Stress fractures are preventable in most cases, and the strategies that work best target the root causes: doing too much too fast, under-fueling your body, and neglecting recovery. About half of all stress fractures occur in the shinbone (tibia), with another 25% hitting the long bones of the foot (metatarsals). Runners, military recruits, and anyone ramping up physical activity are most at risk. Here’s how to keep your bones intact.
Build Training Volume Gradually
The single biggest modifiable risk factor for stress fractures is training load, specifically how quickly you increase it. Bone adapts to impact by remodeling itself, but that process takes weeks. When you pile on mileage or intensity faster than your skeleton can keep up, microdamage accumulates faster than it’s repaired.
The classic guideline is to increase weekly mileage by no more than 10% per week. That’s a reasonable starting point, but recent research suggests the length of your longest run matters even more than total weekly volume. A sudden jump in long-run distance is a larger risk factor for bone stress injuries than a modest bump in everyday miles. A practical framework: keep your weekly long run under 50% of your total mileage, limit long-run distance increases to about 10% per week, and avoid increasing both distance and intensity at the same time. Pushing harder and longer simultaneously is when injuries happen.
If you’re returning from time off, resist the urge to pick up where you left off. Your cardiovascular fitness declines slower than your bone’s tolerance for load. You might feel ready to run six miles, but your tibia isn’t. Back off to roughly 50% of your previous volume and rebuild from there.
Eat Enough to Match Your Activity
Undereating relative to your training demands is one of the most underappreciated causes of stress fractures. This condition, called Relative Energy Deficiency in Sport (RED-S), occurs when “energy in” consistently falls short of “energy out.” It doesn’t require a formal eating disorder. Skipping meals, cutting calories to lose weight during a training cycle, or simply not realizing how much fuel high-volume training demands can all create a deficit.
When your body runs on too little fuel, it starts rationing. Bone maintenance gets deprioritized. Insufficient energy intake leads to low bone mineral density, raising the risk of both stress fractures and, over time, osteoporosis. In younger athletes, chronic underfueling can prevent bones from ever reaching their peak density in the late 20s, shortening the window before age-related bone loss begins.
RED-S also disrupts hormones. In women, it causes irregular or absent periods. That matters for bones because estrogen is a key driver of bone mineral density. In men, it lowers testosterone and reduces libido. Other warning signs include persistent fatigue, frequent illness, slow recovery from workouts, mood changes, and declining performance despite consistent training. If several of these sound familiar, the issue may not be your training plan but your nutrition.
Prioritize Calcium and Vitamin D
Your bones need raw materials to repair the micro-stress that exercise creates. Calcium and vitamin D are the two most critical nutrients for that process. Most adults need around 1,000 mg of calcium daily (1,200 mg for women over 50), and 600 to 800 IU of vitamin D, though many sports medicine experts recommend higher vitamin D intake for athletes, particularly those training indoors or living in northern climates.
Dairy products, fortified plant milks, leafy greens, and canned fish with bones are reliable calcium sources. For vitamin D, sunlight exposure helps, but food sources like fatty fish, egg yolks, and fortified foods fill in the gaps. If you suspect you’re falling short, a simple blood test can check your vitamin D levels, and supplementation is straightforward if needed.
Get More Than 8 Hours of Sleep
Sleep is when your body does its deepest repair work, and skimping on it raises injury risk substantially. A study of 340 adolescent elite athletes found that those averaging more than 8 hours of sleep on weekdays had 61% lower odds of sustaining a new injury compared to those sleeping less. That’s not a small effect. If you’re training hard and sleeping six or seven hours, you’re undermining your body’s ability to keep up with the damage you’re creating.
Quality matters alongside quantity. Consistent sleep and wake times, a cool and dark room, and limiting screen exposure before bed all contribute to the kind of deep, restorative sleep that supports bone remodeling. For athletes in heavy training blocks, naps can supplement nighttime sleep, but they don’t fully replace a short night.
Strengthen the Muscles Around Vulnerable Bones
Strong muscles absorb impact before it reaches bone. When your calf muscles fatigue during a long run, for example, more of each foot strike transfers directly to the tibia. That’s one reason stress fractures often show up late in training cycles or during high-mileage weeks, when muscles are too tired to do their shock-absorbing job.
Targeted strength training reduces this risk. For runners, calf raises, single-leg squats, hip strengthening exercises, and foot intrinsic work all help distribute forces more evenly. Two to three sessions per week is enough to see meaningful gains without adding excessive fatigue. Plyometric exercises like box jumps and hopping drills also stimulate bone to become denser, but introduce them gradually, as they carry their own injury risk if you jump in too aggressively.
Vary Your Training Surfaces and Footwear
Running exclusively on concrete applies repetitive, identical stress to the same bones in the same way, mile after mile. Mixing in softer surfaces like trails, grass, or tracks changes the loading pattern and gives heavily stressed areas a partial break. You don’t need to abandon roads entirely. Even one or two runs per week on a different surface helps.
Worn-out shoes lose their ability to cushion impact. Most running shoes lose meaningful shock absorption between 300 and 500 miles, though this varies by shoe construction and your body weight. If you can’t remember when you bought your current pair, it’s probably time to rotate in a new one. Alternating between two pairs extends the life of both and gives the foam time to decompress between runs.
Be Cautious With Anti-Inflammatory Painkillers
If you’re dealing with shin pain or foot soreness during training, reaching for ibuprofen or naproxen might seem logical. But common anti-inflammatory painkillers (NSAIDs) interfere with the very process your bones use to heal. Bone repair depends on an inflammatory response driven by specific enzymes, and NSAIDs work by suppressing those same enzymes.
A meta-analysis found that using NSAIDs after a fracture roughly doubled the odds of adverse bone healing events in adults. That’s a significant concern not only for recovering from a stress fracture but also for managing pain during heavy training, when your bones are actively remodeling. Acetaminophen (Tylenol) offers pain relief without the same interference with bone healing, making it a better option when you need something to take the edge off. Persistent bone pain during training, though, is a signal to rest and get evaluated rather than to medicate and push through.
Recognize Early Warning Signs
Stress fractures rarely appear without warning. They typically begin as a dull, localized ache that shows up during activity and fades with rest. Over days to weeks, the pain starts earlier in your workout, lingers longer afterward, and eventually hurts during normal walking or even at rest. Pressing on the sore spot usually produces sharp, pinpoint tenderness directly over bone rather than the broader soreness you’d feel with a muscle issue.
The tibia (inner shin), the top of the foot (metatarsals), the outer lower leg (fibula, about 10% of cases), and less commonly the thighbone (femur, roughly 5%) are the most frequent locations. If you notice bone-specific pain that worsens with activity over several days, reducing your training load immediately gives you the best chance of catching it early, when a few weeks of modified activity may be all you need rather than months on crutches.