Relationship between swimming speed, intra-cycle variation of horizontal speed, and Froude efficiency during consecutive stroke cycles in adolescent swimmers
The purpose of this study was to investigate the relationship between swimming
speed, intra-cycle variation of horizontal speed of displacement (dv), and Froude
efficiency (ηF) in front-crawl during three consecutive stroke cycles. The sample
consisted of 15 boys aged 16.07 ± 0.77 years and 15 girls aged 15.05 ± 1.07 years.
Swimming speed, dv and ηF were measured during a 25 m front-crawl trial. Three
consecutive stroke cycles were measured. Swimming speed showed a non-significant
stroke-by-stroke effect (F = 2.55, p = 0.087, η2 = 0.08), but a significant sex effect
(F = 90.46, p < 0.001, η2 = 0.76). The dv and ηF had the same trend as the swimming
speed for the stroke-by-stroke effect, but a non-significant sex effect (p > 0.05).
The Spearman correlation matrix between swimming speed and dv, and swimming
speed and ηF showed non-significant correlations for the three stroke cycles in both
sexes. However, the tendency of the former was not always inverse, and the latter was
not always direct. Coaches and swimmers need to be aware that lower dvs are not
always associated with faster swimming speeds and vice-versa, and that ηF is a
predictor of swimming speed, not dv.
This work is supported by national funds (FCT—Portuguese Foundation for Science and Technology) under the project UIDB/DTP/04045/2020. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
