Blood lactate response and ventilatory parameters around the maximal lactate steady state in swimming: A case study

The understanding of the mechanisms that occur at the exercise intensity correspondent to the maximal balance between lactate production and removal, and the intensities above (metabolic imbalance) and below (prolonged metabolic stability), is important to understand the respiratory adjustments that occur in parallel with the lactate responses during aerobic capacity training exercise. The objective of this study was to analyze in a case study, the respiratory adjustments required to perform the maximal lactate steady state test (100%MLSS), and compare them with what happens at intensities above (102.5%MLSS) and below (97.5%MLSS)that gold standard intensity for the evaluation of aerobic capacity. Methods: One elite female endurance swimmer (16 yr; 56 kg; 1.64 m) performed in different days: 1) a intermittent incremental protocol until voluntary exhaustion, with steps of 200m, increments of 0.05m/s and 30s rest intervals to determine the velocity (v), blood lactate concentration ([La-]), expiratory ventilation (VE) and the peak oxygen uptake (VO2peak); 2) three to five 30 min sub-maximal continuous tests to determine v, [La-], VE and oxygen uptake (VO2) corresponding the 100%MLSS, 97.5%MLSS and 102.5%MLSS (Pelarigo et al., 2011). The VO2 and VE values were directly and continuously measured using a telemetric portable gas analyser (K4 b2, Cosmed, Italy), connected to a special respiratory snorkel (Baldari et al., 2011). The values were analyzed at the 3rd and the last minute of the continuous test. Results: At the intensities corresponding the 97.5%MLSS and 100%MLSS (1.30 and 1.33 m/s), a stability in [La-] was observed (1.4 - 1.3 and 1.7 - 1.9 mmol/l, respectively) and a slightly decrease in VO2 and VE from the 3rd to the last minute of exercise (respectively: 50.81/49.7 - 72.68/69.91 and 56.70/51.66 ml.kg/min - 76.71/71.5 l/min). At an intensity of 102.5%MLSS (1.36 m/s), any stability of physiological parameters was not observed - exhaustion at the 27th min ([La-] = 3.3 - 4.1mmol/l) with a slightly decrease in VO2 and increase in VE between the 3rd and the last minute of exercise (57.90/57.30 ml.kg/min and 82.94/97.12 l/min). At the intensity corresponding the VO2peak (1.44 m/s), the values of VO2, VE and [La-] were, respectively, 72.59 ml.kg.min-1, 90.74 l/min and 4.4 mmol/l. Conclusions: Thus, even the exercise being conducted or in stability or in metabolic imbalance, it seems that the swimmer adopts other adjustments (hydrodynamic drag / propulsive efficiency) to decrease the oxygen uptake between the 3rd and the last minute of exercise during the 30min test, making the aerobic bioenergetic system apparently more efficient along time.
© Copyright 2012 17th Annual Congress of the European College of Sport Science (ECSS), Bruges, 4. -7. July 2012. Julkaistu Tekijä Vrije Universiteit Brussel. Kaikki oikeudet pidätetään.

Aiheet: uinti laktaatti ventilaatiokynnys urheilufysiologia hapenottokyky maksimi
Aihealueet: kestävyys urheilu biologiset ja lääketieteelliset tieteet
Julkaisussa: 17th Annual Congress of the European College of Sport Science (ECSS), Bruges, 4. -7. July 2012
Toimittajat: R. Meeusen, J. Duchateau, B. Roelands, M. Klass, B. De Geus, S. Baudry, E. Tsolakidis
Julkaistu: Brügge Vrije Universiteit Brussel 2012
Sivuja: 301-302
Julkaisutyypit: kongressin muistiinpanot
Kieli: englanti (kieli)
Taso: kehittynyt