# Comparison of the Hydrodynamic Profile Between Competitive Triathletes and Swimmers

## TL;DR

Triathletes have worse hydrodynamic performance than swimmers, which affects their swimming speed and suggests a need for targeted training.

## Contribution

The study identifies specific hydrodynamic differences and correlations with performance between triathletes and swimmers.

## Key findings

- Triathletes showed higher passive drag and lower force/power to overcome drag compared to swimmers.
- Triathletes' 200 m and 25 m times correlated with passive drag and power, while swimmers' 25 m time correlated with in-water force.
- Swimmers demonstrated hydrodynamic superiority, leading to higher swimming velocity due to better force application.

## Abstract

Objectives: This study aimed to compare the hydrodynamic profile between triathletes and competitive swimmers and to establish associations with short- and middle-distance performance. Methods: A total of 18 male athletes, including 10 swimmers and 8 triathletes, all registered in their respective federations, underwent assessments of passive drag, active drag and power, tethered swimming force, kinematics, and performance over a 200 m and 25 m front crawl. Group comparisons were performed using either Student’s t-test or the Mann–Whitney U test at a significance level of p ≤ 0.05. Results: The triathletes presented higher passive drag and lower levels of force and power to overcome drag. Correlation analysis showed that, among the triathletes, both times at 200 m and 25 m were associated with mean passive drag (r = 0.68 to 0.86) and power (r = −0.58 to −0.80), whereas in swimmers, the mean in-water force was the single variable associated with time at 25 m (r = −0.51). Conclusions: There is a clear hydrodynamic superiority of swimmers compared to triathletes, reflecting their higher mean swimming velocity due to a greater ability to apply force. This suggests that specific technical interventions for triathletes, focusing on drag reduction and improvements in propulsive power, are needed to close this gap with swimmers.