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In 1973 Wasserman, Whipp, Koyal, and Beaver published a groundbreaking study titled "Anaerobic threshold and respiratory gas analysis during exercise". At that time, respiratory gas analysis and laboratory computers had evolved such that more advanced respiratory exercise physiology studies were possible. The initial publications from this group on the onset of anaerobic metabolism in cardiac patients, the first breath-by-breath VO 2 system, the first description of the anaerobic threshold, and then later new methods to detect the anaerobic threshold have been and continue to be highly cited. In fact, their 1973 anaerobic threshold paper is the sixth and their 1986 paper is the second most cited paper ever published in the Journal of Applied Physiology. The anaerobic threshold concept has also generated>5500 publications with the rates increasing over time. The publication of two papers that help to refute the "anaerobic" explanation for this phenomenon had no effect on the rates of citations of the original anaerobic threshold papers or the number of anaerobic threshold papers published since. Thus, despite now substantial evidence refuting the proposed anaerobic mechanisms underlying this phenomenon, these papers continue to be highly influential in the discipline of exercise physiology and, perhaps even more explicitly, clinical exercise physiology., Competing Interests: The author has no conflicts of interest relative to this manuscript. The author asserts that the manuscript is consistent with the IJSM ethical standards 46., (Thieme. All rights reserved.)

Introduction: Obesity is a condition that generally limits work capacity and predisposes to a number of comorbidities and related diseases, the last being COVID-19 and its complications and sequelae. Physical exercise, together with diet, is a milestone in its management and rehabilitation, although there is still a debate on intensity and duration of training. Anaerobic threshold (AT) is a broad term often used either as ventilatory threshold or as lactate threshold, respectively, detected by respiratory ventilation and/or respiratory gases (VCO 2 and VO 2 ), and by blood lactic acid., Aims and Methodology: This review outlines the role of AT and of the different variations of growth hormone and catecholamine, in subjects with obesity vs normal weight individuals below and beyond AT, during a progressive increase in exercise training. We present a re-evaluation of the effects of physical activity on body mass and metabolism of individuals with obesity in light of potential benefits and pitfalls during COVID-19 pandemic. Comparison of a training program at moderate-intensity exercise (< AT) with training performed at moderate intensity (< AT) plus a final bout of high-intensity (> AT) exercise at the end of the aerobic session will be discussed., Results: Based on our data and considerations, a tailored strategy for individuals with obesity concerning the most appropriate intensity of training in the context of rehabilitation is proposed, with special regard to potential benefits of work program above AT., Conclusion: Adding bouts of exercise above AT may improve lactic acid and H + disposal and improve growth hormone. Long-term aerobic exercise may improve leptin reduction. In this way, the propensity of subjects with obesity to encounter a serious prognosis of COVID-19 may be counteracted and the systemic and cardiorespiratory sequelae that may ensue after COVID-19, can be overcome. Individuals with serious comorbidities associated with obesity should avoid excessive exercise intensity., (© 2021. The Author(s).)

Purpose: To estimate the influence of global anaerobic fatigue on rhythm performance., Methods: Fifteen young males participated in the experiment. Anaerobic fatigue was induced with 2 consecutive running-based anaerobic sprint tests (RAST). The level of lactate was controlled before the first RAST and 3 minutes after each RAST. The rhythm performance was assessed by using Optojump Next (Microgate, Bolzano, Italy). The rhythm test was conducted 3 times, before fatigue and immediately after each RAST. Eight variables of the rhythm test were analyzed: the mean frequency of jumps for the assisted and unassisted phase (XfAP and XfUAP), SD of jump frequency for the assisted and unassisted phase (SDfAP and SDfUAP), and mean absolute error for the assisted and unassisted phases of the test (XERAP and XERUAP, respectively)., Results: One-way repeated-measures analysis of variance showed a significant main effect of anaerobic effort on rhythm variables only in the unassisted phase of the test. Statistically significant differences were observed in XfUAP between the first and third rhythm measurements (F2,28 = 4.98, P < .014, ηp2=26.23%), SD of jump frequency for the unassisted phase (SDfUAP; F2,28 = 3.48, P = .05, ηp2=19.9%), and mean absolute error for the unassisted phase (XERUAP; F2,28 = 3.36, P = .006, ηp2=19.43%)., Conclusions: The results show that rhythm of movement may be negatively influenced after intensive anaerobic fatigue. The exact mechanism of this phenomenon is not precisely defined, but both central and peripheral fatigue are suspected to be involved.

