Aerobic and anaerobic energy during a 2-km race simulation in female rowers

The maximal aerobic power (VO2max) and maximal anaerobic capacity (AODmax) of 16 female rowers were compared to their peak aerobic power (VO2peak) and peak anaerobic capacity (AODpeak, respectively) during a simulated 2-km race on a rowing ergometer. Each subject completed three tests, which included a 2-min maximal effort bout to determine the AODmax, a series of four, 4-min submaximal stages with subsequent progression to VO2max and a simulated 2-km race. Aerobic power was determined using an open-circuit system, and the accumulated oxygen deficit method was used to calculate anaerobic capacities from recorded mechanical power on a rowing ergometer. The average VO2peak (3.58 l min(-1)), which usually occurred during the last minute of the race simulation, was not significantly different (P > 0.05) from the VO2max (3.55 l min(-1)). In addition, the rowers' AODmax (3.40 l) was not significantly different (P > 0.05) from their AODpeak (3.50 1). The average time taken for the rowers to complete the 2-km race simulation was 7.5 min, and the anaerobic system (AODpeak) accounted for 12% of the rowers' total energy production during the race.     

厌氧菌和需氧菌性阴道混合感染发病调查

目的对妇女厌氧菌和需氧菌性阴道混合感染发病进行调查分析。方法分别采用Donders高倍镜湿片镜检法和细菌预成酶快速检测法对257例患者进行联合检测。结果257例患者中共检出单纯的需氧菌性阴道感染患者52例,占总人数的20．2％,检出单纯的厌氧菌阴道感染患者125例,占总人数的48．6％,检出厌氧菌和需氧菌性阴道混合感染患者67例,占总人数的26．1％,检出其他感染患者13例,占总人数的5％,经统计学分析,患者的厌氧菌和需氧菌性阴道混合感染的检出率差异无统计学意义（P〉0．05）。结论厌氧菌和需氧菌性阴道混合感染,可以给临床医生应采取合理有效的措施进行及时治疗,防止阴道上行感染的发生。     

Investigation of granulation of a mixture of suspended anaerobic and aerobic cultures under alternating anaerobic/microaerobic/aerobic conditions

This is the first granulation study except Ferguson [Ferguson LN. Anaerobic codigestion of aircraft deicing fluid and microaerobic studies. M.S. Thesis. Milwaukee, WI, USA: Marquette University; 1999] to develop coupled granules by using a mixture of suspended anaerobic and aerobic cultures exposed to alternating cyclic anaerobic/microaerobic/aerobic conditions. Coupled granules with median sizes of 1.28–1.86 mm and settling velocities of 31–39 m/h were developed, which were comparable to those of both anaerobic and aerobic granules. Coupled granules displayed noteworthy specific methanogenic activity (SMA) and specific oxygen uptake rate (SOUR) as 14–42 mL CH₄/g VSS h and 6–47 mg DO/g VSS h, respectively, indicating that they were composed of both anaerobic and aerobic cultures.     

Muscle metabolic profile and oxygen transport capacity as determinants of aerobic and anaerobic thresholds

Aerobic and anaerobic thresholds determined by different methods in repeated exercise tests were correlated with cardiorespiratory variables and variables of muscle metabolic profile in 33 men aged 20-50 years. Aerobic threshold was determined from blood lactate, ventilation, and respiratory gas exchange by two methods (AerT1 and AerT2) and anaerobic threshold from venous lactate (AnTLa), from ventilation and gas exchange (AnTr) and by using the criterion of 4 mmol.1(-1) of venous lactate (AnT4mmol). In addition to ordinary correlative analyses, applications of LISREL models were used. The 8 explanatory variables chosen for the regression analyses were height, relative heart volume, relative diffusing capacity of the lung, muscle fiber composition, citrate synthase (CS) and succinate dehydrogenase activities, the lactate dehydrogenase--CS ratio, and age. They explained 58% of the variation in AerT1, 73.5% that of AerT2, 71% that of AnTr, 74.5% that of AnTLa, and 67.5% that of AnT4mmol.AerT and AnT alone explained 77% of the variation in each other. Both AerT and AnT were determined mainly by a muscle metabolic profile, with the CS activity of vastus lateralis as the strongest determinant. The factor 'submaximal endurance' which was measured with AerT and AnT seemed to be slightly more closely connected to 'muscle metabolic profile' than was 'maximal aerobic power' (= VO2max), but both also correlated strongly with each other (r = 0.92).     

