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- Stability of elite freestyle performance from childhood to adulthoodPublication . Costa, M.J.; Marinho, D.A.; Bragada, José A.; Silva, A.J.; Barbosa, Tiago M.Stability of athletic performance is important for practitioners and coaches, since it allows the selection of appropriate training methods and prediction of ages for best results. We performed a longitudinal study of 1694 season-best performances of 242 elite-standard swimmers throughout their careers, from 12 to 18 years of age. Mean stability (descriptive statistics and oneway repeated-measures ANOVA, followed by a Bonferroni post-hoc test) and normative stability (Cohen’s kappa tracking index and the Pearson correlation coefficient) were determined for seven consecutive seasons. Performance improvements in all events were observed (14.36–18.97%). Bonferroni post-hoc tests verified changes in almost all events assessed. Cohen’s kappa demonstrated low stability (0.17–0.27) in relative performance. Pearson correlations only became high from 15 to 16 years in the 50-m and 100-m events, and from 16 to 17 years in the 200-m, 400-m, and 1500-m events. Our results show that: (a) swimmers should display a substantial improvement (14–19%) to become elite standard as adults, such as at 18 years; (b) 16 is the age at which the ability to predict adult performance increases markedly.
- Tracking the performance, energetics and biomechanics of international versus national level swimmers during a competitive seasonPublication . Costa, M.J.; Bragada, José A.; Mejias, J. Erik; Louro, Hugo; Marinho, D.A.; Silva, A.J.; Barbosa, Tiago M.The purpose of this study was to track and compare the changes of performance, energetic and biomechanical profiles of international (Int) and national (Nat) level swimmers during a season. Ten Portuguese male swimmers (four Int and six Nat level subjects) were evaluated on three different time periods (TP1, TP2, TP3) of the 2009–2010 season. Swimming performance was assessed based on official time’s lists of the 200-m freestyle event. An incremental set of 7 9 200 m swims was applied to assess the energetic and biomechanical data. Measurements were made of: (1) velocity at the 4 mmol of lactate levels (V4), stroke index at V4 (SI@V4) and propelling efficiency at V4 (gp@V4), as energetic estimators; (2) stroke length at V4 (SL@V4) and stroke frequency at V4 (SF@V4), as biomechanical variables. The results demonstrated no significant variations in all variables throughout the season. The inter-group comparison pointed out higher values for Int swimmers, with statistical differences for the 200 m performance in all time periods. Near values of the statistical significance were demonstrated for the SI@V4 in TP1 and TP3. The tracking based on K values was high only for the SI@V4. It is concluded that a high stability can be observed for elite swimmers performance, energetic and biomechanical profiles throughout a single season. Int swimmers are able to maintain a higher energetic and biomechanical capacity than Nat ones at all times. The SI@V4 may be used as an indicator of performance variation.
- Tracking the performance of world-ranked swimmersPublication . Costa, M.J.; Marinho, D.A.; Reis, Victor M.; Silva, A.J.; Marques, Mário C.; Bragada, José A.; Barbosa, Tiago M.Tracking the swimming performance is important to analyze its progression and stability between competitions and help coaches to define realistic goals and to select appropriate training methods. The aim of this study was to track world-ranked male swimmer’s performance during five consecutive seasons (from 2003/2004 to 2007/2008) in Olympic freestyle events. An overall of 477 swimmers and 2385 season best performances were analyzed. FINA’s male top-150 rankings for long course in the 2007-2008 season were consulted in each event to identify the swimmers included. Best performances were collected from ranking tables provided by the National Swimming Federations or, when appropriate, through an internet database (www.swimranking.net). Longitudinal assessment was performed based on two approaches: (i) mean stability (descriptive statistics and ANOVA repeated measures, followed by a Bonferroni post-hoc test) and; (ii) normative stability (Pearson Correlation Coefficient and the Cohen’s Kappa tracking index). Significant variations in the mean swimming performance were observed in all events between all seasons. Performance enhancement was approximately 0.6 to 1 % between seasons leading up to the Olympics and approximately 3 to 4 % for the overall time-frame analyzed. The performance stability based on overall time-frame was moderate for all freestyle events, except in the 50-m (K = 0.39 ± 0.05) where it was low. Selfcorrelations ranged between a moderate (0.30 ≤ r < 0.60) and a high (r ≥ 0.60) stability. There was also a performance enhancement during all five seasons analyzed. When more strict time frames were used, the analysis of swimming performance stability revealed an increase in the third season. So, coaches should have a long term view in what concerns training design and periodization of world-ranked swimmers, setting the third season of the Olympic Cycle as a determinant time frame, due to performance stability until Olympic Games season.