As runners, our feet take a beating. Foot pain can greatly impact a runner’s ability to train and race to your potential. Running places 2.5 to 5.0 times the weight of the body through each foot strike. Foot pain, however, does not have to be synonymous with distance running. This month I will explain foot anatomy, preventing toe nail loss, ingrown toe nail prevention, and stress fractures. In next month’s article, I will discuss plantar fasciitis.

FOOT ANATOMY:       imgres.142302
Understanding the foot and how to avoid a few common foot injuries will enable runners to achieve training and racing goals. The human foot contains 26 bones (28 if you count the two floating sesmoid bones on each foot). The bones of the foot form three distinct structural and functional units. The rear foot is made up of the large calcaneus and talus. The rear foot is designed for weight bearing and articulates with the lower leg bones (tibia, fibula). The mid foot is made up of the navicular, talus, and cuneiform bones. The mid foot has a dual role. It absorbs shock during weight bearing and forms the stability we rely on (the arch) when pushing off to initiate the next step. The fore foot is made up of the five metatarsal bones and 14 bones in our toes (phalanges).

Observation of the bone structure of the foot explains why our feet are so uniquely shaped. Foot function is responsible for the unique shape of each bone within the foot. The wedge-shaped mid foot bones allow shock absorption during pronation (weight bearing acceptance), but with muscle contraction the flexible wedge becomes a rigid supporting structure which drives body propulsion. In contrast, the stout calcaneus and talus bones are weight bearing structures. Even though mid foot and fore foot running has been shown to be more efficient and decrease running injuries, humans heel strike when we walk. Finally, the fore foot is the region of the foot which allows us to “feel” the trail or road when we run. Balance, agility, and proprioception are duties of the fore foot.

The skeletal anatomy of the foot must be combined with the stability and mobility provided by our connective tissue (ligaments, tendons, fascia) and muscular tissue (Intrinsic: within the foot; Extrinsic: lower leg muscles). The ability to react to uneven surfaces in a fraction of a second and rhythmically run without active concentration is made possible by the neuromuscular function of the foot. Continuous, two-way nerve messages to and from the foot to the spinal cord and brain result in split-second shock absorption, foot work finesse, and propulsion power.

Trail runners are particularly susceptible to toe nail impact injuries. Striking rocks with the front of your shoe is often unavoidable and sure to traumatize toe nails. Working on foot placement and agility over rocky surfaces may reduce the frequency of toe nail trauma due to striking rocks head on. Downhill running (especially fast downhill running) can lead to toe nail trauma as the foot shifts forward in your shoe. The nail root, located at the base of the toe nail, becomes inflamed during to impact. If impact is sufficient, the nail may actually avulse from the nail bed, leading to eventual nail loss. Do not attempt to remove a traumatized toe nail as it will shed itself once a new nail is sufficiently established beneath the old nail. Understanding the foot and how to avoid a few common foot injuries will enable runners to achieve training and racing goals.

Trimming your toe nails (discussed below under Ingrown Toe Nails) properly will also decrease trauma to the nail matrix and nail root. A shoe with a wide toe-box may reduce the risk of toe impact against the front of the shoe, but proper lacing must be utilized as well. Be sure our mid-foot is secure by proper lacing while allowing your toe the room it needs to spread and absorb impact. The Runners Edge staff can help match your running style and foot shape to a shoe which will minimize trauma to your toe nails.

A less common but equally painful running-related to issue are ingrown toe nails. The most common cause of ingrown toe nails is improper trimming of toe nails. Often runners believe toe

nails must be as short as possible to decrease toe nail trauma and loss. Proper trimming, however, is more important than toe nail length. Remember, your toe nails are designed to protect your toe, so cutting them super short exposes the ends of your toes to impact, trauma, and blisters. Proper toe nail trimming involves a flattened toe nail end. Rounding off the toe nail when trimming the nail actually increases lateral toe nail growth and can lead to the formation of ingrown toe nails. Not only can they be painful, but severely ingrown toe nails may become infected and require medical attention.

Excessive impact can break down the structural integrity of the foot (joints, connective tissue, and muscular support).

The greatest enemy of the foot, however, is torsion. Bones, joints, and connective tissue function properly when movement is through designated planes. Torsion through a joint or bone, however, greatly increases its chance of fatigue and failure. Stress fractures are often the result of excessive torsion through a bone secondary to inadequate stability (muscle weakness or lack of connective tissue tensile strength).

To prevent structural failure and subsequent injury in the foot, runners must regularly address foot and ankle strength, proper joint mobility, and allow for tissue recovery. The experts at Sapphire Physical Therapy can evaluate your running gait, detect any form or strength issues, and develop a foot injury prevention and treatment program to meet your individual needs. Call Sapphire Physical Therapy or see learn more at and don’t let your feet keep you from meeting your running goals.

John Fiore, PT
Sapphire PT