Shin

Two bones in your lower leg

Your shin bone (tibia) is the bigger bone in your lower leg, and it carries most of your weight. Next to it is a thinner bone called the fibula.

Bones get stronger with training

Every time you run and jump, your bones break down a tiny bit. With rest and sleep, they build back up, and can even get stronger.

But if you add too much too fast, your bones can break down faster than they can rebuild.

Myth or fact?

• Your bones can get stronger from training. Fact. Bones can come back stronger after exercise, as long as you build up slowly and get enough rest and sleep.

Shin splints

Shin splints are pain along the inside edge of your shin. They usually show up when you suddenly run a lot more or a lot harder, run on hard surfaces, or wear worn-out shoes.

Stress fractures

A stress fracture is a tiny crack in a bone from too much repeated pounding. It usually hurts in one small spot. At first it hurts only after activity, but it can start to hurt during activity and even when walking.

Myth or fact?

• A stress fracture always comes from one big fall or hit. Myth. Stress fractures build up over time from lots of repeated impact, not one big hit.

Add a little at a time

When you start a new season or training plan, add running slowly instead of jumping way up all at once. Bone stress injuries often show up 3 to 4 weeks after a new routine starts.

Shoes, surfaces, and shin guards

Replace running shoes when they're worn out. Mix in softer surfaces like a track or a trail. In soccer, always wear shin guards to protect your lower legs.

Myth or fact?

• Eating enough food, including calcium and vitamin D, helps keep your bones strong. Fact. Bones need fuel to rebuild. Not eating enough for how much you train raises the risk of a bone stress injury. Vitamin D is important for bone health too.

Back off and switch it up

If your shins hurt, take a break from running and jumping. With an adult's OK, you can keep fit with low-impact activities like swimming or biking.

Myth or fact?

• The best fix for shin splints is to run through the pain until it goes away. Myth. Shin splints get better with rest, not more running. Exercising through bone pain can lead to a stress fracture, so rest first, then come back slowly.