I’ve been thinking a lot lately about foot pain – not only because I am treating one of my athletes for this (among many others with close neighbor chronic ankle sprains), but also because it is an injury I am struggling with myself. I come from a foundation that attributes some of foot and ankle dysfunction up the chain to the core and glutes, with robust literature to support. Therapy may look like adding support to the foot & ankle complex to provide good alignment and then strengthening on top of that. And I still believe this relationship to be true; however, I think sometimes in this mindset we forget about the foot.
The same types of sensory receptors are also found on the soles of your feet. However, we generally have to keep our feet covered most of the day for safety reasons, like avoiding stepping on glass. This already leads to a decrease in the amount of information sent to your brain with each step. Then on top of that, add support shoes (generally including a thicker sole) and/or orthotics and this only further decreases the information received through the sole of the foot. So why is this important?
When the brain receives sensory information, it reacts by preparing the motor system for an appropriate response. For the feet, we are talking about the muscles that help with stability and balance. It’s no coincidence that these are often the targets of a lot of rehabilitation work post injury. In 2014 a study was published in BMC Sports Science titled “Cutaneous stimulation of discrete regions of the sole during locomotion produces ‘sensory steering’ of the foot.” In the study, authors Zehr et al delivered non-noxious stimuli to different locations on the sole of the foot during treadmill walking. Using EMG, they found that with various stimuli, specific muscle activity up the leg was increased (particularly the peroneals, gastrocnemius, tibialis anterior – those same muscles that help with stability and balance). The findings of the study add to existing evidence that stimuli to the sole of the foot provide important input to the brain for overall movement competence.
This is interesting as it relates to rehabilitation. Not only for foot injuries, but also for the chronic ankle sprain cases that I mentioned earlier. In another study, authors actually found that those with chronic ankle instability had decreased sensation on the soles of their feet compared with healthy individuals. As methods of coping with ankle instability commonly include support devices, it’s possible that restoration of sensory receptors may never be addressed, or worse – blindfolded by layers of cushioning and support. It’s possible that this could create an unending cycle that presents as chronic ankle instability, repetitive sprain injuries, and other ankle/foot dysfunction.
Although support devices have their place in treatment, it is really important that people spend time out of their shoes to restore this normal feedback loop and ultimately regain healthy functional movement. This should be done in a safe manner; I’m not saying that everyone should become barefoot runners (I’ll save that topic for another day…). But for now, here are a couple ways that you can increase the amount of input to your feet:
So go ahead and kick off your shoes, get a massage, and give your feet some love – you might be surprised by what you find!