March 10, 2016
Dr. Justin Dean
Read more of what Dr.Dean is up to on his site – http://drjustindean.com/
If you quickly peruse popular strength training magazines, blogs and Vlogs (video blogs) it is common to see a majority of the content reference core and hip training. These areas are important to human function, but I would like to draw some attention to the body part we cover up, hide and neglect, despite it providing the evolutionary ability for upright locomotion, the foot.
Learning about training the hips and core in terms of endurance, strength, power and coordination are all extremely important, and should be implemented into training the foot for optimal performance. The purpose of this blog is to highlight the importance of how properly integrating the foot into training protocols will increase neural output (performance) of the entire locomotor system.
It takes roughly six weeks of training to make a change in connective tissue density, such as muscles and ligaments, yet any good coach can create performance improvements quickly using properly executed cues. This immediate increase in output (performance) is a great example of how quickly the brain can modify specific movement(s) via sensory input such as a verbal cue.
The foot, face and hands occupy a significant portion of real-estate in the brain designated to receiving, analyzing and interpreting sensory information as we interact with the environment around us, such as our feet on the ground. In short, with consistent sensory information being relayed to the brain through solid contact between the foot and the ground, the more power the brain will deliver to the ore and hips. The schematic of the homunculus demonstrates this concept.
The foot tripod is where the biomechanics and sensory input meet. From a biomechanics standpoint, there are three points in the foot that bear the most weight during upright and fixed activities, such as the deadlift and squat. These three areas include: the first metatarsal head, the fifth metatarsal head, and the heel (Figure 1). Together, these three points form a tripod. In order to create a stable base for the rest of the body to act from, each of these three points need to be firmly rooted in the ground prior to the start of a static activity or movement pattern such as the squat and/or deadlift.
The easiest and quickest way to assess overall foot function is with the single leg squat. There are several ways of performing this test. The single leg squat can be performed by stepping down from a box, either with the unsupported leg in front or behind the trunk. For simplicity sake, let’s place the uninvolved leg behind the person’s body and have them bend their standing knee to about 30 degrees (Figure 2).
When assessing foot function, the most common finding is the big toe will flex or bend, in an attempt to grip the ground, while the first metatarsal head oscillates up and down, to maintain contact with the ground.
Another common finding is for the fifth metatarsal head to struggle to stay firmly grounded. Both situations create upstream effects, including but not limited to, excessive knee valgus (knee towards midline), hip impingement and rounding (flexing) of the lumbar spine. All of these common motor control issues have been shown in the research to be potential mechanisms of injury and can decrease overall performance.
Integrating the foot into training
Most corrections come from increasing body awareness of the foot during movement. The key is to integrate the external (verbal) cues such as “imagine each point of the foot tripod you have eagle talons and try to grip the floor” (Figure 4).
Now dig those talons into the ground and twist outward to apply torque into the floor, without moving the feet. This can be effective in activating the external rotators such as the gluteal muscles. Maximal power production in the gluteal complex will help reduce the chance of “buckling” at the low back, hips or knees.
Verbal cues are great for most individuals, but some feet need to be bombarded with sensory information to the brain in order to “wake up the foot”. The exercise to the left demonstrates a band exercise based on principles from the Dynamic Neuromuscular Stabilization running course. I have found this particular band-assisted exercise to be very effective for teaching patients and athletes how to keep their first or fifth ray firmly rooted to the ground.
Dr. Justin Dean is a chiropractor practicing in Los Angeles, California