Analysis of the ability of catcher's masks to attenuate head accelerations on impact with a baseball.

Objective: The goals of this study were to measure the ability of catcher's masks to attenuate head accelerations on impact with a baseball and to compare these head accelerations to established injury thresholds for mild traumatic brain injury.

Design: Testing involved using a pneumatic cannon to shoot baseballs at an instrumented Hybrid III headform (a 50th percentile male head and neck) with and without a catcher's mask on the head. The ball speed was controlled from approximately 26.8 to 35.8 m/s (60-80 mph), and the regulation National Collegiate Athletic Association baseballs were used.

Setting: Research laboratory.

Patients: None.

Independent Variables: Catcher's masks and impact velocity.

Main Outcome Measures: The linear and angular head accelerations of the Hybrid III headform.

Results: Peak linear resultant acceleration was 140 to 180 g without a mask and 16 to 30 g with a mask over the range of ball's speed investigated. Peak angular resultant acceleration was 19 500 to 25 700 rad/s without a mask and 2250 to 3230 rad/s with a mask. The Head Injury Criterion was 93 to 181 without a mask and 3 to 13 with a mask, and the Severity Index was 110 to 210 without a mask and 3 to 15 with a mask.

Conclusions: Catcher's masks reduced head acceleration metrics by approximately 85%. Head acceleration metrics with a catcher's mask were significantly lower than contemporary injury thresholds, yet reports in the mass media clearly indicate that baseball impacts to the mask still occasionally result in mild traumatic brain injuries. Further research is needed to address this apparent contradiction.