Born to Run?
Perhaps we really were born to run. This study looks at the forefoot, the phalanges and their potential role in the evolution of our feet.
We know impact forces increase with running, so it makes sense that physical and metabolic demand to continue forward momentum would increase as well. Longer lever arms (such as longer toes) would require greater torque on the muscles as well as increased lift of the foot (to provide ground clearance), and most likely a different orientation of the rearfoot and trochlea that the flexor tendons would have to pass through. This would probably result in a more cavus, rigid foot as well.
The study did not state, but suggested muscular recruitment of the flexors is distinctly different in walking vs running, and that there is less “balance” between the flexors and extensors. We contend that with appropriate gait patterns (ie, using the glutes as a primary hip extensor), long flexor activity would be more balanced with long extensor activity and this disparity would not be seen.
The video has nothing to do with the study, we just thought it was pretty funny
Sorting out the details so you don’t have to; The Gait Guys
J Exp Biol. 2009 Mar;212(Pt 5):713-21. Walking, running and the evolution of short toes in humans. Rolian C, Lieberman DE, Hamill J, Scott JW, Werbel W. Source http://www.ncbi.nlm.nih.gov/pubmed/19218523
Department of Anthropology, Harvard University, Cambridge, MA 02138, USA. cprolian@ucalgary.ca
Abstract
The phalangeal portion of the forefoot is extremely short relative to body mass in humans. This derived pedal proportion is thought to have evolved in the context of committed bipedalism, but the benefits of shorter toes for walking and/or running have not been tested previously. Here, we propose a biomechanical model of toe function in bipedal locomotion that suggests that shorter pedal phalanges improve locomotor performance by decreasing digital flexor force production and mechanical work, which might ultimately reduce the metabolic cost of flexor force production during bipedal locomotion. We tested this model using kinematic, force and plantar pressure data collected from a human sample representing normal variation in toe length (N=25). The effect of toe length on peak digital flexor forces, impulses and work outputs was evaluated during barefoot walking and running using partial correlations and multiple regression analysis, controlling for the effects of body mass, whole-foot and phalangeal contact times and toe-out angle. Our results suggest that there is no significant increase in digital flexor output associated with longer toes in walking. In running, however, multiple regression analyses based on the sample suggest that increasing average relative toe length by as little as 20% doubles peak digital flexor impulses and mechanical work, probably also increasing the metabolic cost of generating these forces. The increased mechanical cost associated with long toes in running suggests that modern human forefoot proportions might have been selected for in the context of the evolution of endurance running.
