If you are a field or court athlete, the part of your body that interacts with the ground 99.9% of the time is your feet. The strength and power developed in your legs and hips is transferred into the ground through your feet and ankles. When your foot hits the ground the position and function of the foot/arch directly impacts the position and function of the joints up the kinetic chain.
The kinetic chain is the link created between the joints of our body by the bones, muscles, tendons, ligaments, fascia, and other soft tissue. When your foot is on the ground, movement at one joint impacts the position of the other joints in the kinetic chain.
In the above image, starting from the ground up, the arch of the foot drops (over pronates) and results in the knee internally rotating, the pelvis tilting, and the opposite shoulder dropping. Each of these positional changes leads to suboptimal force absorption, storage, transfer of energy, and force production. This occurs as a result of the above shown "reverse waterfall" of joint compensations that load the kinetic chain sub optimally from the ground up. This can lead to a wide range of chronic and/or acute injury and decrease overall athletic output. If the foot and ankle aren't performing optimally, then you cannot express the power and strength from your quads, hamstrings, glutes, etc. that you work so hard to develop.
When the foot interacts with the ground optimally the rest of the kinetic chain has a much better chance of organizing itself into positions that allow for higher levels of athletic expression and decrease injury risk overall.
Now that we have covered the roll of the foot in the kinetic chain and athletic output, lets briefly talk about the structure and function of the foot. The foot is made up of three arches, the medial longitudinal arch, the lateral longitudinal arch, and the transverse arch(es). These arches, and the foot as a whole, are stable (or ridged) during the foot-strike and push-off phases of gate. In between these phases of gate, at mid-stance, the foot must become mobile in order to attenuate loads. The deformation (pronation) of the medial longitudinal arch during mid-stance creates the potential for the foot (and in athletics, other parts of the kinetic chain) to store and release elastic energy. However, the foot (specifically the medial longitudinal arch) can deform too much during the mid-stance phase leading to hyper pronation. Hyper pronation results in decreased power production, inefficient force transfer during running/sprinting, and inefficient foot stiffness. The big takeaway for athletes and coaches is that a weak foot, one that hyper pronates during running/sprinting, reduces the force produced by the plantar flexors, thus reducing the overall propulsive effect of each stride (not good!)
The obvious follow up question is "what can I do to improve my foot strength to increase my athleticism?". Strengthening the intrinsic foot muscles is the key. The intrinsic foot muscles play an important role in providing flexibility, stability, and shock absorption for the foot but are often inhibited (don't work as well as they should) from years of cramming our feet into shoes. Shoes can inhibit these muscles because when your foot is inside of a shoe the intrinsic foot muscles do not need to work as hard as a result of the support provided by the shoe and the lack of space for our toes to move independently. Our goal with the following Intrinsic Foot Strength Series will be to counteract this weaking of the foot musculature and improve your overall durability and athletic potential!
Below is a video that takes you through a few different drills to increase the strength of the intrinsic foot muscles. There is also a pdf and image of the program for your reference. Doing these drills daily can go a long way in making you feel stronger, faster, more explosive, and just plain dangerous on the field or court!
Intrinsic Foot Strength Series
