AUTHOR=Andersson Erik P. , Björklund Glenn , McGawley Kerry 

TITLE=Anaerobic Capacity in Running: The Effect of Computational Method

JOURNAL=Frontiers in Physiology

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2021.708172

DOI=10.3389/fphys.2021.708172

ISSN=1664-042X

ABSTRACT=To date, no study has compared anaerobic capacity estimates computed with the maximal accumulated oxygen deficit (MAOD) method and the gross energy cost (GEC) method applied to treadmill running exercise. Purpose: Four different models for estimating anaerobic energy supply during treadmill running exercise were compared. Methods: Fifteen endurance-trained recreational athletes performed, after a 10-min warm-up, five 4-min stages at ~55–80% of peak oxygen uptake, and a 4-min time trial (TT). Two linear speed-metabolic rate regression models were used to estimate the instantaneous required metabolic rate during the TT (MR_TT_req), either including (5+Y_LIN) or excluding (5-Y_LIN) a measured Y-intercept. Also, the average GEC (GEC_AVG) based on all five submaximal stages, or the GEC based on the last submaximal stage (GEC_LAST), were used as models to estimate the instantaneous MR_TT_req. The anaerobic capacity was computed as the difference between the MR_TT_req and the aerobic metabolic rate integrated over time. Results: The GEC remained constant at ~4.39 ± 0.29 J∙kg-1∙m-1 across the five submaximal stages and the TT was performed at a speed of 4.7 ± 0.4 m∙s-1. Compared with the 5-Y_LIN, GEC_AVG, and GEC_LAST models, the 5+Y_LIN model generated a MR_TT_req that was ~3.9% lower, with corresponding anaerobic capacities from the four models of 0.72 ± 0.20, 0.74 ± 0.16, 0.74 ± 0.15, and 0.54 ± 0.14 kJ∙kg-1, respectively (F1.07,42=13.9, P=0.002). The GEC values associated with the TT were 4.22 ± 0.27 and 4.37 ± 0.30 J∙kg-1∙m-1 for 5+Y_LIN and 5-Y_LIN, respectively (calculated from the regression equation), and 4.39 ± 0.28 and 4.38 ± 0.27 J∙kg-1∙m-1 for GEC_AVG and GEC_LAST, respectively (F1.08,42=14.6, P<0.001). The absolute typical errors in anaerobic capacity ranged between 0.03-0.16 kJ∙kg-1 for the six pair-wise comparisons and the overall standard error of measurement was 0.16 kJ∙kg-1. Conclusions: These findings demonstrate a generally high disagreement in estimated anaerobic capacities between models and show that the inclusion of a measured Y-intercept in the linear regression (i.e., 5+Y_LIN) is likely to underestimate the MR_TT_req and the GEC associated with the TT, and hence the anaerobic capacity during maximal 4-min treadmill running.