The influence of foot posture on the cost of transport in humans

Abstract

SUMMARYAlthough humans appear to be specialized for endurance running, the plantigrade posture of our feet, in which the heel contacts the substrate at the beginning of a step, seems incompatible with economical running. In this study, we tested the hypothesis that plantigrade foot posture reduces the energetic cost of transport (COT) during walking in humans. When human subjects walked with their heels slightly elevated in a 'low-digitigrade' posture, COT increased by 53% above that of normal plantigrade walking. By contrast, there was no difference in COT when subjects ran with digitigrade versus plantigrade foot posture. Stride frequency increased and stride length decreased when subjects switched to digitigrade walking; however, this change did not influence the COT. Additionally, we found that possible reductions in postural stability appear not to have caused the elevated cost of digitigrade walking. Digitigrade walking, however, did (1) increase the external mechanical work performed by the limbs; (2) reduce the pendular exchange of kinetic and potential energy of the center of mass; (3) increase the average ground reaction force moment at the ankle joint; and (4) increase the recruitment of major extensor muscles of the ankle, knee, hip and back. These observations suggest that plantigrade foot posture improves the economy of walking. Relative to other mammals, humans are economical walkers, but not economical runners. Given the great distances hunter-gatherers travel, it is not surprising that humans retained a foot posture, inherited from our more arboreal great ape ancestors, that facilitates economical walking.

The role of plantigrady and heel-strike in the mechanics and energetics of human walking with implications for the evolution of the human foot

“…Humans represent an exception to this pattern (Cunningham et al, 2010) as we possess adaptations for endurance terrestrial running (Bramble and Lieberman, 2004;Carrier, 1984), combined with plantigrade feet and a prominent heel strike (HS), during walking gaits, where the foot touches down heel first on the calcaneal tuberosity in a dorsiflexed posture, without mid-or forefoot contact. Given the importance of limb length to cursorial mammals, it is uncertain why humans use a plantigrade foot posture with a consistent HS during walking (Cunningham et al, 2010).…”

Effect Of Step Rate On Foot Strike Pattern And Running Economy In Novice Runners

“…In previous studies where RE has been measured during different FSP conditions, submaximal VO 2 hasn't differed significantly between FFS and RFS (Ardigo et al, 1995;Cunningham et al, 2010;Perl et al, 2012). In contrast, we found that SI changes in each SR condition showed substantial shifts in FSP and when comparing the difference in VO 2 under the two SR conditions (±10% from preferred) that on average produced the greatest alteration and gap in FSP, we did find significant differences in VO 2 between the -10% SR condition and the +10% condition .…”

“…In studies where RE has been measured during different FSP conditions, submaximal oxygen consumption (VO 2 ) was not different between FFS and RFS (Ardigo, Lafortuna, Minetti, Mognoni, & Saibene, 1995;Cunningham, Schilling, Anders, & Carrier, 2010;Perl et al, 2012). Tartaruga et al (2012) found that distance runners running at the same treadmill speed and the same physiological intensity had SR and internal ankle angles at foot strike (which relate to FSPs) that made up 23% and .6%, respectively, of the biomechanical factors affecting RE.…”

La biomecanica y psicomotricidad del corredor como factores determinantes para el apoyo del antepie en la carrera

“…La falta relativa de pelo en el cuerpo, la capacidad excepcional para sudar y almacenar energía de forma elástica en los músculos y tendones del tobillo 1,2. El consumo aeróbico que manifiesta en las largas distancias, y los dedos del pie más cortos parecen ser adaptaciones para la carrera de resistencia 3 . Además muchos creen que la carrera está en nuestros genes porque el Homo tuvo que correr para alcanzar a la presa antes de la invención de los arcos y las flechas 2 .…”

“…Es decir, el talón durante la marcha contacta con el suelo y absorbe energía en el inicio de la ejecución del paso; se espera que este mecanismo limite el almacenamiento y la recuperación de energía elástica en los mús-culos extensores de la articulación del tobillo. Este tipo de apoyo nos hace ser andadores económicos pero no corredores económicos 3 . Independientemente del porqué empezamos a correr, es evidente que se hizo sin zapatos; el primer ejemplo de calzado se remonta a más de 10.000 años cerca de Fort Rock.…”