Shoulder

A ball in a shallow socket

The top of your upper arm bone (humerus) is shaped like a ball. It sits in a shallow socket, kind of like a golf ball on a tee.

That's why your shoulder can move in more directions than any other joint. It also makes it easier to hurt.

The rotator cuff holds it in place

The rotator cuff is a group of four muscles and their tendons that wrap around the ball. They help keep it in the socket every time you throw, swing, or swim.

The collarbone connects it all

Your collarbone runs from the middle of your chest out to your shoulder. It connects your arm to the rest of your body, and a fall onto your shoulder can break it.

Overuse: too much of the same motion

Throwing, swimming, and serving in tennis or volleyball all use the same shoulder motion over and over. Without enough rest, all that repeating can cause overuse injuries, like sore and irritated tendons.

Your bones are still growing

Kids have growth plates, softer areas near the ends of bones where new bone grows. Too much throwing can irritate the growth plate at the top of the upper arm. Doctors call it Little League shoulder.

Falls and hits

Falling onto your shoulder or an outstretched arm can break your collarbone. A hard fall or hit can also pop the ball out of the socket. That's called a dislocation.

Myth or fact?

• Pitching when your arm feels tired raises your chance of getting hurt. Fact. Pitch counts exist to keep pitchers from throwing on a tired arm. Slower or less accurate throws can be an early sign your arm is tired, so stop and rest.
• If your arm is sore, throwing more will help it get stronger. Myth. A sore arm needs rest, not more throws. Throwing through pain can turn a small problem into an injury that takes months to heal.

Follow pitch counts and rest days

Youth baseball has pitch count limits for each age, plus required rest days after pitching. They exist to protect growing arms.

Pitch Smart also says to take at least 4 months off from throwing every year.

Warm up your arm slowly

Take at least 10 minutes. Start with jogging and arm circles, then short, easy throws. Then slowly back up to longer, harder throws.

Build the muscles that hold your shoulder

Exercises with light resistance bands make your rotator cuff and the muscles around your shoulder blade stronger. A coach or athletic trainer can show you how.

Myth or fact?

• Pitching for two different teams in the same season is a good way to get better faster. Myth. Kids who play on more than one team in a season are more likely to get overuse injuries. Two teams can mean too many pitches and not enough rest.

Stop and tell an adult

If your shoulder hurts while you throw, or after a fall, stop playing and tell your coach, athletic trainer, or a parent.

Myth or fact?

• If your shoulder pops out, you should push it back in yourself. Myth. Only a doctor or trained medical staff should put a shoulder back in place. Keep the arm still and get medical help right away.
• Once your shoulder stops hurting, you can go right back to full-speed throwing. Myth. You need full motion and normal strength first. Then you build back up slowly with a throwing program so the shoulder can handle it again.