Suchergebnisse

This study aimed to assess the stability of the performance, pace and turn parameters of elite long-distance male swimmers during an 800 m freestyle race. The sample was composed by 38 male swimmers, participating in the 800 m event at the 2016 LEN European Aquatic Championships (long course meter). The performance, and a set of pace and turn parameters were analyzed. A customized software was used to perform each race analysis. Swimmers spent 64.05 ± 0.50% and 35.95 ± 0.49% of the final race time in the clean swim and turns, respectively. In the pace parameters, the clean swim was the only one that did not differ between the first and second half of the race (1.63 ± 0.05 vs 1.62 ± 0.05 m·s−1), and in the turn parameters, the water break distance was also similar (5.13 ± 1.17 vs 5.06 ± 0.98 m). A significant and moderate-strong variation was verified for the performance (total race lap effect: p < 0.001, η2 = 0.62), and a significant and moderate variation for the pace parameters (total race: p < 0.001, 0.15 ≤ η2 ≤ 0.33), and for the turn parameters (total race: p < 0.01, 0.15 ≤ η2 ≤ 0.33). Present data (pace and turn variation) shows that elite long-distance male swimmers do not maintain a similar pattern during an 800 m freestyle race. Future research is need to understand if this lack of pace and turn stability is the best way to enhance the performance, or if swimmers should be advised to control their pace and turn. Nevertheless, coaches are advised to help swimmers with feedback about their pace (i.e., controlling the intermediate 30 m) and turn performances (i.e., controlling the 5 m in and 15 m out), leading to a positive effect in their final race time. ; To LEN (Ligue Européenne de Natation) and Spiideo AB for providing the videos. This project was supported by the National Funds through FCT – Portuguese Foundation for Science and Technology ( UID/DTP/04045/2013 ) – and the European Fund for regional development ( FEDER ) allocated by European Union through the COMPETE 2020 Programme (POCI-01-0145-FEDER-006969). We would like also to thank the support of the University of Beira Interior and Santander Universities (Bolsa BIPD/ICIFCSH-Santander Universidades-UBI/2017). ; info:eu-repo/semantics/publishedVersion

The aims of this study were to classify, identify and follow-up young swimmers' performance and its biomechanical determinants during two competitive seasons (in seven different moments of assessment-M), and analyze the individual variations of each swimmer. Method: Thirty young swimmers (14 boys: 12.70 +/- 0.63 years-old; 16 girls: 11.72 +/- 0.71 years-old) were recruited. A set of anthropometric, kinematic, efficiency, hydrodynamic and mechanical power variables were assessed. Results: The cluster solution (i.e., number of ideal clusters for this sample) resulted in three clusters, which were named as: cluster 1 ("talented"), cluster 2 ("proficient"), and cluster 3 ("non-proficient"). The performance improved between moments of assessment in all clusters (cluster 1-M1: 68.07 +/- 6.62s vs M7: 61.46 +/- 3.43s; cluster 2-M1: 73.14 +/- 4.87s vs M7: 65.33 +/- 2.97s; cluster 3-M1: 82.60 +/- 4.18s vs M7: 70.09 +/- 3.48s). Anthropometric features also increased between moments of assessment, and remaining biomechanical variables (kinematic, efficiency, hydrodynamic and mechanical power) also increased between M1 and M7, in all clusters. Cluster 1 increased their swimmer's membership between M1 and M7 (4 to 11), cluster 2 decreased (12 to 5), and cluster 3 maintained (14). Conclusion: It can be concluded that the cluster formation depends on different determinant factors during two competitive seasons, and young swimmers are prone to change from one cluster to another over this period of time ; This project was supported by the National Funds through FCT - Portuguese Foundation for Science and Technology [UID/DTP/04045/2019], and the European Fund for regional development (FEDER) allocated by European Union through the COMPETE 2020 Programme [POCI-01-0145-FEDER-006969]. ; info:eu-repo/semantics/publishedVersion

At front crawl, the upper-limbs are responsible fornearly 90% of the forward propulsion ; This project was supported by the National Funds through FCT - Portuguese Foundation for Science and Technology (UID/DTP/0445/2013) and the European Fund for regional development (FEDER? allocated by European Union through the COMPETE 2020 Programme (POCI-01-0145-FEDER-006969) ; info:eu-repo/semantics/publishedVersion

Biomechanics plays an important role helping Paralympic sprinters to excel, having the aerodynamic drag a significant impact on the athlete's performance. The aim of this study was to assess the aerodynamics in different key-moments of the stroke cycle by Computational Fluid Dynamics. A world-ranked wheelchair sprinter was scanned on the racing wheelchair wearing his competition gear and helmet. The sprinter was scanned in three different positions: (i) catch (hands in the 12h position on the hand-rim); (ii) the release (hands in the 18h position on the hand-rim) and; (iii) recovery phase (hands do not touch the hand-rim and are hyperextended backwards). The simulations were performed at 2.0, 3.5, 5.0 and 6.5 m/s. The mean viscous and pressure drag components, total drag force and effective area were retrieved after running the numerical simulations. The viscous drag ranged from 3.35 N to 2.94 N, pressure drag from 0.38 N to 5.51 N, total drag force from 0.72 N to 8.45 N and effective area from 0.24 to 0.41 m2. The results pointed out that the sprinter was submitted to less drag in the recovery phase, and higher drag in the catch. These findings suggest the importance of keeping an adequate body alignment to avoid an increase in the drag force. ; This project was supported by the National Funds through FCT - Portuguese Foundation for Science and Technology (UID/DTP/ 04045/2013) - and the European Fund for regional development (FEDER) allocated by European Union through the COMPETE 2020 Programme (POCI- 01-0145-FEDER-006969). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. ; info:eu-repo/semantics/publishedVersion

