Ulnar nerve conduction velocity in injured baseball pitchers.

OBJECTIVE: To compare the ulnar nerve conduction velocity (NCV) of baseball pitchers without elbow injury to baseball pitchers with elbow injury and to persons who do not play baseball.

DESIGN: Cross-sectional.

SETTING: Hospital rehabilitation department.

PARTICIPANTS: Eight college baseball pitchers without elbow injury, 8 age-matched controls who did not play baseball, and 8 college baseball pitchers with a history of elbow injury with tenderness over the cubital tunnel area.

INTERVENTION: Supramaximal electric stimulation was applied superficially to the ulnar nerve at the wrist, below the elbow, and above the elbow of both the dominant and nondominant arms of all subjects. M waves were recorded from the abductor digiti minimi muscles.

MAIN OUTCOME MEASURES: The ulnar NCV was calculated separately for the across-elbow and below-elbow segments. The ulnar NCVs of both arms of the 3 groups were compared by using a 2-way (arm by group) analysis of variance, with a statistical significance level of P less than .05.

RESULTS: The ulnar NCVs were 64.40+/-7.34m/s, 54.97+/-8.67m/s, and 59.18+/-4.10m/s for the pitchers without injury, pitchers with injury, and the subjects who were not pitchers, respectively. The pitchers without injury were significantly faster than the other 2 groups. For pitchers without injury, the ulnar NCVs of the dominant arm were significantly faster than those of the nondominant arm (56.26+/-2.63m/s). No significant difference was found between the dominant and nondominant arms for the group of injured pitchers and for the group of subjects who were not pitchers.

CONCLUSIONS: The ulnar NCVs of the injured pitchers did not appear to be abnormal, but were suboptimal in comparison with the noninjured pitchers. The above-normal NCVs observed in the noninjured pitchers may be the result of an adaptation to trauma associated with ball throwing.