Your Body Almanac

Running

Thousands of footstrikes a week, mostly through your shins, knees and feet.

Running is one of the best things you can do for your heart, but every stride lands two to three times your body weight on one leg. Most running injuries are overuse injuries that build quietly when mileage climbs faster than bones and tendons can adapt.

01

Runner's knee

A dull ache around or behind the kneecap is the most common running complaint. It is linked to ramping up mileage, weak hips and thighs, and tight muscles that change how the kneecap tracks. Downhills and stairs usually make it worse.

SourcesPatellofemoral pain syndrome (OrthoInfo, AAOS)
Build up training graduallyWeeklyRaise how often, how long and how hard you train by no more than about 10% a week. Do glute bridgesDailyLift your hips off the floor to strengthen the buttock muscles that sitting tends to switch off. Stretch your quadsDailyA standing stretch for the front of your thighs. Use a foam rollerAs neededSlowly roll sore or stiff muscles for a few minutes after activity or long days.
02

Shin splints and stress fractures

Pain along the inner shin often shows up after a jump in distance or a switch to harder surfaces. If you keep pushing, repeated stress can crack the bone itself. A stress fracture tends to hurt at one specific spot and gets worse with every run.

SourcesShin splints (OrthoInfo, AAOS)Stress fractures (OrthoInfo, AAOS)
Build up training graduallyWeeklyRaise how often, how long and how hard you train by no more than about 10% a week. Wear supportive shoesAs neededChoose shoes that fit well and suit your activity, and replace them when they wear out. Do calf raisesWeeklyRise onto your toes to strengthen calves and ankles for standing, walking and running. Eat calcium-rich foodsDailyGet two or three calcium sources a day to support your bones, from dairy or from fortified and plant foods.
03

Achilles and heel pain

Your Achilles tendon and the plantar fascia under your foot absorb force with every push-off. Tight calves, sudden hill work and worn-out shoes can leave them stiff and sore, often worst with the first steps in the morning.

SourcesAchilles tendinitis (OrthoInfo, AAOS)Plantar fasciitis and bone spurs (OrthoInfo, AAOS)
Stretch your calvesDailyA wall calf stretch for legs that stand, walk or run all day. Do calf raisesWeeklyRise onto your toes to strengthen calves and ankles for standing, walking and running. Wear supportive shoesAs neededChoose shoes that fit well and suit your activity, and replace them when they wear out.
04

Heat illness and dehydration

Running in hot or humid weather raises your core temperature fast. Heavy sweating drains fluid and salt, and heat exhaustion can slide into heat stroke, which is an emergency.

SourcesHeat-related illnesses (CDC)Heat cramps, exhaustion and stroke (National Weather Service)
Stay safe in the heatAs neededOn hot days, drink water often, take breaks in the shade and plan hard work for the cooler parts of the day. Rehydrate when you sweatAs neededDrink regularly during hot work or long workouts, and add electrolytes when you sweat for more than two hours. Drink water through the dayDailyKeep a water bottle within reach and sip through the day instead of waiting until you are thirsty.
05

Sun exposure on long outdoor runs

Hours outdoors add up to a lot of UV over a season, and sweat washes sunscreen off. Runners who train midday get a large share of their lifetime sun exposure this way.

SourcesSun safety facts (CDC)
Wear sunscreen every dayDailyPut broad-spectrum SPF 30+ on exposed skin each morning and reapply every two hours outdoors. Wear sun-protective clothingAs neededCover up with a wide-brimmed hat, UV-blocking sunglasses and tightly woven long sleeves when you are out in the sun. Check your skin for changesAs neededLook over your whole body on a regular schedule for new spots or moles that change, itch or bleed.

When to see a professional

See a doctor or physical therapist for pain at one spot on a bone, pain that makes you limp, swelling that doesn't settle in a few days, or a sudden pop at the back of the ankle. Stop and get emergency help for confusion, fainting, or hot skin, whether dry or still sweating, during a hot run.