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Impact Loading Can be Reduced with a Midfoot Strike Pattern

2581

Board #189 June 4 9:00 AM - 10:30 AM

Altman, Allison R.; Davis, Irene S., FACSM

Medicine & Science in Sports & Exercise: May 2010 - Volume 42 - Issue 5 - p 676-677
doi: 10.1249/01.MSS.0000385887.68407.fc
E-36 Free Communication/Poster - Sport Biomechanics: JUNE 4, 2010 7:30 AM - 12:30 PM: ROOM: Hall C
Free

University of Delaware, Newark, DE.

Email: aaltman@udel.edu

(No disclosure reported)

Most runners strike the ground with a rearfoot strike (RFS) pattern, 25% of runners land with a midfoot strike (MFS) pattern, and less than 1% land with a forefoot strike (FFS) pattern. RFS patterns are characterized by a transient vertical impact peak (IP), which is associated with high average and instantaneous vertical loading rates (AVLR, IVLR). When excessive, these have been shown to be associated with a number of running related injuries. It has been well-documented that impact loading is significantly reduced in a FFS pattern. This reduction has been attributed, in part, to a shorter (SL). Our previous research suggests that loading during a MFS pattern is not reduced from a RFS pattern. However, the study only included runners who naturally run with a RFS pattern.

PURPOSE: To investigate impact loading variables in runners with a natural MFS pattern. It was hypothesized that these runners would have reduced impact loading, as well as a shorter SL, compared to runners with a natural RFS pattern.

METHODS: This is an ongoing study of which 15 runners, 10 with a natural RFS and 5 with a natural MFS have been recruited to date. Subjects ran with their natural pattern on an instrumented force treadmill at a self-selected speed (RFS=2.96±0.4, MFS=3.0±0.4 m/s) for 5 min. IP, AVLR, IVLR and SL, were extracted from the analog data.

RESULTS: IP, AVLR and IVLR were reduced between 12-16% in the natural MFS condition. Surprisingly, the SLs were fairly similar between MFS and RFS.

CONCLUSIONS: These preliminary results suggest that habitual MFS running is associated with reduced impact loading. This may provide justification to recommend a MFS pattern for injured runners with high impact loading.

ACKNOWLEDGEMENTS: NIH 1 S10 RR022396, DOD W911NF-05-1-0097

© 2010 American College of Sports Medicine