Submaximal oxygen uptake kinetics, functional mobility, and physical activity in older adults with heart failure and reduced ejection fraction

Background Submaximal oxygen uptake measures are more feasible and may better predict clinical cardiac outcomes than maximal tests in older adults with heart failure （HF）. We examined relationships between maximal oxygen uptake, submaximal oxygen kinetics, fianctional mobility, and physical activity in older adults with HF and reduced ejection fraction. Methods Older adults with HF and reduced ejection fraction （n = 25, age 75 ：i： 7 years） were compared to 25 healthy ageand gender-matched controls. Assessments included a maximal treadmill test for peak oxygen uptake （VO2p^ak）, oxygen uptake kinetics at onset of and on recovery from a submaximal treadmill test, functional mobility testing [Get Up and Go （GUG）, Comfortable Gait Speed （CGS）, Unipedal Stance （US）], and self-reported physical activity （PA）. Results Compared to controls, HF had worse performance on GUG, CGS, and US, greater delays in submaximal oxygen uptake kinetics, and lower PA. In controls, VO2peak was more strongly associated with functional mobility and PA than submaximal oxygen uptake kinetics. In HF patients, submaximal oxygen uptake kinetics were similarly associated with GUG and CGS as VO2peak, but weakly associated with PA. Conclusions Based on their mobility performance, older HF patients with reduced ejection fraction are at risk for adverse functional outcomes. In this population, submaximal oxygen uptake measures may be equivalent to VO2 peak in predicting functional mobility, and in addition to being more feasible, may provide better insight into how aerobic function relates to mobility in older adults with HF.

Relationship between peak oxygen uptake and regional body composition in Japanese subjects

Purpose： To investigate the link between peak oxygen uptake and regional body composition by dual energy X-ray absorptiometry （DEXA） in Japanese subjects. Methods： A total of 93 men （42.2 ± 12.3 years old） and 106 women （43.5 ± 12.3 years old） were enrolled in this cross-sectional investigation study. Peak oxygen uptake was measured by the breath-by-breath method. Regional body composition i.e., body fat mass, lean body mass, and body fat percentage was evaluated using DEXA. In addition, metabolic risk parameters were also evaluated. Results： Peak oxygen uptake was 37.6± 8.7 mL/kg/min in men and 31.1 ± 6.4 mL/kg/min in women, and decreased with age in both genders. Peak oxygen uptake was significantly correlated with total body fat percentage （men： r = -0.684, p 〈 0.0001; women： r = -0.681, p 〈 0.0001）. These associations remained even after adjusting for age and total lean body mass. However, peak work rate was positively and significantly correlated with leg lean body mass. Conclusion： Peak oxygen uptake was closely correlated with total body fat percentage in both genders. Aerobic exercise as well as leg resistance training might be useful for improving peak oxygen uptake in Japanese subjects. Copyright

Oxygen uptake response to switching stairs exercise by non-parametric modeling

Oxygen uptake plays a crucial role in the evaluation of endurance performance during exercise and is extensively utilized for metabolic assessment. This study records the oxygen uptake during the exercise phase (i.e., ascending or descending) of the stair exercise, utilizing an experimental dataset that includes ten participants and covers various exercise periods. Based on the designed experiment protocol, a non-parametric modeling method with kernel-based regularization is generally applied to estimate the oxygen uptake changes during the switching stairs exercise, which closely resembles daily life activities. The modeling results indicate the effectiveness of the non-parametric modeling approach when compared to fixed-order models in terms of accuracy, stability, and compatibility. The influence of exercise duration on estimated fitness reveals that the model of the phase-oxygen uptake system is not time-invariant related to respiratory metabolism regulation and muscle fatigue. Consequently, it allows us to study the humans’ conversion mechanism at different metabolic rates and facilitates the standardization and development of exercise prescriptions.

