Do you want to move optimally, increase strength and decrease your injury potential? Start with your foundation: turn on your feet and optimize your soles. In order for the foot and consequently lower extremities (including the core musculature) to work properly, our brains need to ‘feel’ the ground. This is why the soles of our feet are jam packed with nerve endings and touch receptors (mechanorecptors). They create a sensory feedback loop between the brain and foot, driven by an estimated 200,000 nerve endings on each sole. Being barefoot stimulates the brain and wakes up innate sensations. According to Nigg and colleagues, these plantar aspect nerve endings are crucial for:
Joint protection
Ameliorating impact forces
Proper gait
Muscle rate coding, sequencing and activation
Navigating terrain
Like most other animals (try putting shoes on your cat or dog and see what happens- hilarity ensues) the human baby will reject footwear because she needs to feel the world with her tiny baby feet. Along with our lips and hands, the skin covering the sole of the foot is one of the most nerve-rich environments on the human body. Sadly, the typical chair-born sedentary modern human is all but destroying his sole(s). As infants, we all start off with sensitive soles but many of us have impaired our nerves over the years. Chronic shoe wearing, lack of movement on diverse terrains and general slothfulness are the main culprits compromising the neural activity in our feet. Let’s face it, many of us are walking around on dead soles.
Sensory information from Arnold’s soles is helping him produce more force
Wearing shoes will decrease blood flow and slow down or block information our brain needs regarding ground forces. The foot’s diminished ability to read the forces and angles on the ground results in faulty motor patterns and slow responses, leading to compensations and injuries. The small peripheral nerve endings covering the skin of the soles are adept at sensing vibrations, pressure, skin stretch and light touch. Larger diameter nerves tend to be slower and found primarily in the tendons and joint capsules. The small nerves enable a pre-active response to impact forces, providing the body with more time to efficiently adapt movement. Most shoes will scuttle the small nerve responses your brain craves and reroute feedback to the slower large nerves. The difference is mere milliseconds, which may not seem like a lot to us but is an eternity in the neural highway. This difference has been shown to cause slower responses and injury. Wearing shoes slows reaction times and decreases natural proprioception.
Factoid: As we age (around 40 years old) all of our motor and sensory nerves start to decline, affecting power output, balance and gait. Controlling one’s diet by specifically limiting sugar and spending more time barefoot can dampen some of this age-related neurodegeneration.
In the arena of sports and general athleticism, where proprioception is highly valued, participants will likely be barefoot or in minimal footwear; martial arts, dancing, boxing, fencing and gymnastics. An increasing number of athletes are moving toward the barefoot model, if not in the game, then at least during practice. Track teams, football and basketball players and even Cross-fitters are making the switch. Many NFL and NBA teams are now practicing and warming up while barefoot. Warming up barefoot before you put your sneakers on will help increase your stability, mobility and overall proprioception while decreasing your chances of injury. Win-Win!
Action Plan:
In order to revive your soles and get ground force information to your brain faster practice these four things:
Spend 5-10 minutes barefoot prior to your activity or game
Practice Janda’s Short Foot movement on 1 leg a few times a day
Spend some time barefoot walking on heterogeneous textures and terrains – walk on gravel!
Attempt to perform all lower body lifting sessions barefoot as much as possible
Walking, running, hiking and exercising barefoot will not only make your feet and core healthier it will also encourage brain neuroplasticity.
Reference:
Splichal E. (2014). Application of Barefoot Science in a Rehab Setting An Evidence-Based Approach. Presented as a seminar topic by Evidence Based Fitness Academy.
Cunningham et al. (2010). “The influence of foot posture on the cost of transport in humans”; Journal of Experimental Biology 213:790.
Robbins et al. (1993). “Protective sensation of the plantar surface of the foot”; Foot and Ankle 14:347.
Howell D. (2010). “The Barefoot Book: 50 Great Reasons to Kick off Your Shoes”; Hunter House Inc; p.31-43.
