A recent study published in the June edition of Journal of Pediatric Orthopaedics examined the effects of heavy cushioned heel running shoes on competitive track athletes. They compared their gait in large heeled trainers to how they ran in racing flats and barefoot. Greater then 70% of the runners had a heel strike with the cushioned shoe which was not present less then 30 percent of the time in the other conditions. Runners adopted a more natural forefoot / midfoot strike pattern when running barefoot or with racing flats. The conclusion, training in heavily cushioned trainers by the competitive runner has not been clearly shown to be detrimental to performance, but it does change the gait pattern. They go on to suggest that It is not known whether the altered biomechanics of the heavily heeled cushioned trainer may be detrimental to the adolescent runner who is still developing a running style.
Knowing the detrimental effects heel striking has on the body without shoes, this study coincides with the philosophy that traditional running shoes can interfere with a natural running gait leading to the possibility of increased injury and decreased efficiency.
See the abstract at Pub Med.