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Vertical Impact Loading in Runners with a History of Patellofemoral Pain Syndrome


Board #205 June 4 9:00 AM - 10:30 AM

Davis, Irene S., FACSM1; Bowser, Brad J.1; Hamill, Joseph, FACSM2

Medicine & Science in Sports & Exercise: May 2010 - Volume 42 - Issue 5 - p 682
doi: 10.1249/01.MSS.0000385903.65728.85
E-36 Free Communication/Poster - Sport Biomechanics: JUNE 4, 2010 7:30 AM - 12:30 PM: ROOM: Hall C

1University of Delaware, Newark, DE. 2University of Massachusetts Amherst, Amherst, MA.

(No disclosure reported)


Patellofemoral pain syndrome (PFPS) is one of the most common overuse injuries seen by medical professionals. Abnormal lower extremity movement patterns have been linked to PFPS in runners. However, the role of abnormal forces has not been examined. Vertical impact loading has been associated with a number of conditions including plantar fasciitis, tibial stress fractures and knee osteoarthritis. It is possible that increased vertical impact loading may also be associated with PFPS.

PURPOSE: To examine vertical impact loading in runners with a history of PFPS.

METHODS: This is an ongoing study of which 8 female rearfoot strike (RFS) runners (24.3 yrs, 26.2 miles/wk) with a past history of PFPS have been collected to date. The condition had to be diagnosed by a medical professional and be of duration of greater than 30 days. 8 female RFS runners (24.7 yrs, 26.7 miles/wk) with no history of any knee related injuries served as controls (CON). Tibial accelerometry and ground reaction forces were collected at 1080 Hz as subjects ran along a 25 m runway at 3.7 m/s, striking a force plate at its center. Peak positive acceleration (PPA), vertical impact peak (VIP) and vertical instantaneous and average load rates (VILR, VALR) were compared between groups.

RESULTS: PFPS runners exhibited significantly greater VIP and VALR than the CON group (Fig. 1). PPA (ES=0.46, p=0.366) and VILR (ES=1.0) were not significantly greater, but were associated with moderate to large effect sizes.



CONCLUSIONS: Runners with a history of PFPS exhibit higher than normal impact loading. Prospective studies are needed to establish causation. However, interventions aimed at reducing this loading may be beneficial for these individuals.

Study supported by: DAMD17-00-1-0515

© 2010 American College of Sports Medicine