Relationship Between Critical Speed and Long-Distance Swimming Performance: An Exploratory Study

This exploratory study aimed to evaluate the association of single- and multi-parameter models based on short-distance front crawl dash (i.e., 400 [T₄₀₀] and 50 [T₅₀] meters [m]) and critical speed (CS) with long-distance performance in talented swimmers. T₄₀₀ and T₅₀ of 26 women and 22 men (15.6±1.6 y) were tested in a controlled setting and used to compute critical speed. Associations between long-distance swimming performance of 800 and 1,500 m events and critical speed, T₄₀₀, or T₅₀ were examined, using single- (separate simple linear regressions) and multi- (multiple linear regressions with a cluster-robust standard error) parameter models. Multi-parameter models' predictors (age, sex, D', and rate of perceived exertion after 50 and 400 m) were selected using the backward-elimination procedure. Critical speed and T₄₀₀ showed the greatest explanatory capacity in single-parameter models in both 800 (critical speed: adjusted R ²=0.802; T₄₀₀: adjusted R ²=0.796; T₅₀: adjusted R ²=0.383) and 1,500 m performance (critical speed: adjusted R ²=0.807; T₄₀₀: adjusted R ²=0.805; T₅₀: adjusted R ²=0.454). Multi-parameter models showed a similar model fit for both 800 (critical speed: adjusted R ²=0.807; T₄₀₀: adjusted R ²=0.801; T₅₀: adjusted R ²=0.802) and 1,500 m (critical speed: adjusted R ²=0.808; T₄₀₀: adjusted R ²=0.804; T₅₀: adjusted R ²=0.805) performance. Multi-parameter models offered little improvement over single-parameter models (800 m: Δadjusted R ²=0.005; 1,500 m: Δadjusted R ²=0.001), suggesting that critical speed or T₄₀₀ alone may provide a practical and non-invasive tool for estimating long-distance swimming performance in talented athletes.