EO SwimBETTER^® Device in Measuring Kinematic and Kinetic Variables: Validity, Reliability, and Sensitivity

Objectives: The aim of this study was to analyze the utilization of the EO SwimBETTER^® (EoLab, Sydney, Autralia) device for measuring kinetic and kinematic variables during 50 m and 200 m freestyle trials. Methods: Ten swimmers (seven males and three females, 20 ± 3.5 years) participated. Each completed three sets of 50 m using EO SwimBETTER^® on non-consecutive days, with a 200 m test performed during the third session after recovery to complete the Critical Swim Speed Test (CSS-T). All tests were conducted at maximal intensity. Results: The results showed high reliability for both kinetic and kinematic parameters. Regarding validity, the EO SwimBETTER^® demonstrated strong agreement with the reference device in measuring stroke frequency (SF). In addition, higher mean force values were found in the 50 m compared with the 200 m trial (Δ% = 8.75%, p = 0.099), suggesting sensitivity of the device to different exertion demands. Conclusions: Based on these findings, the EO SwimBETTER^® appears to be a useful and promising tool for monitoring technical and performance-related variables in swimming, although further research is needed.