July 1, 2005 -- From Little League to the Big League, any baseball player can tell you that catching a fastball can hurt, and now a new study shows it.
Researchers found that despite improvements made to the catcher's mitts used by professional baseball players, the gloves still do not adequately protect the hand from repetitive injury.
"We found signs of early blood vessel damage that could lead to significant symptoms and could end a player's career," says researcher T. Adam Ginn, MD, chief resident in orthopaedics at Wake Forest University Baptist Medical Center in Winston-Salem, N.C., in a news release. "The glove's current design does not protect the hand from trauma."
Catchers may receive 150 pitches per game at speeds sometimes over 90 miles per hour, plus warm-up and practice pitches that could add up to 300 catches per day.
Researchers say catcher's mitts are designed to ensure that most pitches are caught at the base of the webbing (at the bottom of the index finger, where many blood vessels and nerves are located). But fielder's mitts are designed to catch the ball in the webbing itself, away from the hand.
That means catchers may face higher risks of blood vessel injury due to the repetitive impact of the ball hitting the gloved hand. Over time, this can lead to reduced blood flow and damaged nerves with symptoms including numbness and tingling, reduced sensitivity to cold, and blue-tinged skin.
Catcher's Mitts Fail Protection Test
In the study, researchers examined 36 players on four minor league baseball teams in North Carolina in 2001. The players included nine catchers, seven infielders, and 15 pitchers.
Researchers asked the players about symptoms of injury in the hand and used ultrasound and other testing to evaluate blood circulation in the hands. They also looked for other signs of injury, such as enlarged fingers.
The results showed that catchers had abnormal blood flow in the gloved hand compared with the other hand. In addition, catchers had index fingers that were an average of nearly two ring sizes bigger on the gloved vs. the nongloved hand -- a sign of injury.
Researchers found catchers were more likely than other players to have hand weakness, with 44% of catchers reporting this symptom compared with 7% of infielders and 17% of outfielders.
Catchers also reported more symptoms of weakness, numbness, tingling, and pain in their gloved hands (56%) vs. their throwing hands (11%).
Researchers say that these symptoms occurred during games and not at rest, which leads them to believe they are caused by nerve trauma in the hand rather than reduced blood flow. But they say the early blood vessel damage found in the study could lead to permanent circulation problems.
"Despite well-padded catchers' mitts and the use of additional padding, the catchers examined in this study continue to demonstrate changes to the gloved index finger consistent with trauma," says Ginn. "There should be further study into glove design."
The results appear in the current issue of the Journal of Bone & Joint Surgery.