10 Most Common Marathon Injuries

Running or walking a marathon of 26.2 miles is a grueling endurance challenge. Marathoners need to prepare properly to prevent common injuries. When a minor injury or symptoms of a problem occur during the marathon, learn how to deal with it and whether it is safe to continue to the finish.



Blisters after Chicago Marathon
Blisters after Chicago Marathon. Credit: Scott Richert ©

Almost everyone will end the marathon with foot blisters. If you have put in your full training schedule, you will have been toughening your feet and building calluses. You will also have experimented with which combination of shoes, socks, drying agents, covering pads, and lubricants work best for you. Blisters endanger your race when they occur in the early miles of the marathon and upset your usual gait for a longer period of time. This impressive array of blisters on all five toes of the right foot is from Scott Richert, who developed them on the Chicago Marathon.

What to do on the go: Stop at the first sign of a hot spot and cover the area with a gel bandage or moleskin pad. If a blister has already developed, you may want to sterilize the area, drain it, and then cover with the bandage or pad.


Black Toenails

Black Toenail
Black Toenail. Credit: Anayah © Deposit Photos

A black toenail is caused by a blister or blood pooling under the nail. During the marathon, this is most often caused by the repeated trauma of your foot sliding forward in your shoe with each step. Prevent black toenails by lacing your shoes to retain your heel in the heel cup and keep your foot from sliding forward in the shoe. Often, you only notice the black toenail after the marathon, rather than it hurting during the marathon. You will lose the toenail and it will grow back over the course of three to five months.

What to do on the go: Nothing. You probably will not feel any discomfort during the marathon.



Full frame of Petroleum jelly
Petroleum jelly can help with chafing. Douglas Sacha / Getty Images

Chafing occurs where skin rubs against skin. Add salt from sweat and you have raw, painful areas. The chief areas that chafe are the underarms, nipples, under-breast area, groin, and thighs. As you discover on your long training days which areas chafe, take measures to keep those areas dry with cornstarch, or lubricate them with petroleum jelly or roll-on silicone products. People who don't wear bras should cover their nipples with adhesive bandages to prevent nipple chafing.

What to do on the go: If your marathon is in a different climate than you trained in, you may chafe in new areas. Most marathons provide petroleum jelly at water stops. Take advantage of it to generously lubricate the areas that are chafing.​


Runners Trots and Nausea

Aidon / Getty Images

Stomach and bowel upsets are very common during the marathon. Use extreme care in what you eat and drink the 48 hours before the marathon. No spicy foods or alcohol. Do not eat anything unfamiliar. Limit your caffeine before the marathon to the minimum you simply must have. Do not overeat as the sheer volume of food still in your digestive system can be the problem. Avoid dairy products if you are lactose-intolerant. If you are prone to runners trots, try Imodium on your training days first to see if it helps. Know the locations of the porta-johns on the route.

What to do on the go: Only use energy snacks and sports drinks that you used on your training walks and runs without ill effects.



Marathon runners rounding corner with paper cups on street
Hero Images / Getty Images

It is important to know how your body handles its needs for fluids by keeping track of it on your long training walk or run. Weigh yourself before and after a long session. You should neither have lost or gained weight. Marathon fluid guidelines state that you should let thirst be your guide unless your experience from weighing on training days shows it is not accurate for you. Signs of dehydration include dry mouth, fatigue, dizziness, stomach ache, back pain, headache, irritability, and decreased urination.

What to do on the go: Slow down or stop. Drink a sports drink until you have recovered. It is unwise to continue the marathon once you have these symptoms.



Gatorade G2 in Sport Bottles
Credit: Ethan Miller / Getty Images Sport

Hyponatremia occurs when you drink too much fluid and your body doesn't have time to eliminate it. This dilutes the salt concentration in your cells, which is very dangerous. Signs of hyponatremia include nausea, headache, cramps, confusion, slurred speech, bloating, and swollen hands.

Hyponatremia has killed runners during the marathon. A study at the Boston Marathon showed that hyponatremia is more common in marathon walkers and slow runners, who spend more time on the course drinking more fluids, regardless of whether they drank only water, only sports drink, or a combination. Don't drink when you aren't yet thirsty, unless your experience shows your sense of thirst isn't accurate.

What to do on the go: Stop and seek medical help. Do not continue with these symptoms.


Sunburn and Windburn

Tokyo Marathon
ICHIRO / Getty Images

Wear a hat with a bill to protect your face and the top of your head. Apply sunscreen to every bit of exposed skin, especially your ears. Protect your lips with a sun-protecting lip balm. Marathoners will spend three to nine hours outdoors, at the mercy of the sun and wind. For cooler, windy days I like to have a Buff neck gaiter to wear as a balaclava or scarf for extra wind protection.

What to do on the go: Slower runners and walkers should reapply sunscreen at the halfway mark. Don't be afraid to beg some from the course volunteers. If you forgot lip balm, use petroleum jelly at the water stops.


Muscle Cramps

Cramp in calf
Jeannot Olivet / Getty Images

Classic leg cramps can hit you during the marathon, especially if you experience dehydration and salt depletion.

What to do on the go: Stop and gently stretch and massage the cramped muscle. Drink sports drink to replace fluids and salt. You can continue once the cramp has eased.

You may also experience strange cramps or muscle spasms in muscles anywhere in your body. This can happen from the strain of using the same posture and gait for several hours. To prevent these, work on proper posture throughout your training walks and runs. During the marathon, think of your posture and relaxing your shoulders. Change up your stride and pace on uphills and downhills. Have fun waving at the crowds or dancing past any on-course bands.


Hitting the Wall

Tired mature female marathon runner resting with hands on knees below sunny urban highrise building
Hero Images / Getty Images

Hitting the wall—completely running out of energy stores in your muscles—is more common in competitive marathon runners than in slower runners or marathon walkers. Walkers have more time to absorb energy calories from sports drinks and energy snacks. To prevent hitting the wall, drink full-strength sugared sports drink throughout the event. Supplement that with energy gels or other energy snacks to replace the number of calories you are expending, approximately 80-100 calories per mile.

What to do on the go: If you feel fatigue on the course, have a snack immediately. If you simply can't go on, stop, snack, drink, and reassess your condition in 10 to 15 minutes.


Sprains, Strains and Stress Fractures

Sports injury
FatCamera / Getty Images

In the crush of runners and walkers, or after long hours on the course, you may sprain an ankle, pull a muscle, or experience a stress fracture. Sharp, sudden, extreme pain that isn't a muscle cramp signals you to stop.

What to do on the go: Don't attempt to keep going. Signal for assistance from the course volunteers.

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Article Sources

  • Christopher S.D., et.al. "Hyponatremia among Runners in the Boston Marathon." N Engl J Med 2005; 352:1550-1556. April 14, 2005​
  • Fredericson M, Misra AK "Epidemiology and aetiology of marathon running injuries." Sports Med. 2007;37(4-5):437-9.