ABSTRACT
The aim of the study was to investigate the existence of a difference in the force appllied by a rower to a scull when two kinds of rowing blades are used (Macon blade, symnmetric and big blades, asymmetric) at the same stroke rate (number of rows per minute). The hypotheses of this study were that (1) there is a difference in the force applied by a rower to a boat when different kinds of rowing blades are used, and (2) the big blade will provide an increase in the force applied to move the bot compared to the Macon blade. A scull was tied to the four sides of a 25 m swimming pool by six steel cables: one on the bow, one on the stern, and four laterally in order to obtain the resultant force applied by the rower to the boat. Five rowers from three different rowing teams from Porto Alegre (Brazil) gave written consent to be the subjects of this study. All subjects rowed for five minutes with each blade, maintaining a stroke rate of approximately l0 strokes per minute. Root mean square (RMS) values were calculated for each force curve obtained. A t-test was used Lo compare the differences betwecn the RMS force values obtained (big blade B Macon blade) and a one-way ANOVA was used to verify if the group was heterogeneous. The level of significance adopted was 0.05. A 13.13 por cento difference was observed, indicating a higher efficiency of the big blade when compared to the Macon blade. The results presented in this study show that all athletes, using both blade types, were able to exert more force with the asymmeletric blade (big blade) than with the symmetric blade (Macon). These results suggest that the asymmetric blade provides a better performance at the same stroke rate during competition