Understanding Foot and Ankle Function: A Comprehensive Guide for Athletes
- Danny Foley- MS, CSCS,D*
- Oct 6, 2025
- 8 min read
Updated: Dec 2, 2025
The Importance of Foot and Ankle Function in High-Performance Training
Foot and ankle function is often overlooked in high-performance training. However, these components are crucial for athletic success. The foot is not merely a passive structure; it is a highly dexterous and integral part of human movement. It serves as the first point of contact with the ground during sprinting, changing direction, and various sport-specific actions. The foot-ankle-lower leg complex plays a vital role in how forces are experienced and produced throughout the body.
The foot is an engineering marvel, comprising 26 bones, over 100 muscles, and intricate networks of connective tissue and sensory receptors. With so many moving parts, compensations are inevitable, and these compensations can have significant implications. While structure may predispose function, it does not determine it. No foot posture or shape is inherently "good" or "bad" in isolation. What truly matters is adaptability—the foot's ability to stiffen, flex, or attenuate force based on demand (Burns et al., 2005).
There is a clear correlation between foot-lower leg function and injury frequency and severity. In my experience working with youth athletes, I estimate that 80% of my workload involves foot, ankle, and lower leg injuries. Common issues like stress fractures, chronic ankle sprains, plantar fasciitis, and turf toe are particularly problematic among young athletes.
To address this, I aim to share insights and information about these injuries and strategies to reduce their frequency and severity.
In this article, we’ll cover:
The mechanical relationship between arch height and ankle stability
Common drivers of foot, ankle, and lower-leg impairment and injury
How body position and BOS/COM alignment change foot mechanics
Note: If you missed it, check out this **foot-ankle series I’ve been running on IG. This will provide deeper context and understanding of the primary points in this articl
Structural, Functional, and Technical Components of Foot
The SFT framework, adopted from Stu & ALTIS, is a valuable tool for assessments and overall training approaches. We can also apply this framework to the foot-ankle complex for a more focused view.
Many coaches and practitioners get caught up in optimizing a specific quality, often missing the bigger picture. Well-meaning coaches tend to focus on isolated mechanics—like tibial rotation, arch height, or calcaneal position—and draw hard conclusions about injury risk or performance. This tendency is particularly prevalent when it comes to the foot and lower leg.
However, if you watch any game for just ten minutes, you'll see a wide variety of foot shapes, positions, and patterns. Foot structure is important, but analyzing it in isolation does not provide meaningful insights. While isolated testing and strength assessments for the foot-ankle (e.g., Natera Ankle ISO) can be valuable, they do not tell the whole story. Numerous examples of foot position during running mechanics defy conventional biomechanical beliefs (check out this Gout Gout video).
The key is to appreciate the structural, functional, and technical components and use your coaching acumen to determine their relative significance. When it comes to injury, virtually everything could be a factor, but not everything matters. For the foot-ankle complex, structural predispositions—such as arch shape, joint laxity, and fascial stiffness—interact with an athlete's history (injury, training, sport). The combination of structural and functional factors informs our coaching input for technical demands. Structural features lay the groundwork, but functional and technical layers dictate how that groundwork performs under load (Hintermann, B. 1998).
An Example Between Arch Height and Ankle Stability (Structural Factors)
Historically, arch height has been viewed as a villain in foot structure. The medial longitudinal arch is a critical structure, functioning like a spring—it compresses, recoils, and adapts. Instead of labeling athletes as having "flat" or "high" arches, we should discern how this arch functions in context. Arch height alone doesn't provide much insight; what matters is the complementary foot mechanics and adaptability under various stressors.
High arches (cavus): Rigid, limited pronation, poor shock absorption, lateral overload (ATFL, peroneals).
Low arches (planus): Mobile, prone to collapse, medial overload (plantar fascia, tib post, spring ligament).