Comparison of aerobic and anaerobic degradation of municipal solid waste in bioreactor landfills

Two landfill bioreactors were operated under aerobic and anaerobic conditions in a thermo-insulated room at a constant temperature of 32 °C. Reactors were filled with 19.5 kg of shredded synthetic solid waste prepared according to the average municipal solid waste compositions determined in Istanbul and operated under wet-tomb management strategy by using leachate recirculation. Aerobic conditions in the reactor were developed by using an air compressor. The results of experiments indicated that aerobic reactor had higher organic, nitrogen, phosphorus and alkali metal removal efficiencies than the anaerobic one. Furthermore, stabilization time considerably decreased when using aerobic processes with leachate recirculation compared to the anaerobic system with the same recirculation scheme.     

Blood lactate during constant-load exercise at aerobic and anaerobic thresholds

Venous blood lactate concentrations [1ab] were measured every 30 s in five athletes performing prolonged exercise at three constant intensities: the aerobic threshold (Thaer), the anaerobic threshold (Than) and at a work rate (IWR) intermediate between Thaer and Than. Measurements of oxygen consumption (VO2) and heart rate (HR) were made every min. Most of the subjects maintained constant intensity exercise for 45 min at Thaer and IWR, but at Than none could exercise for more than 30 min. Relationships between variations in [1ab] and concomitant changes in VO2 or HR were not statistically significant. Depending on the exercise intensity (Thaer, IWR, or Than) several different patterns of change in [1ab] have been identified. Subjects did not necessarily show the same pattern at comparable exercise intensities. Averaging [1ab] as a function of relative exercise intensity masked spatial and temporal characteristics of individual curves so that a common pattern could not be discerned at any of the three exercise levels studied. The differences among the subjects are better described on individual [1ab] curves when sampling has been made at time intervals sufficiently small to resolve individual characteristics.     

Characterization of strain HY99, a novel microorganism capable of aerobic and anaerobic degradation of aniline

We have characterized a novel microorganism, strain HY99, which is capable of aerobic and anaerobic degradation of aniline. Strain HY99 was found to aerobically metabolize aniline via catechol and 2-hydroxymuconic semialdehyde intermediates, and to transform aniline via p-aminobenzoate in anaerobic environments. Physiological and biochemical tests revealed that strain HY99 was most similar to Delftia acidovorans, but unlike D. acidovorans, strain HY99 was able to metabolize aniline under anaerobic conditions linked with nitrate reduction. Phylogenetic analysis based on 16S rDNA sequencing also revealed that strain HY99 was closely related to D. acidovorans, with 96% overall similarity.     

Batch culture enrichment of ANAMMOX populations from anaerobic and aerobic seed cultures

Discharge of nitrate and ammonia rich wastewaters into the natural waters encourage eutrophication, and contribute to aquatic toxicity. Anaerobic ammonium oxidation process (ANAMMOX) is a novel biological nitrogen removal alternative to nitrification-denitrification, that removes ammonia using nitrite as the electron acceptor. The feasibility of enriching the ANAMMOX bacteria from the anaerobic digester sludge of a biomethanation plant treating vegetable waste and aerobic sludge from an activated sludge process treating domestic sewage is reported in this paper. ANAMMOX bacterial activity was monitored and established in terms of nitrogen transformations to ammonia, nitrite and nitrate along with formation of hydrazine and hydroxylamine.     

Estimation of hand forces and propelling efficiency during front crawl swimming with hand paddles

The aim of the study was to investigate possible modifications caused by hand paddles in the relative contribution of the lift and drag forces of the hand and in the propelling efficiency, during front crawl swimming. Eight female swimmers swam 25 m with maximal intensity without paddles, with small (116 cm(2)) and with large paddles (268 cm(2)). Four cameras operating at 60 Hz were used to record the images and the Ariel Performance Analysis System was used for the digitisation. The results showed that, although during swimming with hand paddles the hand's velocity decreased, the greater propulsive area of the hand paddle caused an increase in the drag, lift, resultant and effective forces of the hand. However, the relative contribution of lift and drag forces on swimming propulsion was not modified, nor was the direction of the resultant force. Hand paddles also increased the propelling efficiency, the stroke length and the swimming velocity, mainly because of the larger propulsive areas of the hand in comparison with free swimming. However, the significant decrease of the stroke rate, might argue the effectiveness of hand paddle training, particularly when large paddles are used in front crawl swimming.     

