Maximal Work Performance Research Articles

A new method for data presentation in incremental cardiorespiratory exercise testing.

In incremental cardiopulmonary exercise testing, the averaging of data is usually performed to provide group mean data for statistical purposes. They are usually presented as averaged maximum values, or as averaged data at different exercise levels. However, during incremental exercise testing the change in metabolic status may vary between subjects, thus averaging data may not classify the metabolic status accurately. We present an averaging method using a segmented ordinal scale based on individual maximal work performance and the anaerobic threshold (AT). Individual exercise data are grouped into ten classes ranging from unloaded exercise to maximal exercise. The classes are defined in relation to the AT, resulting in an ordinal scale of four classes for exercise data below the AT, one class at the AT and five classes beyond the AT. Resting and unloaded pedalling are treated as separate classes. For evaluation, this method of classification is compared to one based on an absolute scale of oxygen uptake (Cabs) and to another based on a relative scale in 10% steps of maximal oxygen uptake (Crel). Ten healthy male subjects (mean age 23.3 years) performed a ramp cycle ergometer test. When using the Cabs classification method for mean data averaging, mean values for performance at high-intensity exercise were calculated using data from only two of the ten subjects because of variations in individual work capacity. In addition, the AT data were distributed across four classes, thus anaerobic and aerobic exercise data were mixed. Using the Crel classification method enabled data for all ten subjects to be included in the calculation of every data point, but the AT values were still distributed across three classes, resulting in the mixing of anaerobic and aerobic exercise data. However, using the segmented ordinal scale method of classification enabled data from all ten subjects to be included in the calculation of all data points, and it permitted the grouping of the AT values into one class. Thus, this latter method more accurately represents the data of the whole group under study and it allows the metabolic status of the subjects to be taken into consideration.

Esophageal Pressure Measurements in Cardiopulmonary Exercise Testing

We sought to determine the adaptability and effectiveness of a new esophageal balloon technique to measure changes in esophageal pressure (Pes) as a reflection of pleural pressure with progressive incremental exercise testing in normal subjects. An 8F (0.9 cm) esophageal balloon catheter (Smart Cath; Allied Health Products; Riverside, Calif), a CP-100 pulmonary monitor (BiCore Monitoring Systems PC-100; Irvine, Calif), and a flow transducer (Var flex; Allied Health Products; Riverside, Calif) were connected to a breathing valve (model 2700; Hans-Rudolph Inc; Kansas City, Mo). This apparatus was then used to measure Pes during a graded cardiopulmonary exercise test (CPX) to symptom limitation. University-affiliated Veterans Affairs Hospital. Eight nonsmoking volunteers with normal results of pulmonary function tests. Plots of deltaPes against pressure time product (PTP), minute ventilation (VE), and oxygen consumption (VO2) were obtained. Pes at baseline, anaerobic threshold (AT), and maximum oxygen consumption (VO2max) were obtained by comparing the Pes measurements from the computer printout to the corresponding breath-by-breath measurements on the CPX. The flow transducer (Varflex) connection added only 20 mL of dead space to the standard mouthpiece apparatus. The mean maximum work performance was 203+/-32 W. The mean VO2max was 29+/-9 mL/kg/min. The Pes at AT was 16+/-3 cm H2O. The Pes at maximal exercise was 42+/-16 cm H2O. The small esophageal balloon was well tolerated by all subjects. Plots of deltaPes vs PTP, VE, and VO2 demonstrated a linear correlation. This apparatus could be added to the standard CPX to assess the contribution of the diaphragm and respiratory muscles in patients with dyspnea.

