The Foot Tripod

The foot is a very complex structure that is suited to handle several key tasks involving human movement. With 28 bones, articulating joints between each of those bones, and many muscles acting on those bones and joints, the foot can be a bit overwhelming when attempting to understand its intricacies in movement.

When I work with clients, the feet are an area I am always paying attention to. Some of the most common dysfunctions and symptomatic presentations throughout the body often involve compromised function of the feet. If you think about how often we use our feet when we move, most of the time we are on our feet. Standing in line at the grocery store. Walking around the house cleaning. Commuting to work on foot. Going for a run. Hiking. Particularly with traditional strength training exercises like deadlifts, squats, and lunges, the feet are the foundation.

In my estimation, the feet have several major functions. First, the feet provide the foundation for gait. In gait, the foot needs to dynamically stabilize and oscillate between pronation and supination to feed into the kinetic chains upstream. Secondly, the feet are rich with receptors providing copious amounts of feedback about body position, the surfaces we are walking on, balance, etc. Lastly, the foot often acts as a tripod to provide isometric stability during many different closed-chain exercises, particularly those that are common within traditional strength training methodologies like squatting, deadlifting ,lunging, etc.

For the purposes of this article, we are focusing on the tripod function of the foot, briefly reviewing the anatomy, the role the foot tripod plays in providing a stable foundation for strength training, and some ways to improve the function of our foot tripod through exercises and drills.

Anatomy of the Tripod Foot

Let’s start by talking about the three-points that make up the foot tripod. First, we have the calcaneus (heel) as the first contact point. The medial contact point of the tripod is the first MTP joint or the first metatarsal head (ball of the foot). The lateral contact point is the head of the fifth MTP joint (base of the pinky toe). See the points highlighted below.

(Picture from Tony Gentilcore’s blog – Tony’s is an excellent blog to follow.)

Easy enough to conceptualize and visualize, right? Understanding the structure of the tripod is important. We need each of these three points to be able to maintain contact with the ground. If one point cannot engage with the floor, then the rest of structure above (lower leg, knee, upper leg, hip) will have its alignment and function compromised during movement. For example, an inability to load the medial contact point typically leads to excessive pronation, which often creates a cascade of rotational compensation in the knee, hip, and pelvis.

In order to understand how to ensure each of these points is functioning to promote a strong tripod and stable foot, we need to also understand the primary muscles involved. These are:

  • Posterior Tibialis
  • Abductor Hallucis
  • Flexor Hallucis Longus
  • Extensor Hallucis Brevis

While there are more than just 4 muscles that have a direct impact on the structural integrity of the foot tripod, these are the main players. The posterior tibialis helps to supinate (think – “turn in”) the foot, which lifts the arch, facilitating inversion of the ankle. The abductor hallucis is key in controlling the “gripping” or “reaching” movement of the big toe through the midfoot. The extensor hallucis brevis is important in how it affects the first MTP joint, allowing the ball of the foot to settle onto the ground instead of the pad of the big toe simply just pressing into the floor. The flexor hallucis brevis runs through the sesamoid bones (for mechanical advantage) and ultimately helps the 1st metatarsal (big toe) to press down and engage with the floor, similarly to the abductor hallucis.

Each of these muscles help provide structural integrity of the foot arch. Being able to have a normal foot arch is paramount for having a stable and functional foot tripod. If there are dysfunctional relationships between the ankle, rearfoot, midfoot, forefoot, or toes, our arch and thus our tripod will function less than optimally.

Tripod Foot During Training

Other than low-back pain, knee pain might be the most common pain out there, for both sedentary folks and high level athletes alike. Not taking into consideration acute trauma to the knee, such as ACL sprains or meniscus tears, knee pain is most often a product of mechanical stress created by dysfunction in the feet or hips. Not spending enough time on our feet, coupled with the fact that the time we do spend on our feet is typically in cushioned footwear, is not a recipe for healthy and functional feet. When someone comes to see me with knee pain, 8 out of 10 times, improving their foot function resolves their knee issues.

