Percorrer por autor "Garrido, N."
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- Force production and spatial arm coordination profile in arm crawl swimming in a fixed positionPublication . Karsai, István; Garrido, N.; Louro, Hugo; Leitão, L.; Magyar, F.; Alves, F.; Silva, AntónioThis study analyzed the relationship between mechanical force production and spatial arm position of the swimming movement for each side of the swimmer. Eight internationally recognized male swimmers performed fix positioned arm only swimming with a dynamometer synchronized with underwater cameras. The upper arm positions (α in side, β in frontal view) and the elbow angles (γ in 3D) were determined at the moment where the force production reached the peak (Fmax) and the maximal values of rate of force development (RFDmax). RFDmax and α values showed significant differences between the sides (P<0.05). To show the motion integration structure of the performance, Multiple Regression Analysis (MRA) was employed separately for both sides. For the criterion variable, the impulse of force (ImpF50%) was calculated. The defined parameters as the mechanical and spatial predictor system were used for the model. The results of the MRA showed that the predictor system yielded the model structure of the variables that explain the criterion variables for ImpF50% by the dominant (P=0.007) and by the nondominant side (P=0.001), respectively. The alternate contribution of the variables to the models can objectively express the performance difference between the two sides of the swimmer.
- Tethered swimming in crawl: Arm stroke propulsive force at different 5 swim ratesPublication . Leitão, L.; Karsai, I.; Louro, Hugo; Garrido, N.; Conceição, A.; Conceição, AnaOBJECTIVE: A swimmers performance results from the interaction of propulsive and resistive forces, which can only increase by reducing the resistive forces, or increase the propulsives forces (Toussaint, 2006). Researchers have developed many methods for this type of evaluation, tethered swim (Dopsaj et al., 2003, Taylor et al., 2001) and Mad System (Toussaint, 2006). METHODS: Six males’ swimmers of the portuguese national team (21.8+.9yrs,73.64+6.9 bm,182.26+6.1bh) performed only the arm crawl swimming task, on an ergometer without breathing, with tied and supported legs, and with the head placed in a helmet containing a sensor of force, connected to a computer. The frequency increment was set at 5 cycle/min(C/M) from 35C/M to 55C/M. Four underwater cameras were used to kinematical analysis with APAS. Descriptive statistics were used, and Pearson correlation to identify the correlation between the increase of the propulsive force and swim rate, with a level of significance of p. DISCUSSION & CONCLUSION: The most effective swim rate is the 45C\\M which the swimmer can develop greater propulsive force (128.01 N) whether or not the fastest swim rate analyzed, and the insweep action is the most propulsive on all stroke phases.