An important mechanical relationship exists between arch height and ankle stability. The medial plantar arch is a primary force transmitter, playing a massive role in how forces are attenuated and transferred from the ground. Athletes with higher arches may overwork the lateral ankle compartment as a force transmitter. Conversely, those with flatter arches may overwork the medial ankle compartment and posterior tibialis as stabilizers and force transmitters.
Both high and low arches can contribute to chronic ankle instability and balance deficits compared to "normal" arches (Zhang et al., 2023; Lin et al., 2023). There is a mechanical sweet spot where the arch is adaptable; being too flat or too rigid can lead to problems. The goal is not to have a "big arch" or "small arch," but to achieve responsive modulation—the ability to stiffen when needed and yield when necessary. When the arch collapses, the entire foot unlocks, leading to subtalar joint shifts, medial talus drops, and tibial internal rotation—all of which compromise lateral stability and load the ATFL. Conversely, if the foot never pronates, all shock and angular demand funnel into the ankle joint, Achilles, and plantar fascia. Too much mobility or rigidity can lead to performance leaks and increased injury risk.
For example, consider an athlete with extremely flat arches and significant navicular drop. This foot structure often presents with considerable tension in the medial arch and lateral ankle ligaments (due to increased resting eversion). Conversely, we may observe tautness in the posterior tibialis and potentially the lateral plantar arch.
If we don't intervene, every time this athlete's foot strikes the ground—especially under high force and velocity conditions—they will continue to stiffen the medial arch and lateral ankle ligaments while simultaneously putting the posterior tibialis, lateral plantar arch, and medial ankle ligaments at risk. The forces experienced during ground contact will transmit through tissues that are already stiff and strong, creating a path of least resistance. These scenarios set the stage for common overuse injuries, such as plantar fasciitis, turf toe, and, in this case, medial foot stress fractures.
Common Drivers of Foot/Ankle Dysfunction
Limitations in foot range of motion, stability, or compliance are never localized; the stress reverberates up into the knees, hips, and even the lumbar spine (Zhou et al., 2024). So, what should we emphasize to understand injury risk? While no program or preventative measures can eliminate all risk, we can adopt strategies to reduce the probability of injuries. Here are the "big rock" criteria I've observed:
Gross ROM deficits → Limited dorsiflexion and incomplete plantarflexion, along with the ratio between the two, are central factors. Restricted ankle dorsiflexion drives compensation up the chain (Houck et al., 2015). Additionally, foot pronation/eversion, supination/inversion, and tibial inversion/eversion are essential for complementing larger actions of dorsiflexion and plantarflexion.
- Goals: Aim for roughly 15-25° of dorsiflexion, 30-40° of plantarflexion, and maintain approximately a 1:2 ratio of DF:PF on the same foot, with less than 10° of left/right asymmetry.
Frontal/transverse mismanagement → Over-pronation (medial overload), rigid supination (lateral overload), and tibial IR/ER restrictions.
- Pronation and supination are challenging to measure, and I do not personally try to quantify these or tibial IR/ER. However, a keen coach's eye for how these motions occur independently and integrate into global patterns should be a priority.
Base of Support (BOS) Relative to Center of Mass (COM) → Position determines pressure, and pressure determines force.
- The positioning of the foot (BOS), how it is pressurized (COP), and its relation to the body’s center of mass (COM) collectively determine how forces are sequenced up the chain.
Midfoot/arch integrity → Weak posterior tibialis, poor midfoot stiffness, and arch collapse under load.
- When athletes lack or lose midfoot integrity, it triggers a cascade of potential aberrant patterns. Midfoot stiffness is especially critical during high-velocity actions, particularly at toe-off and during cutting actions. The primary structure of interest here is the posterior tibialis.
Sensory/proprioceptive gaps → Loss of ground feel, reduced plantar sensitivity, and slower reactions to environmental demands.
- "Our ability to detect creates the opportunity to respond." Poor proprioceptive acuity at the feet increases strain on surrounding structures.
Incomplete or weak Windlass mechanism → Limited big toe extension, excessive tension through the medial plantar arch, and calcaneal instability.
