The influence of stroke mechanics into energy cost of elite swimmers

Abstract

The purpose of this study was to analyze the relationships between energy cost (C), swimming velocity (v), stroke frequency (SF) and stroke length (SL) in top-level swimmers. Eighteen elite swimmers (four freestylers, five backstrokers, five breaststrokers and four butterflyers) performed an intermittent set of nx200 m swims (n<or=8) with increasing velocity. The oxygen consumption was measured breath-by-breath by a portable metabolic cart (K4 b2, Cosmed, Rome, Italy). A respiratory snorkel and valve system with low hydrodynamic resistance was used to measure pulmonary ventilation and collect expiratory gases. Blood samples were taken from the ear lobe before and after each swim to analyze the blood lactate concentration (YSI 1500L, Yellow Springs, OH, USA). At Backstroke, Breaststroke and Butterfly strokes, increases of SF were associated to increases of C, even when controlling the v. The increases in SL only promoted significant decreases in the C in Breaststroke. There was a significant and polynomial relationship between v and SF for all competitive swimming techniques. The polynomial relationship between v and SL was significant only in Freestyle and Butterfly stroke. Partial correlations between v and SF controlling the effect of SL and between v and SL controlling the effect of SF, were positive and significant for all techniques. It is concluded that manipulation of stroke mechanics variables (SF and SL) may be one of the factors through which C in competitive swimming can be altered for a given v.

Critical Evaluation of Oxygen-Uptake Assessment in Swimming

“…Afterwards, enlarging the field of evaluation, the four competitive swimming techniques were studied by this Portuguese research group, observing the primary outcomes: (i) significant relationships between energy expenditure and intra-cycle variation, C and velocity (Barbosa et al, 2005a); (ii) that front crawl was the most economic technique, followed by backstroke, butterfly, and breaststroke (Barbosa et al, 2006); and (iii) the manipulation of the SR and SL might be one of the factors through which energy cost can be altered for a given velocity (Barbosa et al, 2008). As competitive distances vary in swimming, Seifert et al (2010) studied the effect of swimming speciality (sprinters vs. long distance swimmers) in C (and in motor organization), observing that both groups had an increase in C of swimming with increasing velocity.…”

Applicability of an Indirect VO2max Test: Its Association with the 400 Meters Freestyle Performance

“…A swimming test can be a good tool to evaluate competitive swimmers rather than recreational swimmers or for health purposes 11,[25][26][27] . While verifying the reproducibility of the PSwT, Veronese da Costa, Costa, Carlos, Guerra, Silva, Barbosa 11 regarded the NLP as a predictor of the physical conditioning of the non-expert swimmers due to the fact the distance over a predetermined time was used as a criterion for exercise intensity in swimming 11 .…”

A eficiência propulsiva e a performance em nadadores não experts

“…Teoricamente, foi definida a existência de uma relação directa da ηp com a distância de ciclo (DC) e inversa com a FG (Toussaint, & Hollander, 1994). Mais ainda, sabe-se que existe uma relação inversa entre o C e o ηp (Barbosa, Fernandes, Keskinen, & Vilas-Boas, 2008) e verificou-se a existência de uma relação positiva entre o C e a FG (Barbosa, Keskinen, Fernandes, Colaço, Carmo, & Vilas-Boas, 2005). Por outro lado, sugere-se a existência de uma associação significativa entre a ηp e diversas características antropométricas.…”

“…Não obstante este tipo de estudos ser frequente em nadadores adultos e de elite (p.e., Barbosa et al, 2008;Cappaert et al, 1992aCappaert et al, , 1992bToussaint, 1990), poucos são os trabalhos desta índole nos escalões de formação (p.e., Zamparo, 2006). Mais ainda, tanto quanto é possível apurar não há nenhuma investigação sobre esta temática em jovens nadadores não experts.…”