Oxygen uptake during the last bouts of exercise incorporated into high-intensity intermittent cross-exercise exceeds the V_ O2max of the same exercise mode

Oxygen uptake(V O_(2))was measured during a non-exhaustive high-intensity intermittent cross-exercise(HIICE)protocol consisting of four alternating bouts of 20 s running(R)and three bouts of bicycle exercise(BE)at~160%and~170%maximal oxygen uptake(V O_(2)max),respectively,with 10 s between-bout rests(sequence R-BE-R-BER-BE-R).The V O_(2) during the last BE([52.2±5.0]mL⋅kg^(-1)⋅min^(-1))was significantly higher than the V O_(2)max of the BE([48.0±5.4]mL⋅kg^(-1)⋅min^(-1),n=30)and similar to that of running.For clarifying the underlying mechanisms,a corresponding HIICE-protocol with BE and arm cranking ergometer exercise(AC)was used(sequence AC-AC-BE-AC-BE-AC-AC-BE).In some experiments,thigh blood flow was occluded by a cuff around the upper thigh.Without occlusion,the V O_(2) during the AC([39.2±7.1]mL⋅kg^(-1)⋅min^(-1)[6th bout])was significantly higher than the V O_(2)max of AC([30.2±4.4]mL⋅kg^(-1)⋅min^(-1),n=7).With occlusion,the corresponding V O_(2)([29.8±3.9]mL⋅kg^(-1)⋅min^(-1))was reduced to that of the V O_(2)max of AC and significantly less than the V O_(2) without occlusion.These findings suggest that during the last bouts of HIICE may exceed the of the specific exercise,probably because it is a summation of the V O_(2) for the ongoing exercise plus excess post-oxygen consumption(EPOC)produced by the previous exercise with a higher V O_(2)max.

Impact of Novel Pulsed Electromagnetic Field Device on Competitive Athlete Performance

The interaction of pulsed electromagnetic fields (PEMF) with the human body may result in a variety of positive outcomes including analgesia, enhanced healing, chondroprotection, cognitive improvement and better quality of life. Previous human studies have also revealed the potential of PEMF to enhance muscle function and athletic performance. To further evaluate this potential, an open label pilot study was conducted with 19 competitive cyclists who repeatedly participated in 63 training routes. Cyclist performance was tracked before and during use of a novel and portable PEMF device that is worn as a wristband. Comparison of performance before and during use of the wristband revealed a significant association with improved muscle power. The odds ratio was 3.02 (P < 0.01) for experiencing increased muscle power while wearing the PEMF device. Among the cycling routes in which an increase was observed, the average increase in power was about 9.8%. The data suggests the novel PEMF technology may be a safe and effective therapeutic approach for improved physical performance and likely involves improved oxygen delivery due to reduced rouleaux (erythrocyte aggregation). These results warrant further investigation comprising larger studies and additional outcomes.

Immobilization of activated sludge using improved polyvinyl alcohol (PVA) gel

The microbial immobilization method using polyvinyl alcohol （PVA） gel as an immobilizing material was improved and used for entrapment of activated sludge. The oxygen uptake rate （OUR） was used to characterize the biological activity of immobilized activated sludge. Three kinds of PVA-immobilized particles of activated sludge, that is, PVA-boric acid beads, PVA-sodium nitrate beads and PVA-orthophosphate beads were prepared, and their biological activity was compared by measuring the OUR value. The bioactivity of both autotrophic and heterotrophic microorganisms of activated sludge was determined using different synthetic wastewater media （containing 250 mg/L COD and 25 mg/L NH4^＋ -N）. The experimental results showed that the bioactivity and stability of the three kinds of immobilized activated sludge was greatly improved after activation. With respect of the bioactivity and the mechanical stability, the PVA-orthophosphate method may be a promising and economical technique for microbial immobilization.

Biodegradability of soil water soluble organic carbon extracted from seven different soils

Water soluble organic carbon （WSOC） is considered the most mobile and reactive soil carbon source and its characterization is an important issue for soil ecology study. A biodegradability test was set up to study WSOC extracted from 7 soils differently managed. WSOC was extracted from soil with water （soil/water ratio of 1：2, W/V） for 30 min, and then tested for biodegradability by a liquid state respirometric test. Result obtained confirmed the finding that WSOC biodegradability depended on the both land use and management practice. These results suggested the biodegradability test as suitable method to characterize WSOC, and provided useful information to soil fertility.

