With this feedback, all runners immediately were able to modify the hardness of their footstrike to meet the desired level, but all reported that the softer footstrike level did not "feel normal." By the end of the eighth session, however, even when they were receiving relatively little feedback, all runners had adjusted the force of their footstrike by half. Furthermore, they reported that they found the new gait now felt more normal.
The runners experiencing pain under the kneecap followed the same protocol. Dr. Davis earlier gait mechanics studies had found that individuals with kneecap pain (patellofemoral pain syndrome) demonstrate poor hip stability, hips rotating inward, causing a knock-kneed type running gait. On the laboratory treadmill, these runners watched a monitor that compared their gait, measured by markers on their legs, to a normal angular curve.
By keeping their knees apart, not letting them collapse inward, they soon were able to make the two images merge. Before retraining, the group had classified their kneecap pain from five to seven on a ten point scale, ten being the worst. In every case, after retraining, the runners reported zero pain.
A month after the retraining, during which runners had resumed their regular running schedule, they
Contact: Sylvia Wrobel
Federation of American Societies for Experimental Biology