Tracking the performance, energetics and biomechanics of international versus national level swimmers during a competitive season

Mário J Costa,Jean E Mejias,José A Bragada,Hugo Louro,Daniel A Marinho,António J Silva,Tiago M Barbosa

doi:10.1007/s00421-011-2037-6

Abstract

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 (TP(1), TP(2), TP(3)) 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 × 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 (η (p)@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 TP(1) and TP(3). 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.

Highlights

The identification of the variables that can predict the swimming performance is one of the main topics in swimming science
It was considered that Int level swimmers are the ones (N = 4; 20 ± 3.40 years old; 1.83 ± 0.08 m of height; 73.15 ± 10.13 kg of body mass; 21.76 ± 1.53 kg.m-2 of body mass index; 1.90 ± 0.09 m of arm span and; 112.39 ± 4.22 s of personal record in the 200 m freestyle event) with regular participation on international meetings in the previous season, representing the Portuguese National Swimming Team
Wilcoxon tests demonstrated no significant differences between pair wise time periods

Summary

Introduction

The identification of the variables that can predict the swimming performance is one of the main topics in swimming science. Decreases in blood lactate concentrations related to swimming velocity were observed after 6 months of aerobic training (Wakayoshi et al 1993). A training program based on the stroke frequency–velocity relationship can improve the swimmer’s biomechanical and energetic profile enhancing the swimming performance (Termin and Pendergast 2000). When monitoring changes in test measures for 3.6 ± 2.5 years, the stroke frequency at 4 mmol L-1 of blood lactate concentration (SF@V4) for males (r = 0.41) and the skinfolds for females (r = -0.53), showed to be reliable variables to predict the Breaststroke performance (Anderson et al 2008). It was reported that the stroke index (SI) best correlates to the 400-m freestyle performance for both young male and female swimmers (Latt et al 2009a, b)

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