Rapid detection of a gfp-marked Enterobacter aerogenes under anaerobic conditions by aerobic fluorescence recovery

A gfp- and kanamycin-resistance gene-containing plasmid pUCGK was successfully constructed and transformed into Enterobacter aerogenes to develop a rapid GFP-based method for quantifying the bacterial concentration under anaerobic conditions for production of biohydrogen. Since the use of GFP as a molecular reporter is restricted by its requirement for oxygen in the development of the fluorophore, fluorescence detection for the fluorescent E. aerogenes grown anaerobically for hydrogen production was performed by developing a method of aerobic fluorescence recovery (AFR) of the anaerobically expressed GFP. By using this AFR method, rapid and non-disruptive cell quantification of E. aerogenes by fluorescence density was achieved for analyzing the hydrogen production process.     

Inter-individual variability and pattern recognition of surface electromyography in front crawl swimming

Variability of electromyographic (EMG) recordings is a complex phenomenon rarely examined in swimming. Our purposes were to investigate inter-individual variability in muscle activation patterns during front crawl swimming and assess if there were clusters of sub patterns present. Bilateral muscle activity of rectus abdominis (RA) and deltoideus medialis (DM) was recorded using wireless surface EMG in 15 adult male competitive swimmers. The amplitude of the median EMG trial of six upper arm movement cycles was used for the inter-individual variability assessment, quantified with the coefficient of variation, coefficient of quartile variation, the variance ratio and mean deviation. Key features were selected based on qualitative and quantitative classification strategies to enter in a k-means cluster analysis to examine the presence of strong sub patterns. Such strong sub patterns were found when clustering in two, three and four clusters. Inter-individual variability in a group of highly skilled swimmers was higher compared to other cyclic movements which is in contrast to what has been reported in the previous 50 years of EMG research in swimming. This leads to the conclusion that coaches should be careful in using overall reference EMG information to enhance the individual swimming technique of their athletes.     

A definition and systems view of anaerobic capacity

The purpose of this paper is both to define terms used in exercise physiology, i.e. anaerobic capacity, anaerobic work capacity and anaerobic potential, and develop a systems perspective of anaerobic capacity. Philosophical argument is used to support the proposed definitions and systems view, which is an approach to assist in the universal acceptance of such terms amongst scientific investigators, coaches and athletes, and provide a focus on physiological mechanisms associated with anaerobic capacity which may be the subject of future investigation.     

Maximal oxygen uptake, anaerobic threshold and running economy in women and men with similar performances level in marathons

Sex differences in running economy (gross oxygen cost of running, C_R), maximal oxygen uptake (VO_2max), anaerobic threshold (Th_an), percentage utilization of aerobic power (% VO_2max), and Th_an during running were investigated. There were six men and six women aged 20–30 years with a performance time of 2 h 40 min over the marathon distance. The VO_2max, Th_an, and CR were measured during controlled running on a treadmill at 1° and 3° gradient. From each subject's recorded time of running in the marathon, the average speed (v _M) was calculated and maintained during the treadmill running for 11 min. The VO_{2 max} was inversely related to body mass (m _b), there were no sex differences, and the mean values of the reduced exponent were 0.65 for women and 0.81 for men. These results indicate that for running the unit ml·kg^–0.75·min^–1 is convenient when comparing individuals with different m _b. The VO_2max was about 10% (23 ml·kg^–0.75·min^–1) higher in the men than in the women. The women had on the average 10–12 ml·kg^–0.75·min^–1 lower VO₂ than the men when running at comparable velocities. Disregarding sex, the mean value of C_R was 0.211 (SEM 0.005) ml·kg^–1·m^–1 (resting included), and was independent of treadmill speed. No sex differences in Th_an expressed as % VO_2max or percentage maximal heart rate were found, but Than expressed as VO₂ in ml·kg^–0.75·min^–1 was significantly higher in the men compared to the women. The percentage utilization of f _emax and concentration of blood lactate at v _M was higher for the female runners. The women ran 2 days more each week than the men over the first 4 months during the half year preceding the marathon race. It was concluded that the higher VO_2max and Th_an in the men was compensated for by more running, superior C_R, and a higher exercise intensity during the race in the performance-matched female marathon runners.     