When it comes to understanding the feet from a strength training perspective, here a few key principles to think about:

  • Inability to bear weight on outside of the foot will emphasize the medial quads, hamstrings, calves, and adductors.
  • Inability to bear weight on inside of the foot will emphasize the lateral quads, hamstrings, and calves.
  • Inability to load the forefoot will often lead to synergistic dominance of the toe extensors and lumbar erectors.
  • Inability to load the rearfoot (heel) will often lead to synergistic dominance of the distal quads and adductors.
  • An unstable foot tripod will lead to an inability to load at least one part of the foot.

For the sake of simplicity (foot mechanics are anything but simple), we are referring mostly to closed-chain (foot is in contact with the ground or a platform) exercises like squats, deadlifts, and lunges. An inability to load any given part of the foot is a problem when you’re working with appreciable loads. If you can’t efficiently distribute load through the whole foot, you will inevitably compensate somewhere further up in the kinetic chains. As previously mentioned, suboptimal compensation usually leads to mechanical stress on adjacent structures like the knees, hips, pelvis, and lower spine. The key to a functional capacity for lower body strength training starts with the foot.

Establishing a functional foot tripod is the first step in restoring and maintaining healthy feet. After we learn how to create isometric stability in our feet via our tripod, we can then branch out and start to explore the dynamic stability of our feet on the pronation-supination continuum. But we will save that for another day.

Strategies to Improve Function the Tripod Foot

Try this: Stand hip width apart with your glutes engaged so your pelvis is in neutral alignment, and lift just your toes off the ground. Can you feel the 2 forefoot tripod points? How about if you start to bend at the knees and hips to initiate a squat?

If not, there is a compromise in your ability to load either the inside of the outside of the foot properly. This will lead to inefficient loading in the primary leg and hip muscles.

In order to restore our foot tripod we need to improve mobility within the bones and joints of the foot. If the bones can’t move, it’s typically indicative that they do not have the capacity for load. If either the structural integrity of the joint, or the muscular support required to stabilize the joint during any given movement are not functioning optimally, the nervous system often creates compression in the joint in an attempt to create stability. This is a less than ideal compensation strategy. While it makes the joint more stable, it also decreases joint space, increases mechanical stress in the joint, and creates short-circuiting of the muscles (tight, painful, weak) that act on that joint.

In my experience, the quickest and most effective way to restore mobility in a joint is to specifically assess and correct neurological compensation via specific manual therapy techniques like P-DTR. Manual adjustments performed by a qualified professional can sometimes be helpful and necessary. Problem is that they often don’t stick. The way to make manual adjustments stick is to reinforce and integrate the adjustments or mobilizations with movement.

One of the best self-administered ways of improving joint mobility over time is through gentle joint flossing drills. By progressively subjecting the joints to mobilization techniques that allow the joints and muscles to adapt over time, both the structure and nervous system will process and manage the movements better.

Three key areas to ensure have the requisite bone-on-bone mobility are the calcaneus, cuboid, and navicular. Each of these midfoot bones’ ability to load is paramount for foot tripod function. Here are three drills that I have had tremendous success utilizing with myself and with clients to help restore mobility in the calcaneus, cuboid, and navicular bones of the feet.

Utilizing these drills to “wake up” the foot and get the joints moving more freely is an effective first step in improving our foot tripod. After we mobilize the feet, we then need to integrate the feet with the ankles. Here’s one of many drills I like to work on this:

From here, there are no shortage of other drills you can use to specifically address whatever deficiencies your feet might have. To start, I suggest trying out the above drills, and then training bearfoot more often, especially on your lower body focused training days.

The feet can be understood and broken down so many different ways. Hopefully this perspective is helpful in better understanding the foot tripod. Plenty more information on the feet is in the works.

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