In order to appreciate the benefits vibration exercise therapy can have on your patients, it’s important to know the underlying mechanism behind how it works. Today, we’ll discuss the science behind vibration exercise, thereby getting a better appreciation of the physiological effects that it will have on your patients.
Biomechanical Muscle Stimulation
Vibration exercise can come in many forms, from hand held devices to large platforms. I think it’s a bit of a misnomer calling it ‘vibration’. A better analogy would be that of Electrical Muscle Stimulation. With EMS, the goal is to create muscle contractions involuntarily. However, you are limited to the muscles that are directly associated with the motor units that are in contact with the stimulation pads. In addition, this is a passive form of therapy. If we called vibration exercise ‘Biomechanical Muscle Stimulation’, then it would be a bit clearer to most clinicians on what it does. Vibration exercise therapy is more of an active form of therapy, allowing an individual to progress in various exercise positions from static to dynamic.
The Tonic Vibration Stretch Reflex:
Vibration exercise basically works through the stretch reflex. This is the same stretch reflex that is initiated when we tap a patient over the knee with a reflex hammer. There is a strong involuntary contraction that occurs, leading to contraction of the quadriceps muscle. We all remember doing this over and over again in first year class on diagnostic testing. The vibration platform works in the same way. Take for example, someone being placed in a squat position on a vibration platform. The platform will drop a few mm, leading to a quick stretch of the muscles. As a response, there will be a strong involuntary muscle contraction that occurs in the quadriceps muscle. Now consider that the platform can drop up and down 50 times per second. That leads to 50 muscle contractions per second, and up to 3000 contractions within 1 minute. Since it is involuntary, a lot of patients that are unable to engage in conventional strength training exercises can now have an option that will allow their muscles to get the work load it requires.
Neurological Adaptation:
I’ve always had people ask how it’s possible to gain strength when all a person does is stand on a platform in a static position for as little as 2 minutes total vibration time. It almost comes across as an ideal pitch on a late night infomercial! However, let’s take a look at how strength gains are achieved with conventional training first. Everyone that has taken time off from weight training and then begins again, will notice something startling within the first 4 to 6 weeks of training. Every day you go to the gym, you are pleasantly surprised on how much you can increase your lifting capacity. It seems like you’ll be able to lift 500 pounds in no time. However, after the initial exhilaration, we all tend to plateau. This first blast of increased strength does not come from increasing the size of our muscle fibres through hypertrophy. This basically comes from increasing the amount of muscles that are recruited for that particular exercise. This is called neurological adaptation. However, we tend to plateau and then have to rely on increasing strength through hypertrophy. Vibration exercise therapy is based on increasing strength through neurological adaptation. Since the muscle contractions are involuntary, a greater number of muscle fibres are recruited than with conventional training. There is a great advantage to this. In a rehabilitation setting, we aren’t trying to make someone super human or work towards becoming Mr. Universe. Our goal is to increase strength and stabilize joints as quickly as possible. With vibration exercise, you’ll be able to make those initial strength gains quicker, thereby progressing the patient faster through their rehabilitation stages.
Force = Mass X Acceleration:
Anyone that weight trains knows that in order to increase strength, one has to consistently continue to increase the amount of weight they are lifting in order to see strength gains and muscle hypertrophy. Therefore, the FORCE generated is based upon increasing the MASS of the object one is lifting.
As we already can see, vibration exercise is based upon the acceleration of the platform, dropping up and down a certain number of times at a certain distance. Therefore, vibration exercise increases the force on the muscles through the ACCELERATION of the platform instead. However, add resistance bands, hand weights, or weighted vests to your patients, and you‘ll get added benefit from the increase in mass also.
In essence, this should give you a simplified explanation of the mechanisms behind vibration exercise therapy. Once these are known, it’s easier to understand the many benefits that are achieved when applying it to your patient population.