy.
Children’s joint structures need support so posture and positioning are very important, especially when using these machines. Make sure those joints are in good alignment to create the best opportunity for strengthening and reduce the risk of long-term wear and tear.
Also consider what time of day might be best. For example if your child has disturbed sleep due to muscle spasticity then maybe implementing it before bed at a low frequency might help to relax their muscles. Interestingly, a couple of CP patients I work with who use the machines all report that they feel more comfortable, that their muscles feel more stretchy, they feel more relaxed and have less spasticity afterwards.
If you are supporting your child then you will also need to consider your own body. Find something to sit on at the right height to keep them secure. A therapy bench is perfect so that you can adjust the height but a suitable chair or stool will be fine too.
Now that you have a bit of knowledge and information for your toolkit, I hope you will feel empowered to do your own research on whole body vibrations. As a quick recap you will need to consider:
If you would like more information on this topic then head over to my free Facebook group The Parent Platform, where we discuss this and more in our weekly lives. I also offer a membership platform, The Therapy Toolkit Hub™, which is designed to arm you with knowledge, a supportive parent community and a host of information from a highly specialist children’s physiotherapist. I would love to see you in there!