In a recent study completed in China and published in Aging Clinical and Experimental Research, it was demonstrated that Whole Body Vibration (WBV) training on a pivotal (a.k.a. “alternating” or “side to side”) platform led to a significant increase in bone mineral density (BMD) at both the lumbar spine and the hips. These two areas, along with the wrists, represent the most prevalent areas for declining BMD in both males and females. Even further, the positive results of this study were found for both sexes regardless of whether they were diagnosed with osteopenia or osteoporosis. This study is now one of over 12 studies recently conducted internationally that has demonstrated the efficacy of WBV training for the purposes of reducing the loss of or increasing bone density in individuals.
With osteoporosis affecting a growing number of people over 50 years of age (In the US, 8 million woman and 2 million men are estimated to have it), new thoughts and treatment options are in great need. Our primary intervention to date has been pharmaceuticals, which to no great surprise, has not only been ineffective for many people, but has shown to have a number of serious side effects.
Outside of pharmaceutical approach, the most prevalent “natural” intervention has come in the form of generic recommendations to perform “weightbearing resistance exercises”. Although this recommendation can be effective, most recommended programs are prescribed with little understanding of what is required to trigger an adaptive response at the level of the bone. This has resulted in improper training programs which not only have little effect on bone, but further allow the age-related reduction in lean muscle mass (referred to as sarcopenia) to occur. For those fortunate individuals that are prescribed an appropriate weightbearing program, the repeated participation is this type of program comes with great risks. Among these risks include muscle and tendon overuse injuries, compressive joint irritation (especially in those with pre-existing osteoarthritis), and low back pain. This can be corrected to some extent with proper instruction on form and execution, but this appears to only reduce the risk as opposed to eliminate it. Other than that, and perhaps the biggest limiting factor is that these programs typically require 45-60 minutes of dedicated training time, which is approximately 45-60 minutes more than most people are willing to give to exercise.
WBV training on the other hand, a form of resistance training, represents an exciting and promising treatment option due to the fact that it resolves most of these limitations. Not only does it provide the necessary forces required for adaptation, but seemingly appears to be of very low impact on the joints and surrounding tissues. Furthermore, WBV training, based upon the research, requires no more than 10-20 minutes of training time. Given this information, it is time to stop searching for a “magic bullet” and start seeking out this new tool in the fight against this epidemic.
How it Works
How WBV training influences bone density is a source of some dispute, but the growing amount of research utilizing the mechanostat theory, a theory describing the relationship between muscle and bone is emerging as the leading candidate. Roughly put, this theory states that bone growth and bone loss is stimulated by the local mechanical elastic deformation of bone. The reason for the elastic deformation of bone is the peak forces caused by the contractions of the surrounding muscles.
WBV training involves the manipulation of the variables of amplitude and frequency. These two parameters, varying from one machine to the next, combine to determine the acceleration of the platform (described as the platform’s “G-Force”). Since the users mass (bodyweight) is constant and we have a given acceleration, we can determine the force (F=MxA) that the user’s muscles must respond to. Therefore, by manipulating these variables, we are able to increase the peak force that must be generated in the muscles. Through increases in force generation, based upon mechanostat, we are able to exert greater strain on the bone and can therefore expect a corresponding increase in bone mineral density.
Other ideas have been proposed, including piezoelectricity and cellular responses due to the repeated transmission of forces (through compression) on the joints by the platforms repeated movement. When considered together however, these theories, along with several others, may just represent various theories describing the same mechanisms; the only exception being which part of the collective process in considered the “driver”. Unfortunately, the complexity of the neuromusculoskeletal system will likely make it quite difficult to ever establish a “final answer”. In the meantime, the research clearly points to one thing, Whole Body Vibration Training should not be overlooked! For this reason it is time to make an effort to move “beyond the shake” and better understand the intricacies of WBV training. Through further education, we can start to combat osteoporosis and improve the lives of the many people dealing with this deleterious process.
Gabriel Ettenson, PT is a physical therapist in New York, NY. He is the owner of Equilibrium Physical Therapy and Amplitude Vibration Studio.