Grey Zone: A Gap Between Heavy and Severe Exercise Domain

Abstract

The aim of this study was to determine a critical threshold (CT) interpreted as "the highest exercise intensity where V Ȯ2 can be stabilized before reaching 95% of V Ȯ2 max (V Ȯ2 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 Ȯ2 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 Ȯ2 peak. The results showed that work rate corresponding to CT (329.5 6 41.5 W) was significantly greater than that of the MLSS (269.5 6 38.5 W; p 5 0.000), VT (279.6 6 33 W; p 5 0.000), and CP (306.3 6 39.4 W; p 5 0.000), and CP overestimated both VT and MLSS (p 5 0.000). There was no significant V Ȯ2 difference between the 10th and 30th minute of MLSS and MLSS + 15 W exercise (0.36-0.13 ml•min 21 •kg 21 ; p 5 0.621). Exercising V Ȯ2 response of MLSS + 15 W could not exceed the level of 95% V Ȯ2 max (57.02 6 3.87 ml•min 21 •kg 21 and 87.2 6 3.1% of V Ȯ2 max; p 5 0.000), whereas V Ȯ2 responses greater than 95% of V Ȯ2 max were always attained during exercises performed at CT + 15 W (64.52 6 4.37 ml•min 21 •kg 21 and 98.6 6 1% of V Ȯ2 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.

Agreement Between Maximal Lactate Steady State and Critical Power in Different Sports: A Systematic Review and Bayesian’s Meta-Regression

“…These studies have shown that, on average, the peak V Ȯ2 during these trials is not different on average from V Ȯ2 max (16,22,35,65,100,103,131,137). By contrast, recent studies have taken a different approach by determining MV Ȯ2 SS through multiple constant cycling workloads, with 10-15-watt increments (71,107) Even when considering the issue of "V Ȯ2 max attainment," there is strong evidence indicating that the traditional MLSS protocol (which involves trials of 30 minutes with a 1 mmol•L 21 increase in the last 20 minutes) does not accurately represent the MV Ȯ2 SS (5,71,103,107). However, exercising at workloads "slightly" above MLSS (ranging from 12.5 to 8.1%) consistently Figure 6.…”

“…Some authors also argue that the severe-intensity domain is defined by the V Ȯ2 max attainment before or at the point of exhaustion, and the boundary between the heavy and severe intensity domains is established by the highest intensity without V Ȯ2 max achievement (i.e., maximal V Ȯ2 steady state [MV Ȯ2 SS]) (65,75,77,115,116,136). However, it has been shown that MLSS's most traditional protocol does not represent MV Ȯ2 SS (4,5,69,71,90,103,107,111). Conversely, CP has been criticized for several reasons, including the fact that hyperbolic models and their linear derivatives do not accurately reflect the true behavior of power-or speed-time relationship (42,59,60).…”

Evaluation of the Success of Determining the Maximal Lactate Steady-State of a Method Used to Determine the Upper Limit of Severe Exercise Domain: Experimental Research

“…tarafından hesaplanmıştır. 15 Bu yöntemle belirlenen üst sınır, aerobik dayanıklılık geliş-tirmede kullanılabilecek en yüksek oranı, yani aerobik limit gücü (ya da hızı) verir (ALG). Burada ALG, bir ⩒O 2pik yanıtı elde edilebilecek en yüksek egzersiz şiddetidir ve ALG'de sürdürülen bir egzersiz "doğrulanmış" ⩒O 2maks 'ın ⩒O 2 cinsinden ~%96 dolaylarında gerçekleştirilir.…”

“…Burada ALG, bir ⩒O 2pik yanıtı elde edilebilecek en yüksek egzersiz şiddetidir ve ALG'de sürdürülen bir egzersiz "doğrulanmış" ⩒O 2maks 'ın ⩒O 2 cinsinden ~%96 dolaylarında gerçekleştirilir. 15,16 Çok az sayıda çalışma, I HIGH 'da uygulanan bir antrenman modelinin egzersiz etkilerine odaklanmıştır. [17][18][19] Bu çalışmalardan en ilginç olanı, Turnes ve ark.…”

Modelling human endurance: Power laws vs critical power

“…However, as pointed out by Leo et al (2022a), most studies in support of CP thresh only considered exercise intensities that were not in close proximity to the presumed threshold value. More recent studies have found evidence that physiological responses vary much more smoothly and have suggested replacing the threshold notion by a "grey zone" (Ozkaya et al, 2022), a "phase transition" (Pethick et al, 2020) or a "spectrum" (Leo et al, 2022a). The fact that the power-law model does not easily identify thresholds between exercise domains should therefore not be viewed as a drawback of the model but may actually make it more realistic.…”