October 2006, Vol. 16, No. 4
The medicinal use of vibration is not new. Vibration as a medical technique was mentioned in ancient Greco-Roman sources and vibratory massage was popular among physicians in the 19th century.1 The use of mechanical vibration for strength training purposes began attracting interest less than two decades ago.1 Russia Olympic trainers are usually credited with the development of whole body vibration during the 1970’s when the Russians were dominating Olympic play. Success with the athletes led to research by the Russian space program to use whole body vibration to prevent excessive bone loss in astronauts while they are up in space.2
Vibration is an oscillatory motion. The extent of this motion determines the magnitude and amplitude of the vibration and the repetition rate of the cycles of oscillation determines the frequency of the vibration (measured in Hz). Vibration can be locally applied by means of vibrating support rolls or cushions, or with vibrating dumbbells or cables, or applied to the whole body by means of a vibrating platform. During whole body vibration, the transmissibility and impedance response of the human spine show increases at their resonant frequency.3 This means that the greatest motion throughout the spine, and therefore the greatest effect (either beneficial or detrimental) would be achieved at resonant frequency.
The damaging effects of long duration whole body vibration have been extensively researched. There is an association between jobs that expose the individual to long duration, low-frequency whole body vibration, such as tractor, truck and bus drivers and:
- Increased lumbar spinal degeneration4
- Increased incidence of low back pain4
- Erector spinae muscular fatigue4,6
On the other hand, recent work has suggested that low frequency, short duration mechanical stimulation of the human body is a safe and effective way to exercise and strengthen musculoskeletal structures, improve sensory-motor neural pathways, improve proprioception/posture and decrease chronic low back pain.1,4,5,6 Also, because of its ability to relax musculoligamentous structures and enhance flexibility,1 low amplitude, low frequency whole body vibration may enhance their remodeling during postural/structural corrective traction and make the whole traction process more physically tolerable for the patient. This would theoretically allow the patient to perform traction with higher traction loads for longer periods of time, thus improving results. I will elaborate on the positive effects of short duration, low frequency whole body vibration as well as provide a short case study to demonstrate its clinical abilities.
POSITIVE PHYSICAL EFFECTS OF WHOLE BODY VIBRATION
“The body relies on a range of structures and mechanisms to regulate the transmission of impact shocks and vibrations through the body including: bone, cartilage, synovial fluids, soft tissues, joint kinematics, and muscular activity.”6
The amplitude of the vibrations will be greatest if the natural frequency of the involved tissues is close to that of the input force (resonance), however, the amplitude can be reduced by damping from the tissues.6 When the body undergoes vibration, muscle activity is necessary for damping the vibratory waves.4 This has been defined as muscle tuning via the “tonic vibration reflex.”4 Muscle tension linearly increases with the frequency of vibration.1 In most studies involving vibratory stimulation during strength exercises, a frequency range form 20-45 Hz is used because low frequency vibration propagates well through contracted or stretched muscles and higher frequency vibration is absorbed by the soft body tissues.1 The exercise is usually preformed in a dynamic fashion (ex; squats with and without additional load) in less than one minute and then the patient gets off the vibratory platform. Prolonged vibration (1 minute or more) reduced the firing rate of motor units and motor output and has a suppressive effect.1 Prolonged vibration also causes as much as a 200 percent increase of blood flow to the muscles involved evoking a thermal effect that also enhances flexibility.4 So while the physical effects of prolonged vibration may be very beneficial in 10-20 minute intervals for postural/structural corrective traction procedures, it is usually not recommended for strength training exercises in intervals over one minute. Notable strength gains (especially with jumping performance) that were superior to gains achieved with non-vibratory resistance training was recorded in most studies, especially with middle aged and older individuals.1,6 Stretching exercises are also enhanced if done on a vibrating platform. Not only because of the increased blood flow already mentioned, but because vibration appears to inhibit activation of antagonist muscles,4 improve neuromuscular coordination and produce a pronounced analgesic effect.1
Whole body vibration exercise has also been shown to:
- Be effective in reducing pain sensation and pain-related disability in patients affected by chronic low back pain.7
- Improve balance/posture, even when the displacement is relatively small.4 Postural muscles play an important role in stabilizing the body during vibration. As supportive evidence, in a study by Roll et al.8 it was concluded that foot sole input contributes to the coding and the spatial representation of body posture.
- Improve proprioception. “A loss of proprioception would contribute to neuromuscular dysfunction and likely poor segmental stability in low back pain patients, which may lead to an increase in the risk of injury or further injury. Therefore, to treat patients with low back pain effectively, proprioception training is usually considered to be an important element of the rehabilitation exercise program.”5
- Effectively counteract bone loss. Low level vibration at 30 Hz for 20 minutes per day stimulated a 34 percent increase in the density of trabecular bone in the proximal femur of adult male sheep following one year of treatment.9
- Acutely increase testosterone and growth hormone levels and acutely decrease cortisol levels in healthy individuals when the training protocol was relatively short.10
The exclusion criteria for whole body vibration include pregnancy, acute thromboses, heart or circulatory conditions, fresh wounds, artificial joints or body parts, spinal pathology, diabetes, epilepsy, acute migraines, acute inflammatory conditions, pacemaker, or tumors.11 Higher frequencies (above 60 Hz) and hours of prolonged daily use are also not recommended.4
EXTREME HEAD TRANSLATION CASE STUDY
Recently, a newly graduated, CBP® certified, associate joined our practice. Her name is Dr. Christina Stamm. A friend of Dr. Stamm’s was trying to become a firefighter and was told by the M.D. doing his preliminary physical examination that he had a cerviothoracic scoliosis and could not be approved for the job. He presented at our office to see if Dr. Stamm could reduce his spinal condition to an acceptable level as quickly as possible.