Failure of chronic ginseng supplementation to affect work performance and energy metabolism in healthy adult females

Ginseng has long been used for various medicinal reasons in East Asia and has recently also become a popular nutritional supplement in Western countries. Although commonly alleged to increase work performance by enhancing the body resistance to stress and fatigue, human experimental research evidence to either support or refute these claims is limited and conflicting. Therefore, this randomized, double-blind, placebo-controlled study served to examine a group of healthy adult females who for eight weeks added 200 mg·day −1 of a concentrated extract of Panax Ginseng C.A. Meyer (n=10) or placebo (n=9) to their otherwise supplement-free normal diet. Before and after the trial intervention, each subject performed a graded maximal cycle ergometry test to exhaustion and completed a standard habitual physical activity questionnaire. It was observed that chronic ginseng supplementation had no effect on maximal work performance (J) and resting, exercise, and recovery oxygen uptake (V̇O 2, ml·kg −1·min −1), respiratory exchange ratio (RER), minute ventilation (V̇E, L·min −1), heart rate (beats·min −1), and blood lactic acid (mmol·L −1) levels (p>0.05). Habitual physical activity scores of study participants were found to be similar between the placebo and ginseng treatment groups and at the beginning and end of the eight week trial period (p>0.05). The present data in healthy adult females indicate that chronic dietary supplementation with a standardized extract of Panax Ginseng C.A. Meyer does not result in an enhancement of work performance or a change in energy metabolism and improvement of the recovery response from maximal physical work.

Maximal physical work performance with European standard based fire-protective clothing system and equipment in relation to individual characteristics.

Every fire fighter needs to wear fire-protective clothing and a self-contained breathing apparatus (SCBA) several times a year while carrying out various fire-fighting and rescue operations in hazardous work environments. The aim of the present study was to quantify the effects of a multilayer turnout suit designed to fulfil European standard EN 469 used over standardized (Nordic) clothing and with SCBA (total mass 25.9 kg) on maximal physical work performance, and to evaluate the relationship between individual characteristics and power output with the fire-protective clothing system and SCBA. The subjects were 12 healthy firemen aged 26-46 years. The range of their body mass, body fat and maximal oxygen consumption was 69-101 kg, 10-20% and 2.70-5.86 l.min-1, respectively. The maximal tests without (control) and with the fire-protective clothing system and SCBA were carried out on a treadmill in a thermoneutral environment. When compared to the control test, the decrease in the maximal power output in terms of maximal working time and walking speed averaged 25% (P < 0.001) varying from 18% to 34% with the fire-protective clothing system and SCBA. At maximum, no significant differences were found in pulmonary ventilation, absolute oxygen consumption, the respiratory exchange ratio, heart rate, systolic blood pressure, the rate-pressure product, mechanical efficiency, and the rating of perceived exertion between the tests with and without the fire-protective clothing system and SCBA. The reduction of the power output was related to the extra mass of the fire protective clothing and SCBA.(ABSTRACT TRUNCATED AT 250 WORDS)

Decline in maximal oxygen uptake on work performance in rats during the developmental phase.

Development-related changes in maximal oxygen uptake (VO2max) and work performance were examined in young sedentary rats 4-11 weeks after birth during exercise. The running speed to elicit VO2max increased from 4 to 8 weeks of age, whereas the exercise VO2max declined progressively. Therefore, the work performance during the developmental phase, when rapid growth occurs, seems to be little related to the decline in the relative VO2 max.

Chemomechanics of altered perfusion pressure in rat hearts.

In an apex-ejecting isolated perfused working rat heart, as well as isovolumic preparations of rat hearts, perfusion pressure was studied independent of afterload. A decrease in perfusion pressure caused an immediate decrease in developed pressure (10s). There was a significant increase in free Pi and the phosphorylation potential after 20-30 min of perfusion at a reduced coronary flow induced by a reduction in perfusion pressure. Developed pressure decreased prior to the phosphorylation potential and inorganic phosphate; however, the phosphorylation set a limit to maximum work performance. At a perfusion pressure of 140 cm H2O and an afterload of 140 cm H2O, work imposed on the heart was maximum; there was no further increase in work.

