Too Much Bounce in your Run?

The relationship between running injuries and the amount of vertical force (up and down movement and impact) during running has been well-documented through many recent studies. “Vertical ground reaction force” (VGRF) is the force that the ground exerts up through a runner’s leg when landing. The rate at which these forces are applied to the body is called “vertical impact loading rate” (VILR). So if the vertical ground reaction forces are applied too quickly and not absorbed well, injury risk can be increased significantly.

Researchers from the University of Tennessee and Drexel University conducted a study to determine if using a decibel meter as feedback during treadmill running could help to lower both VGRF and VILR, and therefore injury risk. Data was collected for a group of 14 healthy recreational runners as they ran over ground; they had an above average VILR. Immediately after, the runners ran on a treadmill at the same pace and received visual feedback from the decibel meter. Runners were instructed to decrease the decibel level as much as possible. After retraining on the treadmill participants ran over ground, again at the same speed, and were reminded to use the strategy developed during the treadmill retraining.

Data analysis showed significant reductions in VGRF and VILR after the decibel meter feedback technique retraining compared to baseline running. 80% of the runners in the study made reductions of 20% or greater. These results are consistent with other literature on the topic, but the researchers note that further study is needed to find the best type and amount of sound intensity training, and to determine if the retraining translates to long-lasting changes in running form. Using a decibel meter may help to improve running form by decreasing the peak vertical force acting on the body and the rate at which it is applied.

These changes may help to reduce injury risk during long distance recreational running, but more specific guidelines from future studies will be helpful to determine how this could be best worked into training plans for a wide variety of runners.

Tate, JJ Milner, CE. Sound-Intensity Feedback During Running Reduces Loading Rates and Impact Peak. JOSPT. 47(8);565-569


Dr. Cathlin Fitzgerald, DPT, CSCS
Tyler Denn-Thiele SPT