Abstract: Byrd, MT, Wallace, BJ, Clasey, JL, and Bergstrom, HC. Contributions of lower-body strength parameters to critical power and anaerobic work capacity. J Strength Cond Res 35(1): 97-101, 2021-This study examined the contribution of lower-body strength and isokinetic peak torque measures to the prediction of critical power (CP) and anaerobic work capacity (AWC). Fourteen recreationally trained males (mean ± SD age: 22.4 ± 2.5 years; height: 177.9 ± 7.7 cm; body mass: 84.2 ± 12.4 kg) with anaerobic training experience participated in this study. The lower-body strength measures included 1 repetition max bilateral back squat (BSq), isokinetic peak torque at 30°·s-1 [PT30], and isokinetic peak torque at 240°·s-1 [PT240] of the dominant leg. The CP and AWC were determined from the 3-minute all-out CP cycle ergometer test (CP3MT), with the resistance set at 4.5% of the total body mass. The CP was defined as the mean power output over the final 30 seconds of the test, and the AWC was calculated using the equation, AWC = 150 seconds (P150 - CP), where P150 equals the mean power output for the first 150 seconds. Stepwise regression analyses indicated that only BSq contributed significantly to the prediction of AWC (AWC = 0.0527 [BSq] + 8.094 [standard error of estimate = 2.151 kJ; p = 0.012]), with a correlation of r2 = 0.423. None of the strength parameters significantly predicted CP. These findings indicated that BSq strength accounted for 42% of the variance in AWC, but lower-body strength was not related to CP. The current results indirectly support the unique metabolic characteristics of both CP and AWC in providing separate measures of an individual's aerobic and anaerobic capabilities, respectively., (Copyright © 2018 National Strength and Conditioning Association.)

Background: The aim of this study was to examine the value preoperative AT as predictor of postoperative survival in patients who underwent elective EVAR for repair of asymptomatic AAA., Methods: Consecutive patients who underwent elective EVAR between 2008 and 2018 were analyzed. Cardiopulmonary exercise testing was performed. Perioperative 30-day mortality was compared between patients who had AT ≥8 mL/kg/min and those with AT<8 mL/kg/min. Risk factors for postoperative survival following EVAR were examined using Cox's regression analysis., Results: Between 1 st January 2008 and 31 st December 2017, 430 patients underwent elective EVAR (standard device: N.=374, fenestrated/branched: N.=56); their median age was 76 years (range: 53-91 years), median AT was 9.3 (range: 5.4-16.1), and 30-day mortality was 0.9%. These patients were followed up for a median of 1630 days. There was no significant difference in perioperative 30-day mortality between patients who had AT≥8 and those who had AT<8 (χ 2 =1.56, P=0.22). Age (HR=1.51 [CI: 1.07-1.99], P<0.05) and AT (HR=0.59 [CI: 0.45-0.76], P=0.0003) were predictors of reduced postoperative survival following elective EVAR whereas gender (HR=0.75 [CI: 0.4-1.4], P=0.37), AAA diameter (HR=0.95 [CI: 0.77-1.16], P=0.6), and AAA morphology (HR=1.23 [CI: 0.68-1.76], P=0.95) were not., Conclusions: Anaerobic threshold is an independent predictor of prolonged survival following elective EVAR and can be used to identify patients who receive most benefit from elective EVAR.

Sixteen female soccer players (age = 20.19 ± 1.52 years; body mass = 56.52 ± 4.95 kg; body height = 164.81 ± 4.21 cm) with no history of lower extremity injury participated in the study. The Biodex SD Balance system was used to determine the non-dominant single-leg stability. In anaerobic exercise, each subject performed four maximal cycling efforts against a resistance equivalent to 0.075 kg/body mass for 30 s with three-minute rest intervals. In aerobic exercise, subjects performed the Bruce protocol on a motorized treadmill. After each exercise, subjects subsequently performed a single-leg stability test and then repeated the same test for four times with five-minute passive rest periods. In accordance with the results, it was found that the impairment observed right after the aerobic loading was higher ( p < 0.001) compared to the anaerobic one. However, the time-related deterioration in both aerobic and anaerobic loadings was similar. The B-pre value was lower than B post and B 5 ( p < 0.01) and B 10 ( p < 0.05) in both conditions. Subjects could reach the initial balance level at B 15 after aerobic and anaerobic loadings. The lactate level did not reach resting value even after 20 min of both fatigue protocols. Although the fatigue after aerobic and aerobic exercise negatively affects a single-leg dynamic balance level, single leg balance ability returns to the baseline status after 10 min of passive recovery duration.

