Introduction: The ulnar nerve at the elbow is mechanically vulnerable due to its superficial position, particularly in sports involving repetitive elbow movements. Its anatomical location in the groove near the medial epicondyle of the humerus exposes it to pressure and stretching during each elbow flexion, potentially causing microtrauma and affecting its function. Handball players, due to the explosive upper limb movements like throwing, may be more exposed to mechanical stress. Repetitive and continuous loading can lead to adaptations in the peripheral nervous system, which may be reflected in electrophysiological parameters. Purpose: To determine potential differences in the electrophysiological parameters of the ulnar nerve between female handball players and non-athletes, with a focus on the dominant arm. Methods: The study included 31 healthy women (15 handball players and 16 non-athletes). At the Clinical Institute of Clinical Neurophysiology, we performed nerve conduction studies on both ulnar nerves. We measured the amplitude of the M-wave and sensory nerve action potentials using electrical stimulation at three points: at the wrist, below the elbow, and above the elbow. We also determined motor and sensory conduction velocities in the forearm and across the elbow on both arms. The Shapiro-Wilk test was used to assess the normality of data distribution. Differences between arms were analyzed using paired t-tests, while differences between the two groups were assessed using independent t-tests. Results: No significant differences were found between the groups regarding age or body height. In handball players, significantly higher CMAP amplitudes were measured at the wrist of the dominant arm compared to the non-dominant arm and at all three stimulation sites compared to non-athletes. Handball players also demonstrated significantly higher motor conduction velocity across the elbow on the dominant side compared to the non-dominant. In non-athletes, the average motor conduction velocity was higher below the elbow and lower across the elbow on the non-dominant side. There were no significant group differences in motor conduction velocities or sensory fiber conduction, and no conduction blocks were observed. Discussion and conclusion: Higher amplitudes and motor conduction velocities in handball players suggest functional adaptations of the neuromuscular system resulting from regular training, rather than ulnar nerve impairment.
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