Grey Zone: A Gap Between Heavy and Severe Exercise Domain

Ozkaya, O, Balci, GA, As, H, Cabuk, R, and Norouzi, M. Grey zone: A gap between heavy and severe exercise domain. J Strength Cond Res 36(1): 113-120, 2022-The aim of this study was to determine a critical threshold (CT) interpreted as the highest exercise intensity where V?o(2) can be stabilized before reaching 95% of V?o(2)max (V?o(2)peak) and compare it with commonly used anaerobic threshold indices. Ten well-trained male cyclists volunteered for this study. Ventilatory threshold (VT) was determined from incremental tests. Multisession constant-load trials were performed to reveal V?o(2)max. Mathematically modeled critical power (CP) was estimated through the best individual fit parameter method. Maximal lactate steady state (MLSS) was detected by 30-minute constant-load exercises. The individual CT load of each cyclist was tested by constant-load exercises to exhaustion with +15 W intervals until minimal power output to elicit V?o(2)peak. The results showed that work rate corresponding to CT (329.5 +/- 41.5 W) was significantly greater than that of the MLSS (269.5 +/- 38.5 W; p = 0.000), VT (279.6 +/- 33 W; p = 0.000), and CP (306.3 +/- 39.4 W; p = 0.000), and CP overestimated both VT and MLSS (p = 0.000). There was no significant V?o(2) difference between the 10th and 30th minute of MLSS and MLSS + 15 W exercise (0.36-0.13 ml center dot min(-1)center dot kg(-1); p = 0.621). Exercising V?o(2) response of MLSS + 15 W could not exceed the level of 95% V?o(2)max (57.02 +/- 3.87 ml center dot min(-1)center dot kg(-1) and 87.2 +/- 3.1% of V?o(2)max; p = 0.000), whereas V?o(2) responses greater than 95% of V?o(2)max were always attained during exercises performed at CT + 15 W (64.52 +/- 4.37 ml center dot min(-1)center dot kg(-1) and 98.6 +/- 1% of V?o(2)max; p > 0.05). In conclusion, this study indicates that there is a grey zone between heavy and severe exercise domain. This information may play a key role in enhancing athletic performance by improving the quality of training programs.