DETERMINATION OF CRITICAL POWER IN SWIMMING

Abstract

1248 The critical velocity (CV) has been accepted as a good estimator of the anaerobic threshold in swimming. However, originally, the critical power concept assumes hyperbolic relation between power output, not velocity, and time to exhaustion. The present study was designed in order to: a) establish the actual critical power (CP) in swimming using the work-time CP model (W-T); b) compare the prediction of the swimming performance between the W-T and classical distance-time CV model (D-T). The power output (Po) was determined according to the Bernolli law, Po=Cx.d.S.v3 which relates the drag coefficient (Cx), water density (d), body surface area (S), and swimming velocity (v). The Cx was assumed to be constant at any swimming velocity and was determined using hydrodynamic body drag method proposed by Kolmogorov and Duplischeva (1992). Swimmers were submitted to the 50m, 100m and 200m all-out trials and their anaerobic threshold (AT, 4mM fixed blood lactate concentration velocity) were also determined. The CP and the anaerobic work capacity (AWC) were determined by the work-time linear model, using the 100 m and 200 m power output. The power output during the 50, 100 e 200 m all-out trial were respectively, 1.76 ± 0.81, 1.25 ± 0.53 e 0.96 ± 0.33 w/kg. The power output at AT (0.72 ± 0.18 w/kg) and the CP (0.61 ± 0.16 w/kg) were similar and highly correlated (r=0.94). The AWC (22.0 ± 12.0 J/kg) accounted for a greater portion of variance in shorter all-out trials, and CP in the longer ones. The residuals of W-T model in the prediction of all-out trials were lower than the D-T model. It was concluded that: a) the critical power can be calculated in swimming; b) the swimming performance in short distance event can be more accurate predicted using power output than velocity. Finnacial Support: CNPq 522153/96-8