By Jordana Bieze Foster
Shortening step length and switching foot strike pattern both effectively decrease patellofemoral joint loading during running, according to research from East Carolina University in Greenville, NC, presented in February at the annual Combined Sections Meeting of the American Physical Therapy Association.
In 26 college-age runners, the investigators found that a 10% decrease in step length was associated with an 18% decrease in average peak patellofemoral joint reaction force (PFJRF) and a 14% decrease in peak patellofemoral joint stress (PFJS). Switching from a rearfoot strike pattern to a forefoot strike pattern was associated with a 10% drop in each variable.
Per-step decreases in PFJRF-time integral (23% per 10% decrease in step length; 13% for switching strike pattern) and PFJS-time integral (18% and 11%, respectively) were maintained when the researchers calculated corresponding per-mile values, despite the increased number of shortened steps per mile. PFJRF-time integral dropped 13% per mile for each of the two load-reducing strategies, and PFJS dropped 10% per mile for each 10% decrease in step length and 11% per mile for switching strike pattern.
Source:
Ratcliff OM, Loss J, Warren JM, et al. Modifications of foot-strike pattern and step length to decrease patellofemoral joint loads during running. J Orthop Sports Phys Ther 2014;44(1):A60.