Behavioral Alterations in Iron Deficiency

This review has examined recent evidence from human studies that iron deficiency adversely affects behavior by impairing cognitive function, producing noncognitive disturbances, and limiting activity and work capacity. The body of research taken as a whole provides increasingly persuasive arguments for intensifying efforts to prevent and treat iron deficiency anemia. Cognitive Function. There is reasonably good evidence that mental and motor developmental test scores are lowered among infants with iron deficiency anemia. Although the research on cognitive function in iron-deficient older children and adults is sparse and diverse, it suggests that there may be alterations in attentional processes associated with iron deficiency. Iron therapy has not yet been shown effective in completely correcting the observed disturbances. Although some aspects of cognitive function seem to change with iron therapy, lower developmental, IQ, and achievement test scores have still been noted after treatment. Noncognitive Disturbances. A variety of noncognitive alterations during infant developmental testing has also been observed, including failure to respond to test stimuli, short attention span, unhappiness, increased fearfulness, withdrawal from the examiner, and increased body tension. Exploratory analyses suggest that such behavioral abnormalities may account for poor developmental test performance in infants with iron deficiency anemia. These studies indicate the fruitfulness of examining noncognitive aspects of behavior, such as affect and activity, in addition to specific cognitive processes. Activity and Work Capacity. There has been a steady accumulation of evidence that iron deficiency anemia limits maximal physical performance, submaximal endurance, and spontaneous activity in the adult, resulting in diminished work productivity with attendant economic losses. The mechanisms underlying these effects, the extent to which anemia or iron deficiency separate from anemia is responsible, and the counterpart in infants and children remain to be established.

High-altitude adaptation and maximum work performance.

The treadmill work performance of rats at sea level with normal or elevated hematocrits was compared with that of rats conditioned in a hypobaric chamber at 450 Torr for 3 wk with similar hematocrit adjustments. A mean increase in hematocrit to 62 significantly improved the work performance of rats at sea level and at ambient O2 tensions of 100, 75, and 35 Torr. By contrast, rats conditioned in a hypobaric chamber with mean hematocrits of 40 and 58 performed similarly at all O2 tensions compared with sea-level rats with hematocrits of 43. Thus, although an increase in O2-carrying capacity of the blood of sea-level animals increased work capacity, altitude adaptation did not appear to result in any positive effect on work capacity, and indeed, seemed to interfere with the beneficial effect of polycythemia on maximum work performance.

Platelet function related to the development and presenting symptoms in coronary artery disease. An epidemiological study in apparently healthy men.

Among 2014 apparently healthy men aged 40-59 years platelet function was studied with Hellem's retention method in 488 men. In 55 of these 488 men coronary heart disease (CHD) was strongly suspected and coronary angiography confirmed the diagnosis in 34 of 51 angiographied men. Platelet responsiveness was significantly lower among those who had angina pectoris than among their CHD-suspect counterparts without angina, regardless of coronary angiographic findings. Since angiopositive men without angina and 408 "normals" had similar retention values, it seems as if presenting symptoms, but not the development of CHD are linked to platelet function. During a near maximal bicycle exercise test significantly higher peak exercise blood pressure was found among men with very low retention values than among men with retention values in the middle and upper range. This could not be explained by differences in maximal heart rate or work performance. This indicates that blood pressure regulation during exercise may in part be linked to platelet function related mechanisms.

Prognosis of Women with Exercise-Induced ECG Changes &amp;ndash; Results from a Longitudinal Population Study

A comprehensive population study of women aged 38-60 was carried out in Göteborg, Sweden in 1968-1969. A subsample comprising 194 women were submitted to a maximal work performance test using a bicycle ergometer. Exercise-induced ECG changes were common and as common in women as in men in Göteborg who had been studied in the same way. ST depressions (Minnesota Code items 4:1-2) were observed 4 min after maximal exercise in 30 women. All these women were still alive when a follow-up was made 6 years later, none had had myocardial infarction, and only 2 of them reported symptoms of angina pectoris. 1 woman later on had a fatal myocardial infarction as was found in a 12-year-follow-up study. It is concluded that exercise-induced ECG changes are of limited value for predicting myocardial infarction or death from ischaemic heart disease in women.

Maximal work performance test in middle-aged women: results from a population study.

Based on sampling from official census lists a sample of middle-aged women was obtained in five different age strata; 38, 46, 50, 54 and 60 years. Based on date of birth a sub-set was sampled for maximal exercise testing. The participation rate was 81% and 194 women underwent the test. In sixteen women the test was interrupted due to poor cooperation or clinical contra-indications against continued loading. 54% of the women considered the maximal load to be at least very straining according to a standardized scale for perceived exertion. The average maximal load decreased from 113 to 98 W with advancing age. In the highest age group only 16% exceeded 130 W compared to 43% in the youngest group. Maximum heart rate decreased with age but maximum respiratory frequency and perceived exertion did not. Systolic blood pressure 2 min after maximal work increased with age. Minnesota Code items 4:1-3 and 5:1-3 were demonstrated in 30% of the women, mainly in the older age strata. Other ECG-abnormalities were uncommon. Despite the widely differing incidence of myocardial infarction these ischaemic ECG-abnormalities were as common in women as in a comparative sample of men. This observation questions the traditional interpretation of the exercise induced ECG response in women.

