The potential strength of the foot might make it the most underrated region of the human body. It's the last contact with the ground in a running stride, a mobile adaptor to absorb huge amounts of shock in single leg stance, and a rigid propulsive lever for pushing off, changing direction, hopping and jumping. 26 bones, 33 joints and over 20 muscles. And yet, it's a part of the body we generally neglect. Out of sight out of mind.

The longitudinal arch of the foot has the ability to behave like a spring during the stance phase of running (1). During stance phase the foot pronates and the tendons undergo stretch and store elastic energy, which then becomes available during recoil for propulsion (1). The foot spring mechanism has been shown to contribute anywhere between 6% and 17% of the energy necessary for running gait, suggesting major potential energy savings (3).

With the foot able to behave as an energy saving spring, it’s clear that the presence of a longitudinal arch has important implications for energy savings, efficiency and performance.

The inability to form a longitudinal arch coincides with excessive compliance, as a compliant foot is very adept at shock absorption, yet unable to form a rigid level for propulsion. Weakness of the intrinsic foot musculature can result in an inability to create this essential arch and foot spring (3).

Individuals with higher longitudinal arches recorded stiffer leg springs than low-arched runners (2) and may possess a greater ability to utilise the foot spring and save energy via elastic mechanisms in the foot.

Kelly et al. 2014 have demonstrated that improving the strength of the intrinsic foot muscles (most specifically abductor hallucis) can result in an improved ability of the intrinsics to specifically reform the longitudinal arch.

Most studies that have investigated foot strengthening exercises have traditionally focussed on their ability to alleviate pain or recover from injury. Few studies look at the importance of foot strengthening for improving one's functional ability.

At Mechanics of Movement we are all about improving movement to maximise function. Foot strengthening fits in this basket. How much potential does this mobile adaptor, powerful lever have? How can we maximise this ability?

It's for the above reasons that we believe foot strengthening is an integral part of moving well.

1. Ker, R. F., Bennett, M. B., Bibby, S. R., Kester, R. C. and Alexander, R. M. N. The spring in the arch of the human foot. Nature. 325: 147-149. 1987

2. Williams, D. S., Davis, I. M., Scholz, J. P., Hamill, J., & Buchanan, T. S. High- arched runners exhibit increased leg stiffness compared to low-arched runners. Gait and Posture. 19(3): 263-269. 2004

3. Stearne et al. The Foots Arch and the Energetics of Human Locomotion. Scientific Reports. 6(19): 1-10. 2016

4. Kelly et al. Intrinsic foot muscles have the capacity to control deformation of the longitudinal arch. Journal of the Royal Society Interface. 11(93): 1-15. 2014.