The ability of anaerobic microorganisms to proliferate under extreme conditions is of widespread importance for microbial physiology, remediation, industry, and evolution. The halophilic alkalithermophiles are a novel group of polyextremophiles. Tolerance to alkaline pH, elevated NaCl concentrations, and high temperatures necessitates mechanisms for cytoplasmic pH acidification; permeability control of the cell membrane; and stability of proteins, the cell wall, and other cellular constituents to multiple extreme conditions. Although it is generally assumed that extremophiles growing at more than one extreme combine adaptive mechanisms for each individual extreme, adaptations for individual extremes often counteract each other. However, in alkaline, hypersaline niches heated via intense solar irradiation, culture-independent analyses have revealed the presence of an extensive diversity of aerobic and anaerobic microorganisms belonging to Bacteria and Archaea that survive and grow under multiple harsh conditions. Thus, polyextremophiles must have developed novel adaptive strategies enabling them to grow and proliferate under multiple extreme conditions. The recent isolation of two novel anaerobic, halophilic alkalithermophiles, Natranaerobius thermophilus and Halonatronum saccharophilum, will provide a platform for detailed biochemical, genomic, and proteomic experiments, allowing a greater understanding of the novel adaptive mechanisms undoubtedly employed by polyextremophiles. In this review, we highlight growth characteristics, ecology, and phylogeny of the anaerobic halophilic alkalithermophiles isolated. We also describe the bioenergetic and physiological problems posed by growth at the multiple extreme conditions of alkaline pH, high NaCl concentration, and elevated temperature under anoxic conditions and highlight recent findings and unresolved problems regarding adaptation to multiple extreme conditions.

Purpose: The purpose of this study was to evaluate muscle strength and anaerobic power in young boys with hemophilia compared with healthy boys., Methods: Thirteen boys with severe hemophilia (H) (mean (+/- SD) age = 12.0 +/- 3.17 yr) and 16 control (C) boys (age = 11.9 +/- 2.8 yr) performed elbow and knee flexion and extension on the Biodex System II dynamometer at two angular velocities. They also performed a Wingate Anaerobic Test (WAnT) for the legs and for the arms. All H subjects received prophylactic factor VIII treatment in the 24 h pretesting, and no test was performed in the presence of hemorrhage., Results: C were consistently stronger than H in all dynamic strength measures (e.g., elbow flexors: 0.47 +/- 0.15 vs 0.36 +/- 0.08 N x m x kg(-1) for C and H, respectively, P < 0.05). Anaerobic mean power was also higher in C compared with H in both upper and lower extremities (arms: 3.08 +/- 0.99 vs 2.22 +/- 0.46 W x kg(-1) for C and H, respectively; legs: 6.94 +/- 1.62 vs 5.54 +/- 1.03 W x kg(-1) for C and H, respectively, P < 0.05). Upper and lower extremity strength, as well as anaerobic power, increased with age in C but not in H. By using the Godin Leisure-Time Exercise Questionnaire, H were found to be much less active, especially in intense activities, compared with C., Conclusion: Children and adolescents with hemophilia are characterized by lower muscle strength and anaerobic power compared with age-matched controls. This may be related to their lower leisure-time activity.

Objectives: To determine whether survivors of surgery for coarctation of the aorta (CoA) have an excessive reliance on anaerobic metabolism during exercise., Background: Patients with peripheral vascular disease cannot increase blood flow to their muscles normally during exercise. Consequently they acquire an early, excessive reliance on anaerobic metabolism and have depression of the ventilatory anaerobic threshold (VAT) and of the slope of the oxygen consumption-work rate relationship (delta VO2/delta WR). We speculated that the capacity to augment blood flow to the lower extremities during exercise may be impaired after CoA surgery and would result in similar metabolic disturbances., Study Design: Progressive exercise tests were performed on 15 patients (ages 19 +/- 7 years; range, 10 to 32) after successful repair of CoA (residual resting gradient, 7.7 +/- 7.1 mm Hg; range, 0 to 18), 15 age- and sex-matched healthy control subjects, and 10 patients (ages 13 +/- 3 years; range, 10 to 20) who had undergone ligation of a patent ductus arteriosus., Results: The CoA patients' VAT averaged 14.8 +/- 3.8 ml O2/kg per minute versus 19.3 +/- 3.1 ml O2/kg per minute for the control subjects (p < 0.01), and their delta VO2/delta WR averaged 8.2 +/- 1.8 ml/watt compared with 10.1 +/- 1.4 ml/watt for control subjects (p < 0.01). Furthermore, 10 of 15 CoA patients had a VAT of less than 40% of predicted maximal oxygen consumption, and 9 of 16 had a delta VO2/delta WR of less than 8.7 ml O2/watt (generally accepted abnormal values). Patients with patent ductus arteriosus resembled the healthy control subjects with regard to anaerobic metabolism during exercise., Conclusions: Patients who have had CoA repairs commonly manifest an excessive reliance on anaerobic metabolism during exercise. This phenomenon may result from persistent blood flow abnormalities across the aortic arch during exercise, which may be present even after apparently successful surgery.