Decrease of maximum work performance following ozone exposure.

A bicycle ergometer was used to measure maximum exercise oxygen consumption following 2 h of intermittent exercise in an environmental chamber ventilated with air (FA test) or filtered air plus 0.75 ppm ozone (PO test). Thirteen adult males performed both tests according to a random sequence. The maximum attained VO2 declined 10% (P less than 0.01), maximum attained work load was reduced by 10% (P less than 0.01), maximum ventilation decreased 16% (P less than 0.01), and maximum heart rate dropped 6% (P less than 0.05) in the PO test. At the highest common work load, heart rate and oxygen consumption were similar and ventilation was slightly higher (P less than 0.05); however, frequency of respiration increased 45% (P less than 0.01) and tidal voluem fell by 29% (P less than 0.01) following ozone exposure. During maximum exercise, the respiratory frequency was similar in both tests, but tidal volume was 21% lower (P less than 0.01) in PO experiments. Decreases in vital capacity and FEV1.0 as well as cough and chest discomfort were also noted following ozone exposure. We conclude that the reduction of maximum attained VO2 is a consequence of ventilatory limitation of maximum effort, probably related to respiratory discomfort.

The effects of hypothermia on submaximal and maximal work performance.

The effects of hypothermia on submaximal and maximal work performance.

Maximal work performance at raised air and helium-oxygen pressures.

AbstractTo study the influence of increased air pressure and gas density on maximal work performance, cardiorespiratory measurements were made on 8 subjects who performed maximal exercise until exhaustion on a cycle ergometer while breathing air at ambient pressures of 1.0 (control), 3.0, and 6.0 ATA, and a mixture of 79 % helium and 21 % oxygen (He‐O2) at 3.0 ATA (same density as air at 1.0 ATA). Exposure to air at 3.0 and 6.0 ATA caused no consistent changes in maximal oxygen uptake (Vo2max), peak blood lactate (LA), or endurance time, whereas pulmonary ventilation (VE) and carbon dioxide elimination (Vco2) decreased significantly with a consequent rise of end‐tidal PCo2 from 35 mm Hg at 1.0 ATA, to 56 mm Hg at 6.0 ATA. Maximal heart rate (HRmax) decreased from a mean control value of 192 beats‐min‐1to 183 beats‐min‐1at 6.0 ATA. With exposure to He‐O2 at 3.0 ATA, as compared to control, Vo2max and endurance time increased by 13 % and 14 %, respectively, whereas VE and HRmax decreased, Vco2 and LA remained unchanged, and end‐tidal Pco2 rose to 39 mm Hg. It is concluded that the beneficial effect that hyperoxia exerts on Vo2max and endurance time at normal gas density is offset when the gas density is high enough to cause ventilatory impairment with concomitant CO2 retention. The results also suggest that maximal work performance was more closely related to the LA concentration than to the Pco2 or pH levels existing in the working muscles at the point of exhaustion.

A graded treadmill test for rats: maximal work performance in normal and anemic animals.

A graded treadmill test for rats: maximal work performance in normal and anemic animals.

Maximal Oxygen Intake and Maximal Work Performance of Active College Women

Abstract Maximal oxygen intake and other associated physiological variables were measured during strenuous exercise on fairly active women subjects (N = 20, physical education majors). The method described by Taylor et al. (14) was used. Following assessment of maximal oxygen intake, all subjects underwent an all-out performance test at the work level which had elicited her maximal oxygen intake. Mean maximal oxygen intake was 41.32 mi/kg/min and mean maximal heart rate was 185.8 bpm. In the endurance performance test the mean run time for all subjects was 4:35.8 min. Correlation between maximal oxygen intake and performance time was calculated and found to be insignificant (r = .07); however, a highly significant correlation was obtained between maximal oxygen intake and physical work done during the performance test (r = .64).

