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Physiological responses to maximal effort wheelchair and arm crank ergometry.

The purpose of this investigation was to compare physical work capacity (PWC), peak oxygen uptake (peak VO2), maximal pulmonary ventilation (VEmax), maximal heart rate (HRmax), and maximal blood lactate concentration (LAmax) for wheelchair ergometer (WERG) and arm crank ergometer (ACE) exercise. For this, wheelchair-dependent (n = 6) and able-bodied (n = 10) subjects completed a progressive intensity, discontinuous test for each mode of exercise. Each test was terminated by physical exhaustion and/or an inability to maintain a flywheel velocity of 180 m.min-1. Relatively high correlation coefficients were found between values obtained during the two modes of ergometry for PWC, peak VO2, VEmax, and HRmax. WERG exercise was found to elicit a significantly (P less than 0.05) lower PWC (by 36%), HRmax (by 7%), and LAmax (by 26%) than ACE exercise. Peak VO2 and VEmax, however, were similar for both exercise modes. These data suggest that either exercise mode may be used for fitness testing and training of people who cannot use their legs and that arm cranking may be a superior method to propel wheelchairs.

Adult↗

Exercise efficiency during arm ergometry: effects of speed and work rate.

The purpose of this investigation was to determine the effects of increasing work rate and speed of movement on efficiency during steady-state arm crank ergometry (ACE). Ten men exercised at speeds of 50, 70, and 90 rpm and four power outputs (15, 30, 45, and 60 W). O2 uptake determinations were made using open-circuit spirometry and energy expenditure was calculated from the respiratory exchange ratio. Gross (work accomplished/energy expended), work (unloaded cranking as base-line correction), and delta (measurable work as base-line correction) efficiencies were computed. A curvilinear relationship was found to exist between work rate and energy expenditure, which dictates that both delta and work efficiency will decrease with increments in work. Work (range 20-29%) and delta (range 14-30%) efficiencies decreased with increases in power output. The result that gross efficiency (range 6-15%) increased with increments in work was due to the decreasing effect of the resting metabolic rate on the total energy expended. Gross, work, and delta efficiencies were lower (P less than 0.05) at 90 rpm when compared with the same work rate at 50 and 70 rpm. Although all of the exercise efficiencies tended to be lower at 70 rpm compared with work at 50 rpm, the difference was significant (P less than 0.05) only at 45 and 60 W. These data suggest that delta and work efficiencies during ACE are decreased with increments in either speed or power output. However, gross efficiency increases as a function of power output but decreases as a function of speed of movement.

Adult↗

Relationship between body and leg VO2 during maximal cycle ergometry.

It is not known whether the asymptotic behavior of whole body O2 consumption (VO2) at maximal work rates (WR) is explained by similar behavior of VO2 in the exercising legs. To resolve this question, simultaneous measurements of body and leg VO2 were made at submaximal and maximal levels of effort breathing normoxic and hypoxic gases in seven trained male cyclists (maximal VO2, 64.7 +/- 2.7 ml O2.min-1.kg-1), each of whom demonstrated a reproducible VO2-WR asymptote during fatiguing incremental cycle ergometry. Left leg blood flow was measured by constant-infusion thermodilution, and total leg VO2 was calculated as the product of twice leg flow and radial arterial-femoral venous O2 concentration difference. The VO2-WR relationships determined at submaximal WR's were extrapolated to maximal WR as a basis for assessing the body and leg VO2 responses. The differences between measured and extrapolated maximal VO2 were 235 +/- 45 (body) and 203 +/- 70 (leg) ml O2/min (not significantly different). Plateauing of leg VO2 was associated with, and explained by, plateauing of both leg blood flow and O2 extraction and hence of leg VO2. We conclude that the asymptotic behavior of whole body VO2 at maximal WRs is a direct reflection of the VO2 profile at the exercising legs.

Adult↗

Assessment of brachial artery blood flow across the cardiac cycle: retrograde flows during cycle ergometry.

We describe a novel software system that utilizes automated algorithms to perform edge detection and wall tracking of high-resolution B-mode arterial ultrasound images, combined with synchronized Doppler waveform envelope analysis, to calculate conduit arterial blood flow (BF) across the cardiac cycle. Furthermore, we describe changes in brachial arterial BF to the resting forearm during incremental cycle ergometry in eight subjects. During exercise, peak BF during the cardiac cycle increased at each workload (P < 0.001), because of increased velocity in the presence of unaltered cross-sectional area. In contrast, mean BF calculated across each cardiac cycle decreased at lower workloads before increasing at 100 and 160 W (P < 0.001). Differences in the pattern of peak and mean cardiac cycle flows were due to the influence of retrograde diastolic flow, which had a larger impact on mean flows at lower workloads. In conclusion, BF can be measured with high temporal resolution across the cardiac cycle in humans. Resting brachial arterial flow, including retrograde flow, increases during lower limb exercise.

