Pitching Can Work for You - and Against You

[July, 2007] Repeated pitching affects movement in a young man's arm, according to research that shows that regularly throwing a baseball hampers one kind of motion, while boosting another.

These findings were presented earlier this week at the 2007 annual meeting of the American Orthopaedic Society for Sports Medicine, in Calgary, Alberta, Canada.

The changes in throwing arm flexibility are "not necessarily a bad thing and may actually allow better velocity and less injury," says study principal investigator Scott D. Mair, Ph.D., associate professor of orthopedic surgery at the University of Kentucky in Lexington.

However, when pitchers overdo it, he says, pain can result.

At issue is the ability of the arm, and the shoulder in particular, to withstand repeatedly throwing a baseball. Young men in particular may be prone to injury, because some play the game year-round, and because the bones and muscles in their arms are still growing and changing.

Pitching May Protect from Injury

In the new study, conducted in 2006, physicians examined the arms of 32 male baseball pitchers, averaging 18 years of age, six years after an initial examination. Radiologists also took X-rays of the pitchers' shoulders.

Dr. Mair's team found that the pitchers actually gained what is called "external rotation" - "with your arm straight out to the side, you can rotate it back further like you were cocking to pitch," Dr. Mair says. That is a good thing, and it might even protect the shoulder from injury.

However, the young players also lost range of motion in what is called "internal rotation" (moving the arm in the opposite direction, as in letting a pitch go).

The latter "is a permanent change that you can find in virtually anyone who threw a lot as a kid," Dr. Mair says. "It does not seem to result in any permanent significant effects on life outside of throwing."

It was also normal for the pitchers to lose some external rotation in the non-throwing arm over time as they grew.

Flexibility Improves with Stretching

According to Dr. Mair, better flexibility is a very good thing for the pitchers to develop and not just to lower their earned-run average: "External rotation is important in throwers and pitchers in generating velocity and may protect (the arm) from injury," he said.

Malachy McHugh, Ph.D., director of research at the Nicholas Institute of Sports Medicine and Athletic Trauma at Lenox Hill Hospital in New York City, says the movements involved in throwing a ball appear to have different effects on flexibility. "The loss of internal rotation is probably related to deceleration after you release the ball. And the increase in external rotation is from repetitively moving your arm," he explains.

Injuries occur when the loss of internal rotation becomes too great, Dr. McHugh says, adding that stretching is one way to help young pitchers cut this loss of internal rotation. According to the American Academy of Orthopaedic Surgeons (AAOS), studies have shown that cold muscles are more prone to injury. Warming up by running or walking in place for three to five minutes, or holding each stretch at least 30 seconds should help.

And, of course, pitchers should avoid playing too much. While there are no specific guidelines for number of innings pitched per week, the general recommendation is around four to ten innings per week, says the AAOS.

What is next? According to Dr. Mair, there is "still a lot of work to be done in finding out how the growth plate responds to throwing, how to keep kids from being injured, determining pitch counts and days of rest needed, and in educating kids, parents and coaches."

Always consult your physician for more information.