The mechanism of the increased maximum work performance of small muscle groups resulting from "diverting work" with other muscle groups.

AbstractThe mechanism of increased work performance resulting from “diverting works” was examined. Muscle blood flow was measured in exercised and rested muscles by means of venous occlusion plethysmography and 133Xe clearance. Measurements of muscle blood flow, blood pressure and work performance following “diverting work” and other stimuli were compared with values obtained during control rest periods. Stimuli which caused a substantial rise in arterial blood pressure (“diverting work”, change in heart level, pain) caused increases in blood flow and work performance in exercised muscles. Non‐pressor or mild pressor stimuli (non‐strenuous “diverting work”, CO2 inhalation, apnea, cold) resulted in unchanged blood flow and work values in the exercised muscles. It is concluded that pressor stimuli produce increased muscle blood flow in maximally ischemic muscles due to release of muscle arteries from neurogenic and myogenic control. The increased muscle blood flow during periods employing pressor stimuli results in improved muscle restitution and hence increased work performances.

Physical fitness in old age. II. Anearobic capacity, anearobic work in graded exercise, recovery after maximum work performance in elderly individuals.

Physical fitness in old age. II. Anearobic capacity, anearobic work in graded exercise, recovery after maximum work performance in elderly individuals.

Cardiorespiratory changes in college women due to a season of competitive basketball.

ARTICLESCardiorespiratory changes in college women due to a season of competitive basketballW. E. Sinning, and M. J. AdrianW. E. Sinning, and M. J. AdrianPublished Online:01 Dec 1968https://doi.org/10.1152/jappl.1968.25.6.720MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByComparative analysis of physiologic responses to three different maximal graded exercise test protocols in healthy womenAmerican Heart Journal, Vol. 103, No. 3Physiological Effects of Similar Training Programs in Males and Females17 March 2013 | Research Quarterly. American Alliance for Health, Physical Education and Recreation, Vol. 48, No. 3Effect of High Resistance and Low Resistance Bicycle Ergometer Training in College Women on Cardiorespiratory Function and Body Composition17 March 2013 | Research Quarterly. American Alliance for Health, Physical Education and Recreation, Vol. 48, No. 2Physiological Characteristics of Female Athletes17 March 2013 | Research Quarterly. American Alliance for Health, Physical Education and Recreation, Vol. 45, No. 4Physiological and Hematological Changes among Basketball Players during Preseason17 March 2013 | Research Quarterly. American Alliance for Health, Physical Education and Recreation, Vol. 45, No. 3Body Composition, Cardiorespiratory Function, and Rule Changes in Women's Basketball17 March 2013 | Research Quarterly. American Association for Health, Physical Education and Recreation, Vol. 44, No. 3Maximal Oxygen Intake and Maximal Work Performance of Active College Women17 March 2013 | Research Quarterly. American Association for Health, Physical Education and Recreation, Vol. 44, No. 2Cardiovascular Characteristics of Selected Track Participants in the First Annual Dgws Track and Field Meet17 March 2013 | Research Quarterly. American Association for Health, Physical Education and Recreation, Vol. 42, No. 4Aerobic Capacity, Heart Rate and Estimated Energy Cost during Women's Competitive Basketball17 March 2013 | Research Quarterly. American Association for Health, Physical Education and Recreation, Vol. 42, No. 2 More from this issue > Volume 25Issue 6December 1968Pages 720-724 Copyright & PermissionsCopyright © 1968 the American Physiological Societyhttps://doi.org/10.1152/jappl.1968.25.6.720PubMed5727198History Published online 1 December 1968 Published in print 1 December 1968 Metrics

Relation of increase in muscle mass to performance of hypertrophied right ventricle in the dog.

Right ventricular hypertrophy was produced by chronic constriction (banding) of the pulmonary artery in the dog. Right ventricular muscle mass increased by 40% in 6 to 12 weeks after banding. Maximal work performance of this ventricle also increased; at 12 weeks the mean was 175% more than that of the normal right ventricle. It was concluded that, per unit of gross myocardial mass, the work performance of the hypertrophied right ventricle of the dog was no less than that of the normal right ventricle.