This study aimed to clarify the effects of parachute swimming on upper limb muscle activity and its immediate impact on muscle activity during free swimming without resistance. Eight competitive swimmers performed 15-m sprint front-crawl swims in the following order: (1) free swimming, (2) parachute swimming, and (3) free swimming after parachute swimming. The final 10-m time, video footage, and surface EMG data from six muscles were analysed. The 10-m time increased during parachute swimming, but no improvement was confirmed in the subsequent free swimming. During parachute swimming, the pull phase was extended and the recovery phase shortened. EMG analysis showed no increase in muscle activity during parachute swimming compared to free swimming. However, changes in the activation onset of the triceps brachii and middle deltoid were observed across the trials, and a reduction in flexor carpi ulnaris activity during the recovery phase was found immediately after parachute swimming.