Adult↗

Leg blood flow during submaximal cycle ergometry is not reduced in healthy older normally active men.

The purpose of the present study was to test the hypothesis that leg blood flow responses during submaximal cycle ergometry are reduced with age in healthy normally active men. Eleven younger (20-25 yr) and eight older (62-73 yr) normotensive, nonendurance-trained men performed both graded and constant-load bouts of leg cycling at the same absolute and relative [% of peak O(2) consumption (Vo(2 peak))] exercise intensities while leg blood flow (femoral vein thermodilution), mean arterial pressure (MAP; radial artery), cardiac output (acetylene rebreathing), blood O(2) content, and plasma catecholamines were measured. Leg blood flow responses at the same absolute submaximal power outputs (20-100 W) and at a fixed systemic O(2) demand (1.1 l/min) did not differ between groups (P = 0.14-0.19), despite lower absolute levels of cardiac output in the older men (P < 0.05). MAP at the same absolute power outputs was 8-12 mmHg higher (P < 0.05) in the older men, but calculated leg vascular conductance responses (leg blood flow/MAP) were identical in the two groups (P > 0.9). At the same relative intensity (60% Vo(2 peak)), leg norepinephrine spillover rates were approximately twofold higher in the older men (P = 0.38). Exercise-induced increases in leg arterial-venous O(2) difference were identical between groups (P > 0.9) because both arterial and venous O(2) contents were lower in the older vs. younger men. These results suggest that the ability to augment active limb blood flow and O(2) extraction during submaximal large muscle mass exercise is not impaired but is well preserved with age in healthy men who are normally active.

Absorptiometry, Photon↗

Ergometry in the assessment of arterial hypertension.

The blood pressure behavior during and after ergometric exercise was investigated in 552 males in order to clarify if this standardized procedure is suitable for differentiating between normotensive subjects and hypertensive patients. Patients suffering from mild hypertension showed significantly (p less than 0.001) higher blood pressures (213 +/- 22/116 +/- 11 mm Hg) at 100 W and after loading than age-matched normotensives (188 +/- 14/92 +/- 9 mm Hg) but significantly (p less than 0.001) lower values than hypertensives with stable hypertension (225 +/- 22/126 +/- 11 mm Hg). Moreover, the systolic pressure response to ergometric work was significantly (p less than 0.05--p less than 0.01) influenced by age. Using the normal upper limits for blood pressure during and after ergometry the ergometric procedure revealed that 50% of the patients with borderline hypertension at rest could be classified as hypertensives. Their blood pressure response at 100 W (216 +/- 21/113 +/- 8 mm Hg) did not significantly differ from the patients with mild hypertension. In contrast, in the 50% who reacted negatively to ergometric testing, the systolic blood pressure response at 100 W (204 +/- 18 mm Hg) was significantly (p less than 0.01) lower than that of those who demonstrated a positive reaction, revealing exactly the same diastolic blood pressure value of 92 mm Hg as the normotensives. The present study strongly suggests that the assessment of blood pressure during ergometric testing is quite useful in distinguishing between normotensive and hypertensive patients and in making estimates of blood pressure response to daily stress more accurate.

Aged↗

A polygraphic study of systolic time intervals and their correlations with heart rate and workload during supine ergometry in one hundred normal subjects.

The present study was designed to investigate systolic time intervals (STI) in 100 normal subjects undergoing continuous-maximal supine cycle ergometry and to search for possible linear correlations between STI (dependent variables) and heart rate, diastolic blood pressure, systolic blood pressure, age, sex, weight, and height (independent variables), by stepwise regression analysis. The only significant correlation discovered in the study was between the contractility index (isometric contraction time-ICT) and the total work produced by each participant. Exercise tolerance was limited primarily by shortening of the ICT interval, all subjects discontinuing the test when ICT reached 13.7 +/- 7 ms.

Adult↗

Functional translation of exercise responses during combined arm-leg ergometry.

Previous studies have shown that the absolute power output required to produce a desired training heart rate could be predicted from the power output-heart rate relationship during exercise testing. The intent of this study was to develop an equation for the functional translation of exercise responses using combined arm-leg ergometry. Volunteer subjects (n = 16) performed exercise testing and three, 20-min exercise training sessions at different intensities on the combined arm-leg ergometer. Power output during exercise testing and training were well related (r = 0.905) with a small standard error estimate (12.1 W). Cross-validation of the regression equation developed from the validation sample yielded a high correlation (r = 0.969) with no differences between predicted and observed training heart rates.

