Metabolic and Mechanical Energy Saving Mechanisms in Barefoot vs. Shod Human Running
presentationposted on 21.07.2014, 00:00 by Leslie Fischer
Many runners purchase expensive shoes with enhanced support believing that these shoes will make them faster, and reduce the chance of developing a running related injury. However, shoes with enhanced support have been shown to lead to more leg injuries and require more metabolic energy than running barefoot. Here we will investigate the apparently paradoxical recent results of Lieberman et al. (Nature, 2010) who found lower metabolic rates and a reduced potential for injury among habitual barefoot runners. These results are paradoxical because previous investigations have found that barefoot runners use greater muscle volumes and rates of force generation (1/Tc) compared to shod runners; two muscular contractile properties that would be expected to raise, not lower, the rates of muscle metabolism. To investigate the relationship between muscle function and metabolic energy use during barefoot versus shod human running, we measured rates of oxygen uptake through indirect calorimetry, volumes of active muscle via surface electromyography, and rates of force production from foot-ground contact duration. Subjects completed duplicate running trials at four speeds in three differing experimental conditions; traditional running shoes, barefoot, and a new shoe designed to mimic the barefoot condition. We specifically predict that the lesser stance average ground support forces required of barefoot running explains the increased running economy of the barefoot condition.