Foot Strike Patterns Of Runners During A 100 Mile Ultramarathon

Abstract

Foot-strike patterns can have major implications on long distance running performance and injuries. While foot-strike patterns have been examined during traditional long distance events, such as half and full marathons, little research has been conducted on events longer than 26.2 miles. PURPOSE: To classify foot-strike patterns and their effect on race performance during a 100 mile ultramarathon. METHODS: Foot-strike patterns were recorded at four intervals for 40 runners at the Beyond Limits Ultramarathon, a 100 mile race consisting of a 2 mile loop, in Mountain Center, CA. One Casio EX - FH1000 high speed camera (Tokyo, Japan) sampling at 240 HZ was used to film runners from the waist down at miles 11.5, 31.5, 61.5, and 91.5. Video analysis was conducted to identify foot-strike patterns for each runner. RESULTS: Rearfoot (RF) foot-strike pattern was observed most frequently among runners (mile 11.5: 69.6%; mile 31.5: 54.3%; mile 61.5: 30.4%; mile 91.5: 26.1%). As the race progressed, the decrease in RF frequency was associated with an increase in Walking (mile 11.5: 4.3%; mile 31.5: 32.6%; mile 61.5: 34.8%; mile 91.5: 30.4%). Remaining runners were identified as either midfoot (MF) or undefined (shuffling). No runners were observed as striking exclusively forefoot (FF) at any of the collection points. In addition, there were no significant differences (p>.05) in pace as a result of foot-strike type at any of the collection points. CONCLUSION: The predominance of rearfoot-strikers throughout the event is consistent with similar research conducted on shorter running events. The lack of significance between foot-strike pattern and race order could be attributed to the overall length of the event. Research on shorter events has found that increases in speed encourage midfoot or forefoot strikes, however the current findings did not. This may be due to extraneous factors affecting runners over the course of 100 miles.