Heart rate variability to assess ventilatory thresholds in professional basketball players

Purpose: The aim of this study was to determine if heart rate variability(HRV) during incremental test could be used to estimate ventilatory threshold(VT) in professional basketball players, with sufficient precision to be used in their training. Furthermore, the second aim was to analyse the association between HRV and 3 methods of VT determination by gas analysis.Methods: Twenty-four professional basketball players(age: 23.4 ± 4.9 years; height: 195.4 ± 9.8 cm; body mass: 92.2 ± 11.9 kg) performed an incremental running test to exhaustion. First ventilatory threshold(VT1) was determined by ventilatory equivalent(VE) and HRV and second ventilatory threshold(VT2) was determined by 3 methods of gases analysis(V-slope, VE and gas exchange ratio(R), and HRV). Pearson's coefficient(r) was used to detect differences between data and the strength of each relationship. The mean of absolute differences and Bland–Altman analysis were used to evaluate whether there was agreement.Results: The results showed no significant differences in HR and oxygen consumption(VO2) at VT1 between the 2 methods. Furthermore, no significant differences among the methods of gases analysis and HRV were observed in speed, HR, and VO2 at VT2. Moreover, VTs estimated using HRV and gas methods were significantly correlated. Correlation in HR values was higher between R and HRV(r = 0.96) and VE and HRV(r = 0.96) than V-slope and HRV(r = 0.90).Conclusion: These findings provide a practical, inexpensive approach for evaluating specific training loads when determining VT2 in basketball players. Therefore, HRV is an alternative method to determine VT2 without the application of expensive technology that limits its use to laboratories.

Effects of 3 months of full-court and half-court street basketball training on health profile in untrained men

Purpose: The aim of the present study was to investigate whether street basketball organized as 3 v 3 on either a half court(HC) with 1 basket or a full court(FC) with 2 baskets could improve fitness and health profiles of untrained men after 3 months of supervised training.Methods: Thirty-five untrained men(aged 20—42 years) completed the pre-and post-intervention testing(FC: n = 13, HC: n = 12, CO(control):n = 10). The training attendance was 2.0 ± 0.4 and 1.9 ± 0.3 times per week in FC and HC, respectively. Mean heart rate(HR) was 83.8 ± 6.0 percent of maximal heart rate(%HR_(max)) and 84.5 ± 2.9 %HR_(max) in FC and HC, respectively.Results: The 3 months of street basketball training on an FC with 2 baskets increased maximal oxygen uptake(2.4 mL/min/kg(95% confidence interval(CI): 1.0—3.9)), time to exhaustion(47 s(95%CI: 26—67)), lean body mass(0.8 kg(95%CI: 0.1—1.5)), and bone mineral density(0.021 g/cm^2(95%CI: 0.011—0.031)), whereas mean arterial pressure(—5.6 mm Hg(95%CI: —7.5 to 3.7)), body fat percentage(—1.6%,(95%CI: —2.5 to —0.7)), heart rate(—18 bpm(95%CI: —24 to —12)), and blood lactate(median: —1.4 mmol/L(interquartile range: —1.5 to —0.6)) during submaximal running were lowered. The changes were less pronounced after the training period when playing on an HC with 1 basket, but increases in maximal oxygen uptake(1.6 mL/min/kg(95%CI: —0.1 to 3.3)), time to exhaustion(28 s(95%CI: 9—47)), lean body mass(1.3 kg(95%CI: 0.3—2.4)), and lower body fat percentage(—0.9%(95%CI: —1.9 to —0.1)) were observed in this group.Conclusion: Three months of 3 v 3 street basketball training improved fitness and led to broad-spectrum improvements in variables related to overall health profile, with the most marked effects observed when playing on an FC with 2 baskets.

