In addition, when subjects were grouped by strike type, individuals who used FFS and MFS landings (all but one of which was minimally shod) had significantly more plantarflexed ankles, flexed knees, and flexed hips at the moment of foot strike than individuals who use RFS landings. These kinematic differences were no longer evident click here by midstance. These data corroborate previous reports that barefoot and minimally shod runners tend to differ from habitually shod runners in a number of aspects of running form.19 The data also highlight the general kinematic similarity between forefoot

and midfoot striking, both of which differ from rearfoot striking in a number of respects, perhaps the most important being less overstride in which the ankle lands nearly below the knee at the moment of strike, providing more limb compliance at the ankle and knee. Previous studies have found that shod runners are more likely to FFS at higher speeds,47 and one study found an increased use of FFS at higher speeds among the Daasenech, a habitually barefoot population from northern Kenya that does not run very much, and which lives in a very sandy habitat.48 In contrast, this study found no effect of

speed on strike type. One explanation for this result could be that the range of speeds employed was not great (2.3–4.8 m/s), first with most runners choosing approximately selleck chemical 3.3–3.9 m/s. In addition, many of the runners already used FFS and MFS landings. It was not possible to test for the effect of sex on strike type, but there was no effect of age, body mass, preferred step frequency on strike type variation. Future research is therefore needed to understand when and why runners who are minimally shod or barefoot adopt different strike types. In this regard, additional variables to consider are how strong the runner is, especially in terms of the triceps surae and the foot muscles, the effects of distance and fatigue, and the influence of variations in the hardness,

roughness, or slipperiness of the substrate. Since minimal shoes such as huaraches presumably allow less proprioception than being barefoot but considerably more than standard running shoes (a hypothesis that merits careful testing), it is reasonable to hypothesize that substrate characteristics have less of an effect on strike type choice among minimally shod than barefoot runners, but that other factors related to the skill of running long distances such as overstride, cadence, and posture remain just as important, perhaps even more so when running very long distances. Although the focus of this study was on strike type, the results presented here also provide evidence for an effect of footwear on arch morphology and function.