The science behind that wobbly feeling on skates By Bill Hauda If you think you are a little wobbly while you are inline skating, just wait until you shed your skates. There's a chance the off-balance
feeling may continue long after your workout. That's the conclusion of researchers at the University of Quebec following a study of recreational inline skaters. The researchers found that inline skating can cause impairment of balance and other motor functions even after the skating is done.  The original research was published in the Journal of Medicine and Science in Sports and Exercise, published by the American College of Sports Medicine. The American Running Association recently published a review of the study in its Running and Fitness newsletter.
Vibrations from the road surface are the reason, said researchers Cynthia
Thompson and Marc Belanger. The pair studied six male and four female recreational skaters. The recreational athletes skated on a 200-meter outdoor stretch of pavement for 35 minutes. The researchers measured the vibrations during skating and then analyzed various motor functions including reflex and ability to detect ankle angle changes after the workout ended. The measurements showed the skating vibrations had been transmitted to
the skaters' lower limbs and each of the motor functions was diminished. The changes were not insignificant. Reflex dropped by 35 percent and remained depressed for more than 30 minutes after inline skating.
The researchers closely controlled other factors that might influence motor function. For example, they had the skaters keep their skates on for 30 minutes after stopping to eliminate the possibility that removal of the skates would influence the study.
The study indicated that impaired balance and the control and execution of simple motor tasks are of concern right after inline skating. The practical impact of the findings, however, is very speculative. It may be that it's not a good idea to go inline skating and then immediately hop in your car to drive home, because motor function such as reflex and ankle angle change detection are impaired.
The study suggested that more research is needed to determine the
relationship of duration of inline skating on intensity of effect. In other words, if you skate for two hours, does the motor function impairment increase? What happens over time to people who regularly inline skate for fitness?
There have been some unrelated studies that give a hint. In 1978, the Scandinavian Journal of Work, Environment and Health carried a report on a study of long-term exposure to vibrations. The finding was that
exposure over a long period can lead to Raynaud's phenomenon. Raynaud's is characterized by sporadic interruptions of blood flow in which there is a whitening of an extremity followed by painful, throbbing return of circulation. Long term exposure can even result in permanent loss of sensation and muscle damage.
In 1998, a report from the International Conference on Hand-Arm Vibration cited a study that showed 80 percent of 100 hand tool
operators had swelling and wasting of the nerves in the hand. It said this was the most frequent reason for those workers changing jobs.
"The International Organization for Standardization's standard for vibrating hand tools predicts that the amplitude of the vibrations the skaters were exposed to in the Canadian study, if increased to two hours per day, could result in stage one of Raynaud's phenomenon in 30
percent of the skaters in just three years," the Running and Fitness article said.
It is interesting that the experience of inline skaters is similar to that of bicyclists. Cyclists who spend many hours on a bike can run into similar problems because vibrations are transmitted from the road through the frame and handlebars to the hand. The cyclists' solution has been to wear padded cycling gloves to protect the hand from the vibrations.
What can skaters do to minimize the potential impact of vibrations? One suggestion is to switch to skates specifically designed to reduce transmission of vibrations. Other suggestions include taking frequent rest breaks and not making inline skating the only form of exercise you do.
To get a ($20) copy of the Thompson-Belanger study, you can find the American College of Sports Medicine at www.acsm.org. The American Running Association is at www.americanrunning.org
| 
