Does body composition relate to active drag during arms-only front crawl swimming in male collegiate swimmers?

Fat tissue does not directly contribute to an increase in propulsive force in swimming, though it has the potential to indirectly enhance swimming performance by reducing active drag as the specific gravity of fat tissue is lower than that of water. However, the relationship between body composition and active drag has not been elucidated. This study aimed to evaluate how body composition relates to active drag during arms-only front crawl swimming.

Cross-sectional study.

Twenty-two male collegiate swimmers (height, 1.73 ± 0.06 m; body mass, 67.6 ± 6.0 kg) performed arms-only front crawl swimming using a measuring active drag-system. Active drag was evaluated at 1.20, 1.50 m/s, and maximum swimming velocity. Body composition data, fat mass, fat-free mass, and the percentage of fat mass relative to body mass (%fat mass) were measured using dual-energy X-ray absorptiometry. The associations between body composition data and active drag were evaluated using Pearson's correlation coefficients.

The results indicated that %fat mass was negatively correlated with active drag at 1.20 and 1.50 m/s, whereas fat-free mass was positively correlated with active drag at 1.50 m/s.

In male swimmers with %fat mass between 6.3 and 12.0 %, a higher %FM, reflecting lower body density, had lower active drag at submaximal swimming velocities. These findings suggest that swimmers and their coaches should consider the balance of fat mass and fat-free mass from the perspective of active drag rather than unnecessarily decreasing fat mass or increasing fat-free mass to enhance swimming performance.