This study was recently published. It filmed runners at the 8.1km mark of the 2011 Milwaukee Marathon to determine the foot strike pattern and correlate that to performance. Here is the abstract
Foot-Strike Pattern and Performance in a Marathon
Mark E. Kasmer, Xue-cheng Liu, Kyle G. Roberts, Jason M. Valadao
IJSPP Volume 8, Issue 3, May 2013, 8, 286 – 292
Purpose: To determine prevalence of heel strike in a midsize city marathon, if there is an association between foot-strike classification and race performance, and if there is an association between foot-strike classification and gender.
Methods: Foot-strike classification (forefoot, midfoot, heel, or split strike), gender, and rank (position in race) were recorded at the 8.1-km mark for 2112 runners at the 2011 Milwaukee Lakefront Marathon.
Results: 1991 runners were classified by foot-strike pattern, revealing a heel-strike prevalence of 93.67% (n = 1865). A significant difference between foot-strike classification and performance was found using a Kruskal-Wallis test (P < .0001), with more elite performers being less likely to heel strike. No significant difference between foot-strike classification and gender was found using a Fisher exact test. In addition, subgroup analysis of the 126 non-heel strikers found no significant difference between shoe wear and performance using a Kruskal-Wallis test.
Conclusions: The high prevalence of heel striking observed in this study reflects the foot-strike pattern of most mid-distance to long-distance runners and, more important, may predict their injury profile based on the biomechanics of a heel-strike running pattern. This knowledge can help clinicians appropriately diagnose, manage, and train modifications of injured runners.
Not surprisingly, 94% were heel strikers and there was a statistically significant difference between the foot strike classification and race rank, with the forefoot strikers ranking ahead of the split strikers (asymmetry between left and right) who ranked ahead of the midfoot strikers who ranked ahead of the heel strikers. The 94% is similar to that reported by Larsen et al of 89% heel striking at the 10km mark and 93% at the 32km mark of a marathon. Larsen et al also reported no correlation between foot strike pattern and performance which the above study did find. The authors explanation for this difference was that in the Larsen et al study, the winning time was 2:55:16, compared to the above 2:22:17, so there were more runners running faster. Larsen et al had 266 heel strikers; 10 asymmetrical; 10 midfoot and no forefoot strikers; whereas the above study had 1865 heel strikers; 14 asymmetrical; 101 midfoot and 11 forefoot strikers so is powered more to find a significant difference.
This is a reasonably good descriptive study and that it all. It does not show that if you forefoot or midfoot strike that you will run faster, though I am sure some will find a way to interpret it that way. There are plenty of elite runners who run fast while heel striking (see the picture here).
As always, I go where the evidence takes me.