The aim was to compare the mechanical power and energy cost of an elite wheelchair sprinter in the key-moments of the stroke cycle. The wheelchair-athlete system was 3D scanned and then computational fluid dynamics was used to estimate the drag force. Mechanical power and energy cost were derived from a set of formulae. The effective area in the catch, release and recovery phases were 0.41m(2), 0.33m(2) and 0.24m(2), respectively. Drag increased with speed and varied across the key-moments. The catch required the highest total power (range: 62.76-423.46W), followed-up by the release (61.50-407.85W) and the recovery (60.09-363.89W). ; This project was supported by the National Funds [FCT - Portuguese Foundation for Science and Technology (UID/ DTP/04045/2013)] and the European Fund for regional development (FEDER) allocated by European Union through the COMPETE 2020 Programme ; info:eu-repo/semantics/publishedVersion

Objectives: This study aimed to (i) assess an anthropometric and thrust inter-limb asymmetry, and; (ii) determine the contribution of anthropometrics, and dry-land upper-body strength and power to the thrust of talented adolescent swimmers. Methods: Eighteen talented adolescent swimmers (12 boys and 6 girls: 15.81 ± 1.62 years old) were evaluated. A set of anthropometric, dry-land upper-body strength and power, and in-water thrust were assessed. Results: Despite the fact that the dominant side presented higher values in anthropometrics (except for the hand surface area) and thrust, non-significant inter-limb differences were found. The symmetry index indicated a symmetry between upper-limbs. Hierarchical linear modeling retained as main predictors of each upper-limb thrust the respective hand surface area (dominant upper limb: estimate = 0.293, 95CI: 0.117; 0.469, p = 0.005; non-dominant upper limb: estimate = 0.295, 95CI: 0.063; 0.526, p = 0.025). The full stroke cycle retained the upper-body dry-land strength as main predictor (estimate = 0.397, 95CI: 0.189; 0.605, p = 0.002). Conclusion: The hand surface area and upper-body strength were the main predictors of each upper-limb and full stroke cycle thrust, respectively. Hence, coaches and practitioners should aim to carefully maximize the hand surface area (by finger spreading) while performing the stroke, as well as dry-land upper-body strength in order to enhance the performance ; This project was supported by the National Funds through FCT-Portuguese Foundation for Science and Technology (UID/DTP/04045/2019), and the European Fund for regional development (FEDER) allocated by the European Union through the COMPETE 2020 Programme (POCI-01-0145-FEDER-006969). We would like also to thank the support of the University of Beira Interior and Santander Universities (Bolsa BIPD/ICIFCSH-Santander Universidades-UBI/2017). ; info:eu-repo/semantics/publishedVersion

The aim of this study was to analyse the detraining process that occurs during a season break, and its influence on the performance, anthropometrics, and biomechanics of young swimmers. The sample included 54 young swimmers (22 boys: 12.79 +/- 0.71 years; 32 girls: 11.78 +/- 0.85 years). Performance for the 100 m freestyle and anthropometric and biomechanical variables were evaluated as main determinants. Performance impaired significantly for boys (2.17%) and girls (1.91%). All anthropometric variables increased between moments of assessment for boys and girls. Overall, the boys enhanced all biomechanical variables during the detraining period, and girls showed mixed results. For both sexes, the stroke index was the variable with the highest increase (boys: Delta = 16.16%; d = 0.89; p = 0.001; girls: Delta = 19.51%; d = 1.06; p = 0.002). Hierarchical linear modelling showed that the height retained the amount of impairment in the performance. One unit of increase in the height (cm) led to less 0.41 s impairment in the performance. Present data indicated that during an 11-weeks detraining period, young swimmers impaired their performance, but the determinant factors showed an impaired relationship. This increase in the determinant factors is mainly related to the increase in the swimmers' anthropometrics. Moreover, the increase in height was responsible for retaining the performance impairment. ; This project was supported by National Funds through FCT -Portuguese Foundation for Science and Technology (UID/DTP/04045/2019), and the European Fund for regional development (FEDER) allocated by the European Union through the COMPETE 2020 Programme (POCI01-0145-FEDER-006969). ; info:eu-repo/semantics/publishedVersion

The main resistive forces (RF) in wheelchair racing are rolling resistance (RR) and aerodynamic drag (D). ; This project was supported by the National Funds through FCT - Portuguese Foundation for Science and Technology (UID/DTP/0445/2013) and the European Fund for regional development (FEDER? allocated by European Union through the COMPETE 2020 Programme (POCI-01-0145-FEDER-006969) ; info:eu-repo/semantics/publishedVersion