EB: Correct Runners' Gaits, Cut Injuries with Sound and Mirrors

WASHINGTON, April 30 -- Retraining runners' gait patterns reduces or eliminates common injuries, researchers said here.

Runners with knee pain from tibial stress fractures or patellofemoral pain syndrome who underwent an eight-session biofeedback program reduced pain by 50% to 100%, said Irene Davis, Ph.D., of the Running Injury Lab at the University of Delaware in Newark.

She noted that 76% of runners injure themselves in a year. "We know that this is related in part to how they run--their mechanics."

To prevent reinjury, changing gait mechanics is key, Dr. Davis said. She reported preliminary outcomes of gait retraining from two small studies here at the Experimental Biology meeting.

Both studies included five runners who were having or were at high risk for two of the most common running-related injuries-tibial stress fractures and patellofemoral pain syndrome.

Each patient first underwent a gait analysis. Then, at each of eight sessions, participants ran on a treadmill while connected to biofeedback equipment. The sessions lasted 15 minutes initially and built up to 30 minutes over the two- to four-week study period.

Over the final four sessions, the feedback was gradually removed. Runners were not allowed to run outside the laboratory during retraining to prevent them from reinforcing their old gait habits.

The first study used this protocol for patients with tibial stress fractures, which the researchers had previously linked to hitting the ground hard on each footstep.

These participants wore a shock-measuring device on their lower legs while running on the treadmill. A monitor displayed the force of each footstrike measured against what normal force should be.

The patients were asked to constantly adjust the hardness of their footsteps to stay at or below normal force.

Although all patients reported that the new gait pattern felt strange at first, by the end of the training program they had reduced the force of their footsteps by 50% on average.

Follow-up visits at one month showed that the changes persisted. One patient who came back at one year had also maintained the new gait pattern, Dr. Davis said.

The second study enlisted patients with patellofemoral pain syndrome, characterized by pain under the kneecap. Prior research indicated that these patients' hips rotate inward producing a knock-kneed running style.

As these patients ran on a treadmill, markers on their legs provided feedback on the position of their knees. Again, patients watched their gait on a monitor compared to a normal gait and were told to keep their knees apart without letting them collapse inward.

After the eight sessions, patients' kneecap pain dropped from five to seven points on a 10-point scale--to zero in every case. At a one-month follow-up, all retained the new gait pattern despite returning to their normal running schedule.

Many patients are prescribed cushioning footwear or orthotics to change the way the foot strikes the ground, but these are going to be ineffective if the cause is at the hip, Dr. Davis said. And cushioned shoes typically improve shock by only 10%, she noted.

"As humans we are very adaptable," she said. "Retraining is better than foot wear or orthotic modifications."

Although few clinicians have access to the kind of biofeedback equipment used in the studies, Dr. Davis said the same techniques can be used without it. "You don't have to have high tech equipment," Dr. Davis said. "Both of the protocols, I think, can be translated into the clinic."

She said she has used a mirror for patients with patellofemoral pain syndrome. They watch the position of their knees as they run in place.

"For people who are hitting the ground too hard, tell them to listen to their footsteps and ask them to try to make them softer," Dr. Davis added.

She suggested enlisting the help of a physical therapist for gait analysis.

Dr. Davis said one patient she retrained using a mirror had good results, but she said it is too early to speculate whether the results outside the lab would be as good as inside.

She said her group hopes to complete a study comparing the two methods to see if the outcomes are similar. Meanwhile, the two studies are continuing to accrue patients with the goal of 60 runners.

While gait retraining in the clinic may rely on patients' motivation to practice these techniques, Dr. Davis said she has seen no problems with willingness.

"Runners are such a good group," she said. "They are so motivated to continue to run."

"The hardest part of this, though, is keeping people [from] running outside the program," she said.