Background: The supraspinatus muscle plays an important role in initiating shoulder abduction and maintaining glenohumeral joint stability. Identifying the shoulder position that produces maximal supraspinatus activation is important for effective rehabilitation and strengthening programs. Objective: To evaluate the optimal shoulder position for maximal activation of the supraspinatus muscle using electromyography. Materials and Methods: This prospective observational study was conducted in Jhansi from January 2025 to December 2025. A total of 100 participants aged 18–60 years were included. Surface electromyography was used to record supraspinatus muscle activity in different shoulder positions, including neutral position (0°), 30°, 60°, and 90° abduction, scaption with internal rotation, and scaption with external rotation. Each movement was performed three times, and the mean EMG values were recorded and analysed. Results: The results showed significant variation in supraspinatus activation across different shoulder positions. The highest mean EMG activity was observed during scaption with external rotation, followed by scaption with internal rotation and 60° shoulder abduction. The lowest activation was recorded in the neutral position. Statistical analysis showed a significant difference between the tested positions (p < 0.05). Conclusion: Scaption with external rotation produced the greatest supraspinatus muscle activation and may be considered the optimal position for strengthening the supraspinatus in rehabilitation programs.