Estudo preditibo da intensidade de corrida na meia-maratona com base na relação lactato-velocidade obtida num teste de terreno

Abstract

The purpose of this study was to investigate the validity of a field test in predicting the half-marathon (21095m) performance. Eighteen long-distance runners performed a total of 33 half-marathons and an equal amount of incrementai field tests (4x2000m) to established the relationship between running speed and blood lactate leveis. The speeds used in the field test ranged from 4.2 to 5.8m/s with increments of 0.4m/s in each step. Following each loading levei blood samples were taken from the ear lobe and analysed using an YSI-1500L Sport. Statistical analysis included the Pearson correlation coefficient and the simple linear regression model. The levei of significance was set at 5%. The average time achieved by the runners in the half-marathon was 1h05'41"±3'07". The test speeds corresponding to a lactate concentration between 3.0 and 5.5mmol/l showed an high correlation (0.86<r<0.90) with the half-marathon speed. However the higher correlation (r = 0.90) was found at lactate leveis of 4.5, 5.0 and 5.5mmol/l (V4.5, V5.0 and V5.5). In fact, these values seem to be able to assure the higher predictions since the r2 found was of 80% for V4.5 and 81% for V5 0-V5.5, with the same standard error of estimate (0.1 1). Nevertheless and in spite of the high correlation found, in practical terms our results showed a limited predictive efficacy and practical applicability. In fact, predictions based on V3.0(5.47m/s) to V5.5 (5.78m/s) include a margin of error of ±3'16" for the top athletes, although estimates based on V4.5-V5.5. presented a lower error (± 1 '23"). Additionally 70% of the studied athletes presented a final competition time outside the interval of the prediction based on the 4.5-V5.5.