https://me.queensu.ca/People/Deluzio/JAM/files/Lundgren2007_01.pdf

Invasive in vivo measurement of rear-, mid- and forefoot motion during walking

Whole body inverse dynamics over a complete gait cycle based only on measured kinematics

Foot kinematics during walking measured using bone and surface mounted markers.

The human foot is characterized by a pronounced longitudinal arch (LA) that compresses and recoils in response to external load during locomotion, allowing for storage and return of elastic energy within the passive structures of the arch and contributing to metabolic energy savings. Here, we examine the potential for active muscular contribution to the biomechanics of arch deformation and recoil. We test the hypotheses that activation of the three largest plantar intrinsic foot muscles, abductor hallucis, flexor digitorum and quadratus plantae is associated with muscle stretch in response to external load on the foot and that activation of these muscles (via electrical stimulation) will generate sufficient force to counter the deformation of LA caused by the external load. We found that recruitment of the intrinsic foot muscles increased with increasing load, beyond specific load thresholds. Interestingly, LA deformation and muscle stretch plateaued towards the maximum load of 150% body weight, when muscle activity was greatest. Electrical stimulation of the plantar intrinsic muscles countered the deformation that occurred owing to the application of external load by reducing the length and increasing the height of the LA. These findings demonstrate that these muscles have the capacity to control foot posture and LA stiffness and may provide a buttressing effect during foot loading. This active arch stiffening mechanism may have important implications for how forces are transmitted during locomotion and postural activities as well as consequences for metabolic energy saving.

/pdf/intrinsic-foot-muscles-have-the-capacity-to-control-5d6dqzu9wb.pdf

Intrinsic foot muscles have the capacity to control deformation of the longitudinal arch

The human foot was anatomically modern long before footwear was invented, and is adapted to barefoot walking on natural substrates. Understanding the biomechanics of habitually barefoot walkers can provide novel insights both for anthropologist and for applied scientists, yet the necessary data is virtually non-existent. To start assessing morphological and functional effects of the habitual use of footwear, we have studied a population of habitually barefoot walkers from India (n = 70), and compared them with a habitually shod Indian control group (n = 137) and a Western population (n = 48). We focused on foot metrics and on the analysis of plantar pressure data, which was performed using a novel, pixel based method (Pataky and Goulermas 2008, Journal of Biomechanics, 41, 2136). Habitually shod Indians wore less often, and less constricting shoes than Western people. Yet, we found significant differences with their habitually barefoot peers, both in foot shape and in pressure distribution. Barefoot walke...

P Lundgren

Papers

Invasive in vivo measurement of rear-, mid- and forefoot motion during walking

Foot kinematics during walking measured using bone and surface mounted markers.

Intrinsic foot kinematics measured in vivo during the stance phase of slow running