Effect of oral creatine ingestion on parameters of the work rate-time relationship and time to exhaustion in high-intensity cycling

The relationship between work rate (W˙) and time to exhaustion (t) during intense exercise is commonly described by either a hyperbolic function (NLin), t=W ^′/(W˙−W˙ _cp), or by its linear equivalent (LinW) W _lim =W ^′+W˙ _cp(t). The parameter W˙<INF _</INF>cp (critical power) has been described as an inherent characteristic of the aerobic energy system, while W ′ has been shown to be a ralid estimate of anaerobic work capacity. Recent studies have demonstrated that oral supplementation of creatine monohydrate (CrH₂O) increases total muscle creatine stores, and have linked these increases to improved performances in intense intermittent exercise. This study was conducted to determine the effect of CrH₂O supplementation on estimates of W ′ and W˙<INF _</INF>cp derived from the NLin and LinW equations, and to determine the effect of CrH₂O on t in exhaustive constant power exercise of different intensities. Fifteen active but untrained university students completed three phases of testing on a cycle ergometer: (1) familiarization, three learning trials, (2) baseline determination of W ′ and W˙<INF _</INF>cp, four bouts performed at a W˙ selected to elicit fatigue in 90–600 s, and (3) experimental determination of W ′ and W˙ _cp, four bouts performed at the same W˙ as baseline, but performed after 5 days of ingesting either a placebo (4 × 6 g of glucose/day) or CrH₂O (4 × 5 g of CrH₂O and 1 g glucose/day). Testing was administered in a double-blind manner. Analyses of covariance revealed a significant effect for CrH₂O on both estimates of W ′ (NLin, P=0.04; LinW, P<0.01), but not on estimates of W˙ _cp (NLin, P=0.37; LinW; P=0.30). Within groups, t was significantly different for only CrH₂O at the two highest W˙s (P=0.04). It is concluded that oral ingestion of CrH₂O increases estimates of W ′ due to an improved t at the shorter, more intense exercise bouts. Accepted: 1 September 1997     

Relationship between aerobic fitness and metabolic power metrics in elite male soccer players

The aim was to assess the relationship between aerobic fitness and metabolic power metrics in elite male soccer players, and the possible differences that playing positions might impose during match play over new metabolic power metrics. Sixty-two elite professional male soccer players (13 central backs, 13 side backs, 22 midfielders, and 14 forwards) took part in the study. Players were monitored during eleven months of full training (including pre-season and in-season) and over all official matches (Serie A matches, Italy Cup matches). Aerobic fitness tests were conducted one week after the start of the preseason, and 8, 24 and 36 weeks after the beginning of the Championship. Players’ aerobic fitness and metabolic power metrics were considered as the mean of all seasonal testing and of pooling data of 38 championship matches and 3 or 6 Italy Cup matches for all the calculations respectively. The velocity at 4 mmol·L^-1 (VL₄) was significantly related to metabolic power metrics match variables with correlation ranging from trivial to very large (r = 0.32 to r = 0.89). Receiver-operating-characteristic (ROC) analysis showed that speed at VL₄ was sensitive in detecting high metabolic power distance (HMPD) changes in all but central back players as revealed by area under the curve (central back .78, 95%CI .47 to .95; full back .93, 95%CI .64 to 0.99; midfielder .88, 95%CI .67 to 0.98; forward .90, 95%CI .62 to 0.99). This study’s findings provide further evidence for the ecological validity of aerobic fitness in elite male soccer players. Players having a HMPD cut-off equal to or higher than > 1450 m for central backs, > 1990 m for full backs, > 2170 m for midfielders and > 1670 m for forwards may be considered as possessing superior aerobic fitness status. In light of this study’s findings, the VL₄ test may be considered a valid test to evaluate meaningful information for direct generic aerobic training in soccer players.     

