Novos meios de avaliar a durabilidade na corrida: a duração crítica e a DC30

Abstract

Durability has emerged as an important component of long-distance running performance, representing the ability to resist physiological degradation over time. It lacks, however, a specific and easily obtainable unit of measurement. Purpose: This study aimed to propose critical duration (CD) as a specific and applicable measure of durability in running, assess its predictive validity through a submaximal heart rate–based model (CD30), and investigate its relationship with training variables. Methods: Thirteen trained runners (5 marathoners and 8 non-marathoners) completed a maximal incremental treadmill test, two-time trials (1200 m and 2400 m) for critical speed (CS) calculation, and a continuous run at 90% of CS to determine CD. Heart rate data from this test were used to develop the CD30 model, based on linear regressions from minutes 10 to 30, estimating the time to reach 94% of HRmax. CD30 estimates were validated using Pearson correlation, Bland–Altman analysis, intraclass correlation coefficient (ICC), and leave-one-out cross-validation (LOOCV). Results: CD was significantly higher in marathoners (77.7 ± 21.0 min) than in non-marathoners (50.0 ± 11.3 min; p < 0.05). CD showed positive correlations with total weekly training volume (r = 0.57), zone 2 volume (r = 0.63), and age (r = 0.69), but was not correlated with CS or maximal aerobic speed. CD30 showed a strong correlation with CD (r = 0.83), good agreement (ICC = 0.83), and low bias (0.58 ± 22.3 min). LOOCV yielded consistent estimates for CD and CD30 (59.6 ± 16.6 min vs. 60.6 ± 19.6 min vs. 60.1 ± 17.2 min). Conclusions: CD is a sensitive indicator of individual differences in durability and reflects training characteristics. CD30 proved to be a valid, submaximal, and practical alternative to estimate CD, with potential application in monitoring runner performance.