Energy expenditure during and after exercise is composed of aerobic and anaerobic bioenergetics and the energy demands of aerobic recovery. Current attempts to measure energy expenditure include an exercise oxygen uptake + oxygen debt (EPOC) measurement or, an oxygen deficit + exercise oxygen uptake measurement. This investigation illustrates how oxygen debt and oxygen deficit interpretation can effect a total energy expenditure measurement. It was hypothesized that the total energy expenditure for several intermittent bouts of exercise and recovery would be greater than for one bout of continuous exercise and recovery when equivalent work was compared. Exercise was performed under low-intensity and high-intensity conditions. Both oxygen debt and oxygen deficit methodology resulted in similar energy expenditure measurements for both intermittent and continuous exercise. This implies little to no recovery energy demand or considerable methodology errors. Differences in total energy expenditure were found when the oxygen deficit and parts of the oxygen debt (EPOC) were considered separate and independent (p < 0.05). These differences can be accounted for when the data are interpreted utilizing thermodynamic (2nd law) and engineering (in-series efficiency) concepts rather than the heat equivalent of carbohydrate oxidation (20.9 kJ equals one liter of O2). It is suggested that while oxygen uptake provides an excellent representation of aerobic metabolism during exercise and recovery, oxygen uptake may be an inadequate measure of the energetics of lactate production (fermentation). In application, energy expenditure differences appear realistic only for high-intensity, intermittent exercise rather than lower intensity exercise.

We studied the effects of anaerobic and aerobic training on lipoprotein concentrations in 45 healthy untrained men. Thirty-three subjects exercised four times per week during nine weeks on a bicycle ergometer. Sixteen trained with an intensity above the anaerobic threshold (blood lactate concentration > 4 mmol.l-1) and 17 trained with an intensity below the anaerobic threshold. In addition, twelve subjects served as controls. The calculated caloric expenditure of the two training groups was similar. In all three groups, total cholesterol, total high-density lipoprotein (HDL), HDL subfractions (HDL2, HDL3), and low-density lipoprotein (LDL) were measured. Training had a significant influence on HDL, HDL2, LDL/HDL, HDL2/HDL3, and cholesterol/HDL. With anaerobic training these variables changed in the opposite direction compared with aerobic training which influenced the lipoprotein profile in the desired direction. Cholesterol, HDL3, and LDL did not alter during the nine weeks of training. After nine weeks of training, the higher the blood lactate concentration during exercise (representing training intensity) was, the higher resting LDL/HDL ratio was found. The correlation between these two variables was highly significant. We conclude that training above the anaerobic threshold has no or even negative effects on blood lipoprotein profiles. Therefore, beneficial adaptations in lipoprotein profile must be achieved with moderate training intensities below the anaerobic threshold.

The purpose of this study was to characterize the aerobic and anaerobic capabilities of United States Cycling Federation cyclists in different categories. To determine aerobic and anaerobic power, 38 competitive road cyclists (32 males, 6 females) performed a VO2max test and a Wingate anaerobic test, respectively. Male cyclists in category II had the highest VO2max, both in absolute and relative terms. Their VO2max was 6% and 10% higher than category III and IV cyclists, respectively (4.98 +/- 0.14 vs 4.72 +/- 0.15 vs 4.54 +/- 0.12 l/min). A significant difference existed between category II and IV male cyclists (p < 0.05). VO2max for female cyclists (3.37 +/- 0.13 l/min) was significantly (p < 0.05) lower than those for males. The Wingate anaerobic test revealed that male cyclists in category II also had the highest anaerobic power output. The peak power output in category II, III and IV was 13.86 +/- 0.23, 13.55 +/- 0.25, and 12.80 +/- 0.41 W/kg, respectively. The mean power output in category II, III, and IV was 11.22 +/- 0.18, 11.06 +/- 0.15, and 10.40 +/- 0.30 W/kg, respectively. The difference in the mean power output between category II and IV was significant (p < 0.05). Female cyclists recorded significantly less peak and mean power output than their male counterparts (p < 0.05). However, when expressed relative to lean body mass, anaerobic power was similar for both sexes. No inter-correlation was found in any measurement between the aerobic and anaerobic power values. On the whole, category II male cyclists were characterized by higher aerobic and anaerobic power outputs.(ABSTRACT TRUNCATED AT 250 WORDS)