Adult↗

Symptoms, lactate and exercise limitation at peak cycle ergometry in adults with cystic fibrosis.

The purpose of this study was to investigate symptoms, lactate accumulation and limiting factors at peak exercise in cystic fibrosis (CF) patients. In total, 104 CF adults attending an adult CF centre and 27 controls performed progressive cycle ergometry to a symptom-limited maximum. Measurements taken at peak exercise included: heart rate, ventilation, oxygen uptake, carbon dioxide output, oxygen saturation and blood lactate. Symptom scores of perceived breathlessness and muscle effort were recorded using Borg scales. The CF subjects had a lower mean body mass index, forced expiratory volume in one second (FEV(1)) and peak oxygen uptake than controls. Peak lactate concentrations were very similar to controls (mean+/-sd 6.8+/-2.0 mmol x L(-1) versus 7.4+/-1.0 mmol x L(-1)). Symptom scores were no different to controls for either breathlessness (4.5+/-2.0 versus 4.3+/-1.0) or perceived muscle effort (6.1+/-2.0 versus 6.5+/-1.0), with higher scores for muscle effort than breathlessness in both groups. In addition, peak ventilation was lower than the predicted maximum, and high peak heart rates were recorded supporting nonpulmonary factors as important in limiting peak exercise. Peak oxygen uptake was correlated with FEV(1). Comparison of CF subjects with mild or moderate pulmonary disease and controls revealed similar exercise responses. In contrast, those CF patients with severe lung disease (FEV(1) <40% predicted) had significantly higher breathlessness, lower muscle effort scores, lower peak lactate, lower peak heart rate and a mean ventilation exceeding predicted, thus confirming that ventilation was the major factor limiting exercise. In conclusion, cystic fibrosis subjects have a reduced peak exercise capacity, but their exercise response is similar to controls in generating high blood-lactate concentrations and symptoms of muscle effort in excess of dyspnoea. Nonpulmonary factors influence peak performance more in those without severe disease.

Adult↗

A comparison of incremental exercise tests during cycle and treadmill ergometry.

We evaluated a short-duration maximum exercise test by comparing a 15-s incremental exercise protocol with a 1-min incremental method. Twenty normal men and women were studied using cycle and/or treadmill ergometry. In subjects tested on both exercise devices, anaerobic threshold and maximal oxygen uptake (VO2max) were higher for both protocols on the treadmill than on the cycle ergometer (P less than 0.001). However, when the 15-s and 1-min tests were compared using the same device (treadmill or cycle), there were no significant differences between protocols in anaerobic threshold or maximum exercise values of minute ventilation, respiratory rate, tidal volume, VO2max, oxygen pulse, and peak expiratory flow rate. Linear regression analyses indicated differences between the 15-s and 1-min protocols when cardiopulmonary measurements were related to power; however, the two protocols were comparable when cardiopulmonary data were related to oxygen uptake. Comparisons between protocols or between exercise devices were not systematically different in large vs small individuals, or in men vs women. Short-duration incremental exercise tests appear to be reliable, practical methods for assessing exercise performance in normal individuals.

Exercise Test↗

Accurate prediction of VO2max in cycle ergometry.

Numerous equations exist for predicting VO2max from the duration (an analog of maximal work rate, Wmax) of a treadmill graded exercise test (GXT). Since a similar equation for cycle ergometry (CE) was not available, we saw the need to develop such an equation, hypothesizing that CE VO2max could be accurately predicted due to its more direct relationship with W. Thus, healthy, sedentary males (N = 115) and females (N = 116), aged 20-70 yr, were given a 15 W.min-1 CE GXT. The following multiple linear regression equations which predict VO2max (ml.min-1) from the independent variables of Wmax (W), body weight (kg), and age (yr) were derived from our subjects: Males: Y = 10.51 (W) + 6.35 (kg) - 10.49 (yr) + 519.3 ml.min-1; R = 0.939, SEE = 212 ml.min-1. Females: Y = 9.39 (W) + 7.7 (kg) - 5.88 (yr) + 136.7 ml.min-1; R = 0.932, SEE = 147 ml.min-1 Using the 95% confidence limits as examples of worst case errors, our equations predict VO2max to within 10% of its true value. Internal (double cross-validation) and external cross-validation analyses yielded r values ranging between 0.920 and 0.950 for the male and female regression equations. These results indicate that use of the equations generated in this study for a 15 W.min-1 CE GXT provides accurate estimates of VO2max.