Test Verification and Design of the Bicycle Frame Parameters

Research on design of bicycles is concentrated on mechanism and auto appearance design, however few on matches between the bike and the rider. Since unreasonable human-bike relationship leads to both riders＇ worn-out joints and muscle injuries, the design of bicycles should focus on the matching. In order to find the best position of human-bike system, simulation experiments on riding comfort under different riding postures are done with the lifemode software employed to facilitate the cycling process as well as to obtain the best position and the size function of it. With BP neural network and GA, analyzing simulation data, conducting regression analysis of parameters on different heights and bike frames, the equation of best position of human-bike system is gained at last. In addition, after selecting testers, customized bikes based on testers＇ height dimensions are produced according to the size function. By analyzing and comparing the experimental data that are collected from testers when riding common bicycles and customized bicycles, it is concluded that customized bicycles are four times even six times as comfortable as common ones. The equation of best position of human-bike system is applied to improve bikes＇ function, and the new direction on future design of bicycle frame parameters is presented.

Immersible ergocycle prescription as a function of relative exercise intensity

Purpose: The purpose of this study was to establish the relationship between various expressions of relative exercise intensity percentage of maximal oxygen uptake(%VO_(2max)), percentage of maximal heart rate(%HR_(max)), %VO_2 reserve(%VO_2R), and %HR reserve(%HRR)) in order to obtain the more appropriate method for exercise intensity prescription when using an immersible ergocycle(IE) and to propose a prediction equation to estimate oxygen consumption(VO_2) based on IE pedaling rate(rpm) for an individualized exercise training prescription.Methods: Thirty-three healthy participants performed incremental exercise tests on IE and dryland ergocycle(DE) at equal external power output(Pext). Exercise on IE began at 40 rpm and was increased by 10 rpm until exhaustion. Exercise on DE began with an initial load of 25 W and increased by 25 W/min until exhaustion. VO_2 was measured with a portable gas analyzer(COSMED K4b^2) during both incremental tests. On IE and DE, %VO_2R, %HRmax, and %HRR at equal Pext did not differ(p > 0.05).Results: The %HRR vs. %VO_2R regression for both IE and DE did not differ from the identity line %VO_2R IE = 0.99 × HRR IE(%) + 0.01(r^2= 0.91, SEE = 11%); %VO_2R DE = 0.94 × HRR DE(%) + 0.01(r^2= 0.94, SEE = 8%). Similar mean values for %HRmax, %VO_2R, and %HRR at equal Pext were observed on IE and DE. Predicted VO_2 obtained according to rpm on IE is represented by: VO_2(L/min) = 0.000542 × rpm2-0.026 × rpm + 0.739(r = 0.91, SEE = 0.319 L/min).Conclusion: The %HRR–%VO_2R relationship appears to be the most accurate for exercise training prescription on IE. This study offers new tools to better prescribe, control, and individualize exercise intensity on IE.

New insights in paediatric exercise metabolism

Research in paediatric exercise metabolism has been constrained by being unable to interrogate muscle in vivo.Conventionally,research has been limited to the estimation of muscle metabolism from observations of blood and respiratory gases during maximal or steady state exercise and the analysis of a few muscle biopsies taken at rest or post-exercise.The purpose of this paper is to review how the introduction of 31p-magnetic resonance spectroscopy and breath-by-breath oxygen uptake kinetics studies has contributed to current understanding of exercise metabolism during growth and maturation.Methodologically robust studies using 31p-magnetic resonance spectroscopy and oxygen uptake kinetics with children are sparse and some data are in conflict.However,it can be concluded that children respond to exercise with enhanced oxygen utilization within the myocyte compared with adults and that their responses are consistent with a greater recruitment of type I muscle fibres.Changes in muscle metabolism are age,maturation- and sex-related and dependent on the intensity of the exercise challenge.The introduction of experimental models such as "priming exercise" and "work-to-work" transitions provide intriguing avenues of research into the mechanisms underpinning exercise metabolism during growth and maturation.Copyright(c)2012,Shanghai University of Sport.Production and hosting by Elsevier B.V.All rights reserved.