The big rocks—dorsiflexion, plantarflexion, pronation/supination, and tibial rotation—play fundamental roles in subtalar glide and mechanics. A locked subtalar joint alters calcaneal position, directly impacting stress on the plantar fascia, Achilles tendon, and midfoot connective tissue. Impairments or undue foot compensations in these patterns ultimately compromise the windlass mechanism and the principles of force following stiffness.
Force Follows Stiffness
An essential consideration is understanding how forces are transmitted and encountered at the foot. "Force follows stiffness" is a central heuristic for how I view the onset of soft tissue injuries, particularly concerning the foot. This concept is frequently discussed by Keith Barr, especially regarding stress shielding.
Stress shielding is a mechanical phenomenon where the body protects or guards damaged areas by routing mechanical forces through surrounding structures. While this protective mechanism is beneficial for survival, it can have consequences in a performance context. At the foot and ankle, it is crucial to recognize the differences in stiffness across foot structures, such as the medial versus lateral plantar arches. When there are dramatic differences in stiffness between these structures, athletes are at a higher risk of injury. If we do not intervene appropriately in training, what is already stiff and strong will only become stiffer and stronger, while what is compliant and weak will continue to weaken. The greater the disparity between strong and weak structures, the higher the risk of injury.
We need stiffness in the foot-ankle complex. Over-mobilizing can be just as detrimental to foot function and health as being overly stiff or rigid. Ultimately, it comes down to thresholds and proportionality between structures, rather than simply labeling stiffness as good and compliance as bad. In practice, many programs provide generic "heel raises" or baseless mobility drills for calves, ankles, and feet. However, the foot must be trained to attenuate (eccentric), stabilize (isometric), accommodate (oscillation), and produce (concentric) across angles of dorsiflexion, plantarflexion, inversion, and eversion.
Conclusion
The foot is a paradox: rigid yet mobile, simple at first glance but incredibly complex under force. Neglecting this complexity in training can leave performance progress on the table and, at worst, lead to recurring sprains, tendon issues, and stress fractures. Managing and monitoring overall workload—intensities, cutting, and hard braking—along with implementing specific training protocols for foot and ankle mechanics is essential for addressing chronic foot pain and problems (Lin et al., 2023). The foot-ankle complex is vital for sport performance, and we must develop proficiency as a spring, brace, and lever. Strong feet do not happen by accident; they are built—one position, one bias, one rep at a time.
References
Burns, J., Crosbie, J., Hunt, A., & Ouvrier, R. (2005). The effect of pes cavus on foot pain and plantar pressure. Clinical Biomechanics, 20(9), 877–882.
Hintermann, B., & Nigg, B. M. (1998). Pronation in runners: Implications for injuries. Sports Medicine, 26(3), 169–176.
Houck, J. R., et al. (2015). Effect of ankle dorsiflexion range of motion on lower extremity kinematics and kinetics during functional tasks. Journal of Athletic Training, 50(3), 311–319.
Lee, D. H., et al. (2016). The effects of intrinsic foot muscle strengthening exercises on medial longitudinal arch morphology and function. Physical Therapy Rehabilitation Science, 5(2), 78–85.
Lin, C. I., et al. (2023). Postural control in individuals with chronic ankle instability: A systematic review and meta-analysis. Journal of Sport Rehabilitation, 32(6), 572–584.
Mulligan, E. P., & Cook, P. G. (2013). Effect of plantarflexion and dorsiflexion wedge conditions on Achilles tendon load during gait. Journal of Orthopaedic & Sports Physical Therapy, 43(3), 167–174.
Zhang, S. N., et al. (2023). Effects of high-arch and flat foot deformities on postural control: A systematic review and meta-analysis. Gait & Posture, 104, 144–154.
Zhou, Y., et al. (2024). Acute restriction of ankle dorsiflexion alters knee and hip joint motion and neuromuscular control during squatting. Journal of Biomechanics, 160, 111049.
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