The relationship of aerobic capacity,anaerobic peak power and experience to performance in CrossFit exercise

CrossFit is becoming increasingly popular as a method to increase fitness and as a competitive sport in both the Unites States and Europe. However, little research on this mode of exercise has been performed to date. The purpose of the present investigation involving experienced CrossFit athletes and naïve healthy young men was to investigate the relationship of aerobic capacity and anaerobic power to performance in two representative CrossFit workouts: the first workout was 12 minutes in duration, and the second was based on the total time to complete the prescribed exercise. The participants were 32 healthy adult males, who were either naïve to CrossFit exercise or had competed in CrossFit competitions. Linear regression was undertaken to predict performance on the first workout (time) with age, group (naïve or CrossFit athlete), VO₂max and anaerobic power, which were all significant predictors (p < 0.05) in the model. The second workout (repetitions), when examined similarly using regression, only resulted in CrossFit experience as a significant predictor (p < 0.05). The results of the study suggest that a history of participation in CrossFit competition is a key component of performance in CrossFit workouts which are representative of those performed in CrossFit, and that, in at least one these workouts, aerobic capacity and anaerobic power are associated with success.     

Divergent roles of RpoS in Escherichia coli under aerobic and anaerobic conditions

Escherichia coli exhibited different levels of rpoS expression and general stress resistance under aerobiosis and anaerobiosis. Expression measured using reporter gene fusions and protein levels was lower under anaerobic conditions. Consistent with earlier findings, rpoS mutants were selected in aerobic nutrient-limited cultures but rpoS mutants were not enriched under anaerobiosis. This result suggested that, despite its decreased level, RpoS had a function under anaerobic conditions not essential under aerobiosis. Competition experiments between rpoS(+) and rpoS bacteria confirmed the advantage conferred by RpoS under anaerobiosis. In contrast, stress resistance assays suggested RpoS made a greater contribution to general stress resistance under aerobiosis than anaerobiosis. These results indicate a significant, but different role of RpoS in aerobic and anaerobic environments.     

Association of regulatory genes polymorphisms with aerobic and anaerobic performance of athletes

The aim of study was to investigate an allelic distribution of PPARA (G/C polymorphism), PPARG (Pro/Ala), PPARD (+294T/C) and PGCIA (Gly482Ser) genes in rowers (n=205) and controls (n=659), and to find correlation between genotypes and physiological parameters. Genotyping was performed by restriction fragment length polymorphism analysis. Physiological parameters were evaluated by PM 3 Rower Ergometer and MetaMax 3B Gas Analyzer. The frequencies ofPPARA G (90.1% vs. 83.6%) and PPARG Ala (23.1% vs. 16.2%) alleles in elite athletes, and of PPARD C (19.1% vs. 10.5%) and PGC1A Gly (75.4% vs. 66.5%) alleles in sub-elite athletes were significantly higher than in controls. Moreover, PPARA G (when oxygen pulse was measured) and PGC 1A Gly (when maximal aerobic power and anaerobic threshold (%) of VO2max were measured) alleles were associated with high values of aerobic performance. Thus, PPARA G, PPARG Ala, PPARD C and PGCIA Gly alleles can be considered as genetic markers associated with enhanced physical performance.     

Validity of different EMG analysis methods to identify aerobic and anaerobic thresholds in speed skaters

Purpose: This study aimed to assess the validity of the first (EMGth1) and second (EMGth2) breakpoints in the EMG signal during skating. Scope: Ten well-trained long track speed skaters performed a maximal incremental skating test on a slide board. EMG signals from six lower limb muscles were recorded during the last 15 s of each stage and converted to Root Mean Square for determination EMGth1 and EMGth2 using mathematical (2 and 3 linear regressions) and visual methods. Conclusions: EMGth1 had a low detection rate (<50%) while EMGth2 could be identified visually in > 80% of cases, in 85% of cases using 2-lines and 63% using 3-lines regression. Quads (VL + VM) and Gluts (GM + GMd) had the highest EMGth2 detection rate for all methods (>70%). EMGth2 from Quads and Gluts detected by the 2-lines and 3-lines regression were not different than the second ventilatory threshold (VT2) (p > 0.05), while the visual method overestimated VT2 (p < 0.01). EMGth2 detected from Quads by the 2-lines regression method presented better correlation with VT2 stage (r = 0.91), lowest bias, and limit of agreement. We conclude that EMG is a valid non-invasive method to detect VT2 during skating when using a mathematical method to determine EMGth2.