Adult↗

Cardiovascular physiology during supine cycle ergometry and dobutamine stress.

PURPOSE: This study compared cardiac hemodynamics during supine cycle ergometry and dobutamine stress. METHODS: Thirty-two healthy volunteers (19 female, 13 male, 23.5 +/- 3.5 yr old) completed respective tests on separate days and in random order. Heart rate, blood pressure, and cardiac output were recorded at baseline and peak stress. Echocardiographic measures included left ventricular end-diastolic dimension, fractional shortening, heart rate corrected velocity of circumferential fiber shortening, end-systolic wall stress, and the difference between measured and predicted fiber shortening for measured wall stress. RESULTS: Compared with peak exercise, dobutamine infusion resulted in lower cardiac output (12 +/- 2 vs 16 +/- 4 l x min(-1), P < 0.0001), heart rates (163 +/- 7 vs 175 +/- 12 beats x min(-1), P < 0.0001), and systolic blood pressure (160 +/- 22 vs 185 +/- 20 mm Hg, P < or = 0.0001). Echocardiography demonstrated smaller left ventricular end-diastolic dimension (4.2 +/- 0.7 vs 4.5 +/- 0.7 cm, P = 0.013), higher fractional shortening (0.55 +/- 0.07 vs 0.50 +/- 0.06%, P < 0.001), higher VCFc (2.07 +/- 0.36 vs 1.54 +/- 0.20 circs x s(-1), P < 0.001) higher VCFdiff (0.94 +/- 0.35 vs 0.48 +/- 0.20 circs x s(-1), P < 0.001), and lower end-systolic wall stress (25 +/- 11 vs 42 +/- 16 g x cm(-2), P < 0.001). The stress-velocity relationship during dobutamine demonstrated higher y-intercept and steeper slope, indicating greater load-independent contractility. CONCLUSION: The cardiovascular adaptation to exercise and dobutamine stress differ significantly. Cardiac output during peak exercise is greater than during peak dobutamine secondary to increased heart rate and stroke volume. Despite a greater increase in contractility and decrease in afterload, a smaller increase in cardiac output during dobutamine stress may be secondary to limited ventricular preload.

Adaptation, Physiological↗

Metabolic responses to arm ergometry and functional neuromuscular stimulation.

The hips and lower extremities of four complete paraplegic male subjects (T-6, T-7, T-8, and T-11) were stimulated with functional neuromuscular stimulation (FNS) via transcutaneous intramuscular electrodes (20 mA, 0-150 pulse width, and 20 Hz). Cardiopulmonary (CP) and/or cardiovascular (CV) responses were measured during maximal (seated) arm ergometry (AE), FNS, and FNS + AE. Subjects' lower extremities were stimulated with a 2 s walking cycle via a microprocessor computer. Data were collected with a SensorMedic MMC Horizon (VO2 and VCO2 at STPD and VE at BPTS). The mean MET level (1 MET = 3.5 ml O2/kg/min) during FNS was 4.8. Mean METS during FNS + AE was 10.3 and mean METS for AE was 7.2. Mean lactic acid (LA) after FNS, AE, and FNS + AE was 73 mg percent, 77 mg percent and 115 mg percent respectively. Respiratory exchange ratio (RER) (VCO2/VO2) was greater than 1.2 during the first 2 to 5 min of FNS but decreased to less than 1.0 during the second 5 min of FNS. Steady state VO2 and RER less than 1.0 indicated a FNS transition from anaerobic to aerobic metabolism. Subject T-11 had CV limitations during FNS and FNS + AE due to excessive LA from FNS (115 mg percent). Ventilatory (VE) responses during AE, FNS, and FNS + AE were consistent with VO2; and mean maximal VE and VO2 for subjects T-6, T-7, and T-8 during FNS + AE was greater than 90 percent of that observed in sedentary normals. The aerobic and anaerobic capacities of paraplegic subjects is primarily limited by available muscle mass rather than impaired CV or CP function.

Adult↗

Sex differences in naturally occurring leg muscle pain and exertion during maximal cycle ergometry.

