Purpose The purpose of this study was to investigate the immediate effects of supernumerary robotic limb (SRL) training on embodiment, forearm muscle activity, and functional performance in healthy adults. Methods Five healthy adults participated in this study. Participants performed SRL training using a data glove and a robotic hand system (uHand 2.0). Before and after training, a random sequence typing task was performed. Surface electromyography was used to measure muscle activity of the flexor digitorum and extensor digitorum muscles. Functional performance was evaluated using total keystrokes, typing accuracy, and characters per minute (CPM). Subjective embodiment was assessed using an embodiment questionnaire. Pre and post training differences were analyzed using the Wilcoxon signedrank test. Results Following SRL training, electromyography values of both the flexor digitorum and extensor digitorum significantly decreased(p<.05). Total keystrokes, typing accuracy, and characters per minute significantly increased after training. Significant improvements were observed in embodiment questionnaire items Q1, Q3, Q4, and Q5(p<.05). Conclusion SRL training improved motor efficiency and functional performance while promoting embodiment of the robotic limb. These findings suggest that SRL systems may have potential applications in human augmentation and rehabilitation settings.