Somatotype Components, Aerobic Fitness and Grip Strength in Kuwaiti Males and Females

Introduction and Objective: We investigated the association of endo-, meso- and ecto-morphic components of somatotype with aerobic power, mid-trunk flexibility and grip strength. Methods: Healthy male (n = 226) and female (n = 86) subjects, aged 9 - 55 years, sedentary (n = 154) or participating in sports (n = 158) were studied. Anthro-pometrics (height, weight, 8 skin folds, arm and calf circumferences, elbow and knee diameters), maximal exercise O2 uptake, mid trunk flexibility, right and left grip strength were measured. Results: Sedentary adult females were endomorphic with mesomorph tendency, and had low aerobic power (27.8 ± 0.6 ml/Kg·min) and low (48.7 ± 1 Kg) grip strength. Sedentary males (young and adults) and Sports adult males were mesomorph with endomorphic tendency. Sports junior males were balanced mesomorph. Aerobic power was 54.1 ± 0.9 ml/Kg·min in sports young males, 53.8 ± 0.9 ml/Kg·min in sports adult males, 41.2 ± 4.3 ml/Kg·min in sedentary young males, and 39.5 ± 1 ml/Kg·min in sedentary adult males. Grip strength was 89.9 ± 1.7 Kg in sports adult males, 86.7 ± 2 Kg in sedentary adult males, 75.6 ± 2.2 Kg in sports junior males and 52 ± 9.1 Kg in young sedentary males. Step-wise multiple regression analysis of somatotype components on aerobic power revealed dominant negative contribution (P < 0.001) of endomorphy (r2 = 0.57, 57%), and small but significant positive contributions of mesomorphy (0.6%) and ectomorphy (0.6%): Aerobic power = [56.1 - 4.3 (endomorphy) + (mesomorphy) + 1.4 (ectomorphy)] ± 9.1 SEE. Height and somatotype components accounted for 69% of the variance (R2) in grip strength;height had greatest contribution (60%): Grip Strength = [1.7 (Height) - 6.5 (ectomorphy) - 3.4 (endomorphy) - 2 (mesomorphy) - 200] ± 12.9 SEE. Measured variables accounted for <2% of flexibility variance. Conclusion: Endomorphy contributes greatly and negatively to variance in aerobic power. Body height was the anthropometric variable with the greatest positive association with the variance in grip strength. Flexibility appears to be unrelated to somatotype components.

Effects of Trekking Pole Use on Metabolic Cost in Novice Hikers on Steep Terrains

PURPOSE： This study examined whether the use of trekking poles alters metabolic cost in steep hiking by novice hikers and whether the response would be dependent on the grade of the terrain. METHODS： Twelve participants completed two trekking trials （with poles [WP] and without trekking poles [NP]） with round trips comprising three grades： 7.0 ± 0.7°, 12.9 ± 0.7°, and 18.8 ± 1.3°） over a steep mountain at self-paced speeds. During the trials, time spent for trekking （TT）, oxygen consumption （VO2）, heart rate （HR）, ratings of perceived exertion （RPE）, and step frequency （Sf） were measured, and step efficiency （Se） and oxygen pulse （OP） were calculated. RESULTS： TT tended to be longer in the WP than NP for both terrains （P 〈 0.05）. HR, VO2, and RPE were the same for the WP and NP. Sfwas lower in WP going uphill （P 〈 0.05） but was unchanged going downhill. Se in the WP was higher than in the NP for both terrains （P 〈 0.01）. When analyzed by slope, VO2 during uphill at 18.8° was lower in WP （37.2 ± 6.3） than in NP （38.6 ± 7.1 ml .kg-1 .min-1, P 〈 0.05）, but no difference in VO2 was found between WP and NP at the 12.9° and 7.0°. TT during uphill was slower in WP than NP at 12.9°（7.9± 1.1 vs. 7.4 ± 1.0） and 18.8° （5.3 ± 1.3 vs. 4.9± 1.0 min, respectively, P 〈 0.05）. No differences were noticed in HR and OP during uphill at every grade. CONCLUSIONS： Pole use decreased metabolic cost in the novice hikers only in the highest grade but not in the other two lower grades.

