Copyright (c) 2010 Benjamin Marble

Have you ever seen one of those machines that test the strength of different materials? You stick a concrete block or an iron beam or a china cup on the bottom half, and then turn it on. The top half of the machine descends, touches the object, and puts more and more pressure on it until the cup shatters, the iron beam twists, or the concrete block cracks and splinters, littering the room with bits of shrapnel.

Hate to break it to you, but you're kind of like that machine. And your bones? They're the material being tested, particularly the bones in your foot. Every time you put weight on your feet, you're putting pressure on your bones. And, while bones are pretty darn good at holding you up (that's what they're there for, after all), they can crack under pressure if it's great or consistent enough. These breaks in the bone aren't always big and traumatic; sometimes, they're tiny cracks in the bone called stress fractures.

Stress fractures are usually caused by overuse of the bone, (like when you stand around all day on concrete floors, or do a lot of running or jumping), although conditions such as osteoporosis (gradual bone loss) can make even everyday activities (like slow dancing in the kitchen with your broomstick) hazardous for your bones. Certain types of shoes can also increase your risk for developing stress fractures in your feet. High heels put a great deal of strain on the bones that make up the ball of your foot, and it shouldn't be a surprise that wearing concrete blocks on your feet isn't a fantastic idea (especially if you plan to go swimming in a dank and dirty river while wearing them). Those who are overweight also put more strain on their foot bones than those who are not.

Normally, old bone material is resorbed at about the same rate that new bone material is added, which means your bones are usually pretty stable. But, add pressure and stress, and the bone growth can't keep up with the damaged material. Your bones become fatigued, then develop tiny cracks that can lead to stress fractures. And, if stress fractures aren't taken care of, they can lead to more dramatic breaks of the bone.

Because we tend to think of fractures as traumatic events, you may not even be aware that you've developed a stress fracture. When your bones start cracking under the pressure, you're likely to experience pain in the area of the fracture (especially if you press down on the affected bone). This pain may improve with rest at first, and then come back with activity, although it'll likely show up earlier and earlier with each successive workout, and feel worse and worse over time. Eventually, the pain may continue during periods of rest as well. In addition to pain, you may experience swelling, redness, and sometimes even bruising near the stress fracture.

If you experience the symptoms above, it's a good idea to see your podiatrist, who has most definitely seen bones crack under pressure. He or she is, fortunately, also well-versed on treating these damaged bones. In order to ascertain if you've experienced a stress fracture, your podiatrist will take a history of your symptoms and any factors that may be contributing to them. He or she may ask about your shoes, your work environment, the types of sports you're involved with, whether you've recently changed your exercise regimen, the medications you take, any medical conditions you may have, and whether you've stuck your foot in one of those pressure machines lately.

If your podiatrist suspects your bone may be cracking, you might expect him or her to take an X-ray right off. And your podiatrist may do that, although stress fractures don't often show up on X-rays until a few weeks after symptoms appear (although this does NOT mean you should wait a few weeks before seeing your podiatrist). Instead, your doctor may need to order other imaging studies such as an MRI or bone scan. And, of course, there will probably be a physical exam of your foot.

Stress fractures are often treated with rest and sometimes immobilization. You'll need to take a break from many high-impact activities while you heal, although (with doctor approval) you might be able to participate in activities such as swimming, biking or aerobics while your foot heals. However, your podiatrist could recommend staying off the foot entirely, in which case you'll be the lucky recipient of a pair of crutches (and possibly a cast to keep your foot immobile). Your foot may also be protected from stress by stiff-soled shoes or a brace, or you might have a cast boot or fiberglass cast applied to keep your bones in place while they heal.

Applying ice (20 minutes on over a thin towel, 40 minutes off) and keeping your foot elevated above the level of your heart will help keep the swelling and pain at bay. Anti-inflammatory medications such as ibuprofen may also help with the pain, although they can inhibit bone repair. So, your doctor may suggest using acetaminophen instead.

Healing from stress fractures usually takes around six to eight weeks, although it can take twelve weeks or longer. But, no matter how much you're raring to get back to jumping jacks or marathons, it's essential that you give your bones time to heal, or you risk complications like breaking your bone completely. You'll also want to resume your previous activities slowly, so your newly healed bone doesn't collapse again under the pressure.