The objectives of this study were to determine the relationships of estimated active muscle mass and gender to anaerobic capacity, as measured by the peak oxygen deficit, and to compare these relationships with those for peak oxygen uptake (VO2peak). Fat-free leg volumes (FFLV), and one- and two-legged cycling peak oxygen deficit and VO2peak were determined in young, physically active men (N = 11) and women (N = 9). For men and women, mean (+/- SD) peak oxygen deficit for one-legged cycling (2.27 +/- 0.30 and 1.18 +/- 0.18 l) was 52% of that for two-legged cycling (4.40 +/- 0.62 and 2.25 +/- 0.28 l). For all subjects and both modes of exercise, there was a strong linear relation between peak oxygen deficit (1) and estimated active muscle mass (FFLV) (r = 0.94). This relation was the same in one- and two-legged cycling, but was different for men and women. For a given FFLV, the peak oxygen deficit was significantly higher (P < 0.05) in men than women by an average of 0.44 l. The relation of peak oxygen deficit to FFLV was significantly stronger than the relation of VO2peak to FFLV (r = 0.80). We conclude: (a) that the peak oxygen deficit is strongly related to the estimated active muscle mass during cycling; (b) that for a given estimated active muscle mass (FFLV), the peak oxygen deficit is higher in men than women; and (c) that the peak oxygen deficit is more strongly related than VO2peak to the estimated quantity of active muscle.

All-out exercise may not impair all central nervous system processes, such as those related to visual-motor abilities, and may actually prove stimulatory to such tasks allowing athletes and sports conditioning specialists to develop strategies to take advantage of/mitigate the effects of such exercise on athletic performance. Despite research indicating that visual-motor abilities play a critical role in athletic performance, research has primarily focused on the effect of all-out exercise on processes along the motor pathway, such as resultant force production or simple cognitive tasks. Such research has neglected to investigate the effect of all-out exercise on visual tasks. When investigations on visual tasks are forthcoming, they focus on prolonged aerobic exercise, which is not the primary metabolic pathway for all, or even the majority of sports. Sixty untrained males (experimental group; N = 30, control group; N = 30) completed a standardised six-item baseline sports vision test battery and one week later, the experimental participants returned to undertake a 30-second Wingate anaerobic test (30-WAnT) immediately followed by the same test battery. Significant (P < 0.05) improvements were found in accommodation facility, saccadic eye movement, speed of recognition, peripheral awareness and hand-eye coordination (P < 0.001 for all), but not visual memory (P = 0.242) following the 30-WAnT. Although the mechanisms underlying these improvements in visual task performance have not yet been studied, this study suggests that simple anaerobic all-out exercise does not cause central- or brain-based fatigue impairing the oculomotor system but may rather provide "excitability" of the underlying motor cortex, motoneurons and/or corticofugal connections utilised in visual task response. It appears that the sweeping improvements in visual task performance elucidate the need for an intense anaerobic warm-up when training visual skills and when visual skills form an integral part of athletic performance. [ABSTRACT FROM AUTHOR]

• Background and Aims The use of microarrays to characterize the transcript profile of Arabidopsis under various experimental conditions is rapidly expanding. This technique provides a huge amount of expression data, requiring bioinformatics tools to allow the proposal of working hypotheses. The aim of this study was to test the usefulness of this approach to examine the anaerobic response of Arabidopsis by evaluating the reliability of microarray data sets and by interrogation of microarray databases for the expression data of a set of anoxia-inducible genes.•Methods User-driven software tools that display large gene expression datasets onto diagrams of metabolic pathways were used. The Genevestigator software was used to explore the expression of anoxia-inducible genes throughout the life cycle of Arabidopsis as well as relative to plant organs. T-DNA tagged mutants for selected genes identified from our microarray analysis were searched in the Arabidopsis thaliana Insertion Database, looking for insertional mutants from the Salk collection.•Key Results The results indicate that microarray data can provide the basis for new hypotheses in the field of plant responses to anaerobiosis and also provide knowledge for a targeted screening of Arabidopsis mutants.•Conclusions Research on plant responses to anaerobiosis can enormously benefit from the microarray technology. [ABSTRACT FROM AUTHOR]