This investigation examined the role of sex in perceptions of leg muscle pain during exercise. Males (N = 26; age = 23.2 +/- 3.9) and females (N = 26; age = 21.9 +/- 3.5) matched on weekly energy expenditure completed a ramped maximal cycle ergometry test. Leg muscle pain thresholds were determined and pain intensity ratings as well as ratings of perceived exertion were obtained during and after exercise. The power output at pain threshold was lower in females (129.9 +/- 46.5 watts) compared to males (148.2 +/- 56.6 watts). Peak power output and peak pain intensity ratings were lower (P < 0.001) in females (211.3 +/- 39.1 watts; 5.5 +/- 2.9) compared to males (303.6 +/- 27.5 watts; 8.5 +/- 2.3). A Sex X Relative Intensity (i.e., % peak power output) ANOVA revealed that females reported lower pain ratings at each relative intensity examined (F = 17.7; df = 1.50; p < 0.001). The primary conclusion of this investigation is that females rate naturally occurring leg muscle pain as less intense than males when data are relativized to peak power output.

Adult↗

Exercise electrocardiography using rowing ergometry suitable for leg amputees.

Patients unable to perform heavy leg exercises cannot perform standard exercise ECG tests using bicycle or treadmill ergometry. A rowing ergometer was developed to enable an electrocardiographic stress test. Sixteen ambulatory patients with documented coronary insufficiency performed graded exercises. Comparison revealed no significant differences in several areas. Eleven patients with above-knee amputations, inevitable because of peripheral vascular disease, were able to perform rowing exercise only. This can result in cardiac loads adequate for diagnosis of coronary heart disease. No patient experienced difficulties with rowing. Rowing exercise can be a suitable alternative to bicycle exercise for the evaluation of coronary artery disease.

Adult↗

Mechanomyographic responses to continuous, constant power output cycle ergometry.

PURPOSE: The purpose of the present investigation was to examine the mechanomyographic (MMG) and electromyographic (EMG) responses to continuous, constant power output cycle ergometer workbouts. METHODS: Eight adult male volunteers (mean age +/- SD = 22 +/- 2 yrs) performed three continuous, one-hour workbouts at 28, 35, and 42% of peak power (Ppeak). RESULTS: The slope coefficients for the mean normalized MMG amplitude versus time relationships were significantly (p < 0.05) less than zero, while the slope coefficients for the mean normalized EMG amplitude versus time relationships were significantly (p < 0.05) greater than zero. CONCLUSION: The results indicated dissociation between the patterns of the mechanical (MMG) and electrical (EMG) activity of the vastus lateralis during continuous cycle ergometry at low power outputs. The increases in EMG amplitude were likely due to the recruitment of additional motor units. The decreases in MMG amplitude across time may have been due to the phenomenon known as "muscular wisdom" and/or decreases in muscular compliance.

Adult↗

[A comparative evaluation of the importance of transesophageal electrical stimulation of the left atrium and of bicycle ergometry in the diagnosis of ischemic heart disease in patients with arterial hypertension].

To make a comparative assessment of transesophageal left atrial pacing (TLAP) and bicycle ergometry (BE) in the diagnosis of coronary heart disease (CHD) in patients with arterial hypertension (AH) of different origin, the authors examined 56 patients. The patients underwent TLAP and selective coronary angiography, of them 39 patients had BE testing. No significant differences were found in their specificity (73 and 78%) and sensitivity (92 and 81%) between TLAP and BE, respectively. The maximum heart rate in CHD patients with AH was significantly higher (130 +/- 6 per min) during TLAP than that in BE (112 +/- 5 per min, p > 0.05), ischemic changes occurring at the same value of double product despite the mode of myocardial ischemia induction in these functional tests (240 +/- 10 and 236 +/- 12 arbitrary units, respectively; p < 0.05). The mean systolic blood pressure was higher in TLAP and in BE (210 +/- 10 and 185 +/- 8 mm Hg). This follows that TLAP and BE finding are comparable and no profound changes occur in TLAP, hence it can be recommended for wide application in the diagnosis of CHD in AH patients.

Adult↗

[Bicycle ergometry in patients with unstable stenocardia: its performance potentials and diagnostic and prognostic significance].

As many as 175 patients with unstable angina pectoris were examined. After the patients' status was stabilized by drug therapy on days 3-31 (after 12.5 days on the average) bicycle ergometry was performed in accordance with a standard technique. In all the cases, the exercise test produced no complications. 134 patients underwent coronary angiography to define the long-term outcome. The patients with ECG changes seen during the test and those with angina pectoris attacks alone without any changes on the ECG manifested multiple vascular lesions significantly more often than those with negative exercise results. If there were changes in the ST segment during exercise, the complications (myocardial infarction, coronary death, unstable angina pectoris relapses) common to the long-term period which lasted 25.7 months on the average were recorded significantly more often (p less than 0.01) as compared to the patients with negative exercise results.

Adult↗