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- Characterization of speed fluctuation and drag force in young swimmers: A gender comparisonPublication . Barbosa, Tiago M.; Costa, Mário Jorge; Morais, Jorge; Morouço, Pedro; Moreira, Marc; Garrido, Nuno; Marinho, Daniel; Silva, AntónioThe aim of this study was to compare the speed fluctuation and the drag force in young swimmers between genders. Twenty-three young pubertal swimmers (12 boys and 11 girls) volunteered as subjects. Speed fluctuation was measured using a kinematical mechanical method (i.e., speedo-meter) during a maximal 25-m front crawl bout. Active drag, active drag coefficient and power needed to overcome drag were measured with the velocity perturbation method for another two maximal 25m front crawl bouts with and without the perturbation device. Passive drag and the passive drag coefficient were estimated using the gliding decay velocity method after a maximal push-off from the wall while being fully immersed. The technique drag index was also assessed as a ratio between active and passive drag. Boys presented meaningfully higher speed fluctuation, active drag, power needed to overcome drag and technique drag index than the girls. There were no significant gender differences for active drag coefficient, passive drag and passive drag coefficient. There were positive and moderate-strong associations between active drag and speed fluctuation when controlling the effects of swim velocity. So, increasing speed fluctuation leads to higher drag force values and those are even higher for boys than for girls.
- Effects of Dry-Land Strength and Conditioning Programs in Age Group SwimmersPublication . Amaro, Nuno; Marinho, Daniel; Marques, MC; Batalha, Nuno; Morouço, PedroAmaro, NM, Marinho, DA, Marques, MC, Batalha, N, and Morouço, PG. Effects of dry-land strength and conditioning programs in age group swimmers. J Strength Cond Res 31(9): 2447-2454, 2017-Even though dry-land S&C training is a common practice in the context of swimming, there are countless uncertainties over its effects in performance of age group swimmers. The objective was to investigate the effects of dry-land S&C programs in swimming performance of age group swimmers. A total of 21 male competitive swimmers (12.7 ± 0.7 years) were randomly assigned to the Control group (n = 7) and experimental groups GR1 and GR2 (n = 7 for each group). Control group performed a 10-week training period of swim training alone, GR1 followed a 6-week dry-land S&C program based on sets and repetitions plus a 4-week swim training program alone and GR2 followed a 6-week dry-land S&C program focused on explosiveness, plus a 4-week program of swim training alone. Results for the dry-land tests showed a time effect between week 0 and week 6 for vertical jump (p < 0.01) in both experimental groups, and for the GR2 ball throwing (p < 0.01), with moderate to strong effect sizes. The time × group analyses showed that for performance in 50 m, differences were significant, with the GR2 presenting higher improvements than their counterparts (F = 4.156; p = 0.007; (Equation is included in full-text article.)= 0.316) at week 10. Concluding, the results suggest that 6 weeks of a complementary dry-land S&C training may lead to improvements in dry-land strength. Furthermore, a 4-week adaptation period was mandatory to achieve beneficial transfer for aquatic performance. Additional benefits may occur if coaches plan the dry-land S&C training focusing on explosiveness.
- The Interaction Between Intra-Cyclic Variation of the Velocity and Mean Swimming Velocity in Young Competitive SwimmersPublication . Barbosa, Tiago M.; Morouço, Pedro; Jesus, S.; Feitosa, W. G.; Costa, Mário Jorge; Marinho, Daniel; Silva, António; Garrido, NunoThe aim of this study was to assess the relationship between the intra-cyclic variation of the horizontal velocity (dv) and the velocity of the 4 competitive swimming techniques in young swimmers. 45 young swimmers performed a set of maximal 4 × 25 m (freestyle, backstroke, breaststroke and butterfly stroke) swims with in water start. A speed-meter cable was attached to the swimmer's hip. The dv and the swimming velocity were analyzed. Within-subject tests presented significant variations in the dv based on the swimming technique. Post-hoc test revealed significant differences across all pair-wised swimming techniques (P<0.001), except for the comparison between freestyle and backstroke (P=0.98). The dv was higher in the breaststroke, followed by the butterfly, the backstroke and the freestyle. The quadratic models had the best goodness-of-fit and the lower error of estimation for the relationship between the dv and the swimming velocity in all swimming techniques (0.24 ≤ R(2) ≤ 0.51). As a conclusion, there is a non-linear relationship where the increase of swimming velocity leads to a decrease of dv in young competitive swimmers.