Jan 29, 2015Pre-Show Primer: Whole-Body Vibration Therapy
Vibration therapy has been growing in popularity in recent years, and its proponents tout a long list of potential athletic benefits. On Wednesday, June 23, David Bazett-Jones, MS, LAT, CSCS, of the University of Wisconsin-Milwaukee, will explain how vibration is used and why it produces results a workshop entitled “Practical Applications of Whole-Body Vibration in Athletic Training Practice.” T&C covered whole-body vibration therapy in 2006 and talked to several athletic trainers who have found success using it. Here’s some of what we learned:
Vibration training can be implemented in a variety of ways. “There are three main groups of platforms,” says Patrick Jacobs, PhD, CSCS, a professor at Florida Atlantic University. “There’s the up-and-down platform that has vertical and horizontal vibration, and a teeterboard-style platform that produces mostly vertical vibration. These typically work by having the athlete stand on the plate to stretch or do exercises using either body weight or a weighted vest. The third type is a larger up-and-down platform that has enough space for users to perform weight-training exercises, such as squats, bench presses, dead lifts, and cleans.”
The basic biomechanical function of this training begins with abrupt impulses delivered with a frequency that typically ranges from 25 to 60 impulses per second, which is usually reported in hertz (Hz). Those impulses send signals to different sensory receptors, which are carried to the central nervous system.
So for a setting of 30 Hz for 30 seconds, the body receives 900 impulses, forcing 900 involuntary contractions in each muscle the impulses reach. “Each of those bursts probably has a benefit in terms of neurological input for reorganization,” says Jacobs. “They are introduced simultaneously to all of the involved muscles. So at the same time there’s a burst going to the hamstring, there’s a burst going to the quad and all the adductor groups.”
The next important variable in WBV is amplitude, or the vertical displacement setting. Amplitude multiplied by the frequency, creates the average velocity or rate of acceleration/deceleration. “The rate of deceleration determines the G-load at that impulse–and it’s the G-load that is likely to determine how much work the muscles are doing,” says Jacobs. “So when using the same frequency, but doubling the displacement from two to four millimeters, the average velocity doubles along with the work the muscles have to do.”
In teeterboard-style platforms, the vertical displacement is based on the concept of a center fulcrum and alternating right-left and up-down motions, which produce a corresponding teeterboard motion at the pelvis. Benefits of the teeterboard motion include simulating a natural crossover pattern that requires active user participation to maintain postural stabilization.
Because the technology is so young, and research data so scarce, most experts agree that users need to proceed cautiously when introducing athletes to vibration. Though it may seem relatively low-impact (athletes report hardly feeling vibration effects during application), it’s wise to progress slowly. After all, at this point nobody knows for certain where the overtraining limits of vibration lie.
“The bottom line is, we don’t know much about the biological effects,” says Jacobs. “We know from a peripheral level what’s going on when you apply vibration, but most of the hows and whys are still very fuzzy.”
For beginners, Craig Friedman, ATC, CSCS, a performance specialist at Athlete’s Performance in Tempe, Ariz., uses the lowest amplitude at 30 Hz for 30 seconds. When the athlete becomes comfortable with that, Friedman increases the duration. The next step is to change the rest-to-work ratio between sets.
“After adjusting the rest-to-work ratio, we change the body position and the movement to make it more complex,” says Friedman. “For example, if we start with a pillar bridge on their knees, we’ll progress to having them use their feet. Or if they’re doing something on two feet, we’ll have them go to one foot. After all that, we raise the frequency and amplitude.”
Friedman calculates progression rates on an individual basis. “It’s a qualitative assessment of how the athlete is recovering from their previous training sessions,” he says. “Typically it takes about a week before an athlete is ready to progress, but for some it can take more or less time for to feel comfortable at a certain level.”