Perceived Improvements of Quality of Life (QoL) among Patients with Idiopathic Pulmonary Fibrosis (IPF) in Response to a 6-Week Rehabilitation Program

Idiopathic pulmonary fibrosis (IPF) is a chronic, life-limiting with an average life expectancy of 05 years following the onset of the disease, with no curative treatments. These patients need palliative care and rehabilitation is one of the methods that can be used to improve quality of life (QoL) among these patients. Yet the research conducted to assess benefits of pulmonary rehabilitation (PR) in terms of improving physical activity and QoL in IPF patients remains limited. Hence this study aims to evaluate the effect of a bespoke pulmonary rehabilitation programme, on the physical, physiological and psychological parameters and improvements of QoL among IPF patients. Eleven (11) subjects with IPF received 6 weeks of pulmonary rehabilitation. An interviewer administered quality of life questionnaire, six-minute walking test (6MWT), Incremental bicycle exercise tests were performed, and cardiac and respiratory parameters were assessed pre- and post-rehabilitation. The 6MWT was significantly increased following training (Pre 312.55 ± 89.99;Post, 380.73 ± 59.60). A significant improvement was observed in overall QoL (2.226 ± 0.026), dyspnoea (-0.455 ± 0.004) anxiety (-2.070 ± 0.038), depression (-2.217 ± 0.027) scores. No significant changes were found in the VO2 max and other cardiopulmonary parameters, while non-significant improvement was seen in SpO2 at peak exercise from 85.8 - 86.5. Bespoke pulmonary rehabilitation program is beneficial in short term improvement of the functional exercise capacity, dyspnoea and QoL among IPF patients.

Application of Six-minute Walk Test in Heart Transplantation Patients

Objectives To analyze the six-minute walk test （6MWT） and gas exchange of 5 heart transplantation patients and to approach the variation tendency of exercise tolerance, oxygen uptake （ VO2 ） and heart rate chronotropic response. Methods 5 cases of heart transplantation patients （ age 25 - 52 years） were undertaken 6MWT 6 - 30 months after operation, synchronizing gas exchanging parameters were measured by wireless portable remote sensing K4B^2 gas analyzer, 51 normal controls were compared. Results The six-minute walk distance （6MWD） of 5 patients were （592.6 ± 26.7 ） m （558 - 625 ） m, the ascending tendency during exercise was slower, the maximum heart rates were 80% ± 6% of age-predicting maximal heart rate, lower than normal control （86%） ; the end point VO2/kg were （21.8 ± 1.4 ） mL/min · kg （ 19. 94 - 23.60） mL/min · kg. Conclusions The 6WMD and VO2 of 5 patients reached normal range, but the heart rate chronotropic response and VO2 ascending tendency were slower than those of normal controls.

Dead Space Breathing in Patients with Malignancies: Determination by Cardiopulmonary Exercise Testing

Rationale: Patients with cancer commonly experience dyspnea originating from ventilatory, circulatory and musculoskeletal sources, and dyspnea is best determined by cardiopulmonary exercise testing (CPET). Objectives: In this retrospective pilot study, we evaluated patients with hematologic and solid malignancies by CPET to determine the primary source of their dyspnea. Methods: Subjects were exercised on a cycle ergometer with increasing workloads. Minute ventilation, heart rate, breathing reserve, oxygen uptake (V’O2), O2-pulse, ventilatory equivalents for carbon dioxide and oxygen (V’E/V’CO2 and V’E/V’O2, respectively) were measured at baseline and peak exercise. The slope and intercept for V’E/V’CO2 was computed for all subjects. Peak V’O2 4% predicted indicated a circulatory or ventilatory limitation. Results: Complete clinical and physiological data were available for 36 patients (M/F 20/16);32 (89%) exhibited ventilatory or circulatory limitation as shown by a reduced peak V’O2 and 10 subjects with normal physiologic data. The largest cohort comprised the pulmonary vascular group (n = 18) whose mean ± SD peak V’O2 was 61% ± 17% predicted. There were close associations between V’O2 and spirometric values. Peak V’E/V’O2 and V’E/V’CO2 were highest in the circulatory and ventilatory cohorts, consistent with increase in dead space breathing. The intercept of the V’E-V’CO2 relationship was lowest in patients with cardiovascular impairment. Conclusion: Dyspneic patients with malignancies exhibit dead space breathing, many exhibiting a circulatory source for exercise limitation with a prominent pulmonary vascular component. Potential factors include effects of chemo- and radiation therapy on cardiac function and pulmonary vascular endothelium.

