Milivoj Dopsaj & Klara Siljeg

The study aims to determine the relationship between variables that define body composition characteristics and sprint swimming performance in elite male butterfly sprinters. The study was conducted over a seven-year longitudinal period with subjects aged 18 to 24 years. During the mentioned period, the subject was measured 10 times, with body composition measurements by multichannel segmental bioimpedance method with the InBody720 device realized a week before the most important competition, regardless of the length of the pool (25 or 50 m pool) or swimming distance (50 or 100 m). The results of the correlation analysis showed that only skeletal muscle mass index (SMMI) was statistically significantly correlated with swimming performance (r = -0.917 to - 0.971), and that correlation was slightly higher on the 50 m compared to the 100 m distance, as well as the results achieved in the 25 m compared to the 50 m pool. No statistically significant correlation was found for the other body composition variables used in this research (fat mass index - FMI, protein-fat index - PFI, percent of skeletal muscle mass - PSMM, index of body composition - IBC and percent of body fat - PBF). This research has shown that it is necessary to establish a research principle, that the impact of body composition changes and relationships on sports performance should be realized as an individual methodological procedure in elite sports.

KEY WORDS: Body composition; Swimming performance; Butterfly stroke; Individual approach.

DOPSAJ, M. & SILJEG, K. Relationship between body composition and sprint swimming performances in butterfly sprinter: Seven- year longitudinal single-case study. Int. J. Morphol., 43(4):1260-1266, 2025.