Researchers Take a Step Forward to Understand the Human Foot
Orange County, CA - January 16th, 2019 - Unlike chimpanzees where they have opposable thumbs on all four hands, humans have evolved arched feet, to improve upright walking.
Prior research proposed that the arches were to be supported by the plantar intrinsic muscles (PIMs). However, a new study by researchers at the University of Queensland and the University of Exeter shows that PIMs have a "minimal impact" on this.
"Recent research suggests that muscles in our feet are key to how the foot functions during walking and running. Our study provides direct evidence showing the significance of these foot muscles in supporting the performance of the human foot. Contrary to expectations, PIMs contribute minimally to supporting the arch of the foot during walking and running. However, these muscles do influence our ability to produce forward propulsion from one stride into the next," said lead author Dr. Dominic Farris, of the University of Exeter.The researchers tested the PIMs by comparing foot and lower limb movement with and without a nerve block that prevented contraction of the muscles. While ground contact was made with walking and running, the stiffness of the foot arch wasn’t altered by the block, showing that the PIMs' contribution to arch support is minimal, probably due to their small size.
Nevertheless, with the PIMs blocked, the distal joints of the foot could not be stiffened sufficiently to provide normal push off against the ground."This could have implications for understanding conditions such as flat feet, the value of training foot muscles and ideas around potential benefits of running barefoot," said Dr. Farris.
The muscles aren’t crucial for supporting the arch of the foot, but they are essential for propelling us forward when walking or running.