Physiological and perceptual responses to sprint interval exercise using arm versus leg cycling ergometry

Increases in power output and maximal oxygen consumption(V_O2max)occur in response to sprint interval exercise(SIE),but common use of“all-out”intensities presents a barrier for many adults.Furthermore,lower-body SIE is not feasible for all adults.We compared physiological and perceptual responses to supramaximal,but“nonall-out”SIE between leg and arm cycling exercise.Twenty-four active adults(mean±SD age:[25±7]y;cycling VO_(2)max:[39±7]mL·kg^(-1)·min^(-1))performed incremental exercise using leg(LCE)and arm cycle ergometry(ACE)to determine VO_(2)max and maximal work capacity(Wmax).Subsequently,they performed four 20 s bouts of SIE at 130% Wmax on the LCE or ACE at cadence=120-130 rev/min,with 2 min recovery between intervals.Gas exchange data,heart rate(HR),blood lactate concentration(BLa),rating of perceived exertion(RPE),and affective valence were acquired.Data showed significantly lower(p<0.001)absolute mean([1.24±0.31]L·min^(-1) vs.[1.59±0.34]L·min^(-1);d=1.08)and peak VO_(2)([1.79±0.48]L·min^(-1) vs.[2.10±0.44]L·min^(-1);d=0.70)with ACE versus LCE.However,ACE elicited significantly higher(p<0.001)relative mean([62%±9%]VO_(2)max vs.[57%±7%]VO_(2)max,d=0.63)and peak VO_(2)([88%±10%]VO_(2)max vs.[75%±10%]VO_(2)max,d?1.33).Post-exercise BLa was significantly higher([7.0±1.7]mM vs.[5.7±1.5]mM,p=0.024,d?0.83)for LCE versus ACE.There was no significant effect of modality on RPE or affective valence(p>0.42),and lowest affective valence recorded(2.0±1.8)was considered“good to fairly good”.Data show that non“all-out”ACE elicits lower absolute but higher relative HR and VO_(2) compared to LCE.Less aversive perceptual responses could make this non-all-out modality feasible for inactive adults.

Aeration optimization through operation at low dissolved oxygen concentrations:Evaluation of oxygen mass transfer dynamics in different activated sludge systems

In wastewater treatment plants（WWTPs）using the activated sludge process,two methods are widely used to improve aeration efficiency — use of high-efficiency aeration devices and optimizing the aeration control strategy. Aeration efficiency is closely linked to sludge characteristics（such as concentrations of mixed liquor suspended solids（MLSS）and microbial communities）and operating conditions（such as air flow rate and operational dissolved oxygen（DO）concentrations）. Moreover,operational DO is closely linked to effluent quality. This study,which is in reference to WWTP discharge class A Chinese standard effluent criteria,determined the growth kinetics parameters of nitrifiers at different DO levels in small-scale tests. Results showed that the activated sludge system could meet effluent criteria when DO was as low as 0.3 mg/L,and that nitrifier communities cultivated under low DO conditions had higher oxygen affinity than those cultivated under high DO conditions,as indicated by the oxygen half-saturation constant and nitrification ability. Based on nitrifier growth kinetics and on the oxygen mass transfer dynamic model（determined using different air flow rate（Q′air）and mixed liquor volatile suspended solids（MLVSS）values）,theoretical analysis indicated limited potential for energy saving by improving aeration diffuser performance when the activated sludge system had low oxygen consumption; however,operating at low DO and low MLVSS could significantly reduce energy consumption. Finally,a control strategy coupling sludge retention time and MLVSS to minimize the DO level was discussed,which is critical to appropriate setting of the oxygen point and to the operation of low DO treatment technology.

Dietary Supplement with a Combination of Rhodiola Crenulata and Ginkgo Biloba Enhances the Endurance Performance in Healthy Volunteers

Objective:To determine whether the ingestion of a herbal supplement called Rhodiola-Gingko Capsule(RGC) would enhance the endurance performance of healthy volunteers and change relevant hormones in a favorable manner.Methods:Seventy healthy male volunteers(age ranges from 18 to 22 years old) were randomly assigned to RGC group(35 cases,each capsule containing 270 mg herbal extracts,4 capsules per day) or placebo group(35 cases,equivalent placebo preparation) for 7 weeks using computerproduced digital random...