by Russ Ebbets, DC
A stress fracture is a nuisance injury for a runner. For the running population, stress fractures are most often found in the foot but can also be seen in the shin, thigh bone, pelvis, and spine. Causes include mechanical forces or metabolic issues that the body cannot manage. Any number of factors contribute to the development of this problem, with most of them preventable.
Stress fractures seem to develop spontaneously, unlike a compound fracture (a broken bone pierces the skin) or a comminuted fracture (a broken bone shatters into two or more pieces). The foot usually begins to hurt after a run, and in the days that follow, the pain continues with running. A stress fracture is not the result of one memorable twist or turn, click or pop but rather the result of repeated microtraumas that cause tissue failure.
Mechanical stress fractures result from too much force, too much frequency, or too long a duration. Whether it is one of these factors, a combination, or all three, there is tissue failure, and the bone develops tiny, yet nonetheless painful, cracks.
The metatarsals are the long slender bones that constitute one-third the length of the foot. These forefoot bones are ten times more likely to develop stress fractures than other areas of the foot (Figure 1). They are under the greatest stress at toe-off, and lesser stresses as the foot rolls through the ground contact cycle of heel strike, midstance and toe-off. If one is a “toe-striker” and runs on the forefoot, this can create another high-stress situation that can be a causative factor.
Two common contributing factors include shoes and surfaces. Poorly constructed shoes or worn-out shoes with an “exhausted” mid-sole offer little support and protection for the thousands of ground contacts the foot sustains with daily and weekly training. Hard, level surfaces with little “give” also present a potential hazard. Most masters athletes appreciate the give of a golf course or tanbark trail and the reduction of pounding the feet and legs would take.
Weak feet can also play a role in the development of foot stress fractures. A poorly conditioned or poorly coordinated foot that slaps the ground with each foot strike elevates ground contact forces with the thousands of daily foot strikes. Excessive pronation or flat feet offer reduced shock absorption and subject the foot to excessive strains and tissue failure.
Training frequently plays a role in the development of stress fractures. Rapidly increasing one’s volume (how much) or intensity (how hard one trains) without adequate rest and regeneration can place unrelenting stresses on the body that can result in breakdown. Increased volumes and intensities are a variation of the force-frequency and duration mentioned above. This underscores the importance of gradually increasing one’s training loads and keeping one’s motivation “to do more” in check.
Lastly, stress fractures can result from metabolic issues in the body. Attention to one’s diet plays a critical role in performance-based sports. A diet of highly processed foods with little nutritional value does not allow the body the nutrients to repair the damage of high-intensity training. Complicating this factor are eating disorders and crash diet regimens that stress the metabolic functions (hormones, enzymes, upset of the acid-base balance) of the body, resulting in a compromised repair and regeneration that can affect the skeletal structure and ultimately performance.
Diagnosis of a stress fracture can begin with the complaint of a “vague pain” when weight-bearing in an area traceable with a finger. The use of a 128 Hz tuning fork may be productive, as the tuning fork’s vibration shakes the disrupted tissue and can pinpoint the area of pain. Traditional x-rays are usually not productive for an acute situation (a pain that is less than a week old). The problem with an x-ray for an acute stress fracture is the absence of a dramatic break seen with a compound fracture, and the x-ray may appear to be “normal.”
An x-ray taken 10-14 days after the onset of pain may be more productive as there will be a visible, cloudy outline known as a callous formation that would be indicative of bone healing (Figure 2). Bone scans are more expensive but show early on increased metabolic activity (also known as “hot spots”) where the bone is trying to heal itself, which will be visible in the area of injury.
Treatment involves a heavy dose of the dreaded rest, especially from running. I do not doubt that there are runners who have “run through” a stress fracture. But, in my world, that will only prolong the injury and probably injure “something” on the other leg with all the limping. Temporary use of a “walking boot” may stabilize the area and jump-start the healing process. Intelligent use of cross-training, resistance work, water running, or cycling (if there is not too great a pressure on the foot) can allow one to maintain a level of fitness so that when the stress fracture heals, one does not have to resume training at square one.
Additionally, one might consider nutritional supplementation to aid recovery. Taking some extra calcium and vitamin D can help with the overall repair. One should be cautioned about taking too much calcium as it can cause constipation and make the whole process counterproductive. If one’s dietary norm is highly processed or fried foods, this may be an opportunity to gain some new, better eating habits.
Hopefully, recovery makes one older and wiser. Prevention comes with attention to several areas. We have noted the import of training surfaces, shoe inspection, training volumes and intensities, and nutritional supplementation. One might consider using a shoe insert or orthotic that will support the foot and help dissipate the shock of ground contact. Also recommended would be the six foot drills (YouTube – The Six Foot Drills - FLPKtv) that, if used consistently, will condition the small intrinsic muscles of the foot to better handle the challenges of continued training.
Stress fractures to the thigh, pelvis, and spine are more problematic. Although rarer than foot stress fractures, they are not uncommon. The more troubling issue with these types of stress fractures is that they are usually the result of a more serious behavioral problem. Obsessive training habits combined with long-term poor dietary practices are a problematic combination. The long-term lack of proper nutrition combined with excessive training promote the downward spiral of chronic overtraining. Poor performance, illness, and injury (i.e., stress fractures) are often the result. The athlete has lost control of goal-oriented training and set his or her efforts on an unrealistic path. The body does have its limits.
On the good news side, realize that a stress fracture in the foot usually happens to highly- motivated athletes. The couch potato does not suffer from this injury. And while we can lament that this injury “shouldn’t” occur, realize that it can, especially as one approaches that fine line between enough training and too much training. Unfortunately, stress fractures usually happen at an inopportune time, when a season is winding down, and one is in peak physical condition banging out quality workout after quality workout. Healthy dietary habits, healthy foot habits, and greater attention to what is going on with training can help avoid this nuisance injury.
Russ Ebbets, DC is a USATF Level 3 Coach and lectures nationally on sport and health-related topics. He serves as editor of Track Coach, the technical journal for USATF. He is the author of the novel Supernova on the famed running program at Villanova University and the sequel Time and Chance. His most recent book, A Runner’s Guide, a collection of training tips and running articles, was a 2019 Track and Field Writers of America Book of the Year finalist. He can be contacted at email@example.com.