Range of motion limited in professional baseball pitchers

Now that the Chicago White Sox have swept the Houston Astros in the World Series, most baseball players are taking some time to rest. Time off is especially important for pitchers because throwing a baseball overhand is both an unnatural motion and a burden on the shoulder and the elbow. Now a research team led by Washington University sports medicine specialists has found that professional pitchers have significantly decreased range of motion in their throwing elbows.

The researchers report in the American Journal of Sports Medicine on a study of 33 professional baseball pitchers. Trainers and team doctors measured the pitchers’ ability to bend, straighten and rotate their elbows and found that range of motion in the dominant elbow was limited when compared to the other arm.

Pitchers often lose range of motion in their pitching elbows.
Pitchers often lose range of motion in their pitching elbows.

“On average, pitchers had an 8 degree loss of the ability to straighten their elbow when compared to the elbow in their non-dominant arm,” says first author Rick W. Wright, M.D., assistant professor of orthopaedic surgery and co-director of the Division of Sports Medicine at Washington University School of Medicine and Barnes-Jewish Hospital in St. Louis. “But despite the fact that they lose range of motion, we’ve been unable to show that there’s a functional impact.”

The pitchers in the study not only couldn’t straighten their arm as far, called extension, they also had difficulty bending the elbow (flexion). A pitcher’s dominant elbow bent about 5 degrees less than the elbow in his other arm. But the study found no significant difference in the ability of the elbow to rotate, (supination and pronation).

Wright, the head team physician for the St. Louis Cardinals, says it’s unclear how the losses in range of motion occur.

“Once we looked at all of the data and did the statistical analysis, we could not find a correlation between increased age, innings pitched or injuries,” he says. “We could not find anything that explained why range of motion was inhibited in the pitching elbow.”

That was a surprise.

Rick Wright
Rick Wright

Although it’s not clear why the losses in range of motion occur, Wright says it is clear that the loss is not enough to hurt a pitcher’s ability to perform on the mound. He says even with the losses in motion, most pitchers are still flexible enough to throw a baseball effectively. He also says the losses in motion should not have a negative impact on normal daily activities outside of baseball.

It’s likely professional pitchers start with strong, flexible elbows that can take high amounts of stress, qualities that helped get them to the Major Leagues, Wright says.

“By the time they reach this level, a lot of people have been eliminated who didn’t have elbows that could stand up to these stresses,” he says. “These players definitely have shown that their elbows are made for pitching.”

But not right now. With the World Series in the rear-view mirror and Spring Training still months away, he says sensible pitchers are resting their elbows.

“At this time of year, I recommend that pitchers shut it down as far as throwing a baseball,” he says. “They need this time to rest and to work on basic strengthening and stretching. In December or January, they’ll restart a throwing program with the goal of being ready when Spring Training begins.”

Wright RW, Steger-May K, Wasseerlauf BL, O’Neal ME, Weinberg BW, Paletta GA. Elbow Range of Motion in Professional Baseball Pitchers. The American Journal of Sports Medicine, vol. 34(2); Oct. 11, 2005.

Washington University School of Medicine’s full-time and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children’s hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked third in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children’s hospitals, the School of Medicine is linked to BJC HealthCare.