The patient had no subjective complaints and no history of spinal related pain or neurological dysfunction. His range of motion studies were performed with the aid of the J-tech™ computer system, and revealed good flexion, restricted extension, restricted left lateral flexion and restricted bilateral rotation. A 6 percent whole person impairment was given, based on the 5th edition of the AMA guidelines. His postural exam denoted a right lateral translation and forward translation of his head on thorax as well as a high left shoulder tilt. There was palpable, bilateral increased muscle tonus of the lateral and posterior cervical musculature. The initial cervical radiographs showed a 31 millimeter lateral translation of the skull and cervical spine to the right with respect to the vertical axis line drawn from the center of mass of second thoracic vertebrae (See X-ray #1). No degenerative changes were noted and the disc spaces appear to be normal.
The patient was started on a treatment regimen that included Mirror-Image® spinal adjustments and standing, vibratory-assisted, Mirror-Image® cervical lateral translation traction for 18 minutes per session (See Picture #1) at a frequency of two treatments per week. A whole body resonant frequency of 25 to 35 Hz3 with low magnitude (100 lbs. force) was utilized. Most of the industrial grade vibratory platforms sold today have magnitudes of 300 to 400 pounds of force or more. While this may be fine for short duration exercises, it is not good for 10-20 minute traction sessions. Because of the difficulty I experienced in finding a frequency adjustable, low magnitude vibratory platform to assist in the performance of postural/structural corrective traction, I decided to make and offer one, the CT-Vibro-Platform(tm), through my supply company, Circular Traction Supply, Inc. It can be used under most postural/structural corrective traction devices currently on the market. Home Mirror-Image® exercises were also prescribed to the patient.
After ten treatments the patient’s posture appeared greatly improved, so an early re-evaluation was preformed. The patient’s extension improved (55 degrees to 62 degrees), left lateral flexion improved and balanced with right lateral flexion (44 degrees left, 43 degrees right), and rotation improved bilaterally (70 degrees left to 82 degrees left, 76 degrees right to 92 degrees right). The whole person impairment decreased from 6 percent to only 2 percent impairment. The post x-ray revealed a significant reduction of the right lateral translation of the patient’s skull from 31 millimeters to 17 millimeters (See X-ray #2). The high left shoulder now appears to be level. Because of his physical improvement, the patient is now being re-evaluated for the firefighting job he so desires.
- Issurin VB. Vibrations and Their Applications in Sport. A Review. J. Sports Med Phy Fitness, 2005;45:324-336.
- Kelderman J. The Power Plate, A New Application in Physical Therapy. Physical Therapy Thesis Paper, www.powerplateusa.com/research.
- Goel VK, Park H, Kong W. Investigation of Vibration Characteristics of the Ligamentous Lumbar Spine Using the Finite Element Approach. J. Biomech Engineering, Nov 1994;116:377-383.
- Cardinale M, Pope MH. The Effects of Whole Body Vibration On Humans: Dangerous or Advantageous? Acta Physiologica Humgarica, 2003;90(3):195- 206.
- Fontana TL, Richardson CA, Stanton WR. The Effect of Weightbearing Exercise With Low Frequency, Whole Body Vibration on Lumbosacral Proprioception: A Pilot Study on Normal Subjects. Aus J. Physio, 2005;51:259-263.
- Cardinale M, Wakeling J. Whole Body Vibration Exercise: Are Vibrations Good For You? Br J Sports Med, 2005;39:585-589.
- Rittweger J, Just K, Kautzsch K, Reeg P, Feisenberg D. Treatment of Chronic Lower Back Pain with Lumbar Extension and Whole-Body Vibration Exercise: a randomized controlled trial. Spine 2002;27(17):1829-1834.
- Roll R, Kavounoudias A, Roll JP. Cutaneous Afferents From Human Plantar Sole Contribute to Body Posture Awareness. Neuroreport 28, 2002;13(15):1957-1961.
- Rubin C, Turner AS, Bain S, Mallinckrodt C, McLeod K. Anabolism: Low Mechanical Signals Strengthen Long Bones. Nature 2001;412:603-604.
- Bosco C, Iacovelli M, Tsarpela O, Cardinale M, Bonifazi M, Tihanyi J, Viru M, De Lorenzo A, Viru A. Hormonal Responses to Whole Body Vibrations in Man. Eur J Appl Physiol, 2000;81(6):449-454.