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- Stability and prediction of 100-m breaststroke performance during the careers of elite swimmersPublication . Costa, M.J.; Marinho, D.A.; Reis, Victor M.; Silva, A.J.; Bragada, José A.; Barbosa, Tiago M.The aim of this study was to track and analyze the 100-m Breaststroke performance stability throughout elite swimmer’s career. 35 Portuguese male top-50 were analyzed for seven consecutive seasons between 12 and 18 years old. Best performances were collected from ranking tables. Longitudinal assessment was performed based on two approaches: (i) mean stability was analyzed by descriptive statistics and ANOVA repeated measures for each season followed by a post-hoc test (Bonferroni test), (ii) normative stability was analyzed with self-correlation (Malina, 2001) and the Cohen’s Kappa tracking index (Landis and Koch, 1977). There was a 100-m Breaststroke performance enhancement from children to adult age. The overall career performance prediction was low. The change from 13 to 14 years can be a milestone, where the ability to predict the final swimmer’s performance level strongly increases.
- 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.
- Longitudinal study in male swimmers: a hierachical modeling of energetics and biomechanical contributions for performancePublication . Costa, M.J.; Bragada, José A.; Marinho, D.A.; Lopes, Vitor P.; Silva, A.J.; Barbosa, Tiago M.The aim of this study was to assess the pooled and individual response of male swimmers over two consecutive years of training and identify the energetic and biomechanical factors that most contributed for the final performance. Nine competitive swimmers (20.0 +/- 3.54 years old; 10.1 +/- 3.41 years of training experience; 1.79 +/- 0.07 m of height; 71.34 +/- 8.78 kg of body mass; 22.35 +/- 2.02 kg.m(-2) of body mass index; 1.86 +/- 0.07 m of arm span; 116.22 +/- 4.99 s of personal record in the 200 m long course freestyle event) performed an incremental test in six occasions to obtain the velocity at 4 mmol of blood lactate (V-4) and the peak blood lactate concentrations (La-peak) as energetics, and the stroke frequency (SF), stroke length (SL), stroke index and swim efficiency as biomechanical variables. Performance was determined based on official time's lists of 200 m freestyle event. Slight non-significant improvements in performance were determined throughout the two season period. All energetic and biomechanical factors also presented slight non-significant variations with training. Swimmers demonstrated high inter-individual differences in the annual adaptations. The best performance predictors were the V-4, SF and SL. Each unit of change V4, SF and SL represented an enhancement of 0.11 s, 1.21 s and 0.36 s in performance, respectively. The results show that: (i) competitive male swimmers need at least two consecutive seasons to have slight improvements in performance, energetics and biomechanical profiles; (ii) major improvements in competition performance can be accomplished by improving the V-4, SF and SL based on the individual background.
- Longitudinal study in 3,000 m male runners: relationship between performance and selected physiological parametersPublication . Bragada, José A.; Santos, Paulo; Maia, José A.R.; Colaço, Paulo; Lopes, Vitor P.; Barbosa, Tiago M.The purpose of the present study was to analyze longitudinal changes in 3,000 m running performance and the relationship with selected physiological parameters. Eighteen well-trained male middle-distance runners were measured six times (x3 per year) throughout two consecutive competitive seasons. The following parameters were measured on each occasion: maximal oxygen uptake (VO2max), running economy (RE), velocity at maximal oxygen uptake (vVO2max), velocity at 4mmol L-1 blood lactate concentration (V4), and performance velocity (km·h-1) in 3,000 m time trials. Values ranged from 19.59 to 20.16 km·h-1, running performance; 197 to 207 mL·kg-1·km-1. RE; 17.2 to 17.7 km·h-1, V4; 67.1 to 72.5 mL·kg-1·min-1, VO2max; and 19.8 to 20.2 km·h-1, vVO2max. A hierarchical linear model was used to quantify longitudinal relationships between running performance and selected physiological variables. Running performance decreased significantly over time, between each time point the decrease in running velocity was 0.06 km·h-1. The variables that significantly explained performance changes were V4 and vVO2max. Also, vVO2max and V4 were the measures most strongly correlated with performance and can be used to predict 3,000 m race velocity. The best prediction formula for 3,000 m running performance was: y = 0.646 + 0.626x + 0.416z (R2=0.85); where y = V3,000 m velocity (km·h-1), x = V4 (km·h-1) and z = vVO2max (km·h-1). The high predictive power of vVO2max and V4 suggest that both coaches and athletes should give attention to improving these two physiological variables, in order to improve running performance.