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1.
Oxygen consumption ( O2), heart rate, ventilation and central rating of perceived exertion (RPE) in repetitive lifting while executing squat and stoop techniques were investigated in ten male forestry workers. In all five mass/frequency combinations studied, O2 was significantly higher for the squat than for the stoop technique. No differences were found in RPE between the techniques. The O2 and RPE recordings were also related to those obtained during maximal repetitive lifting (same lifting technique) and maximal treadmill running. The O2 expressed as a percentage of that obtained during maximal repetitive lifting with the same lifting technique was defined as relative aerobic intensity (% O2max, lifting). The % O2max, lifting was not significantly different between the techniques except for the lowest mass lifted (1 kg). This study therefore would support the hypothesis that RPE is more closely related to % O2max, lifting than to absolute aerobic intensity. Related to maximal treadmill running, it was demonstrated for both lifting techniques that relative RPE (percentage of the RPE during maximal running) was more accurate than relative O2 (percentage of maximal O2 during maximal running) for determining the % O2max, lifting in repetitive lifting. The study showed that the higher O2 during squat. lifting compared to stoop lifting was caused by the O2 expended in lifting and lowering the body rather than the O2 expended lifting and lowering the external mass. It was concluded that the stoop technique was not superior to the squat technique in terms of central RPE. Based on % O2max, lifting, there may be a rationale for choosing the stoop technique during repetitive lifting with light masses, but not with heavy masses.  相似文献   

2.
Summary Physiological responses were measured in 7 women subjects who lifted boxes weighing 6.8, 15.9 or 22.7 kg from the floor to a height of 60 cm. After training and establishing the O2 max, the boxes were lifted for 1 h at 30, 50, and 60% O2 max. The changes in heart rate, O2, the integrated EMG during lifting and the loss of isometric hand-grip endurance after lifting were used to assess the development of fatigue. There was no evidence of fatigue at 30% O2 max but fatigue did exist in some conditions at 50% and in all conditions at 60% O2 max. It is suggested that fatigue is unlikely to occur while lifting boxes up to 15.9 kg weight at 35–40% O2 max, i.e., at rates of lifting varying from 5 to 7 times per min.  相似文献   

3.
Summary The purpose of this study was to determine oxygen uptake O2) at various water flow rates and maximal oxygen uptake ( O2max) during swimming in a hypobaric hypoxic environment. Seven trained swimmers swam in normal [N; 751 mmHg (100.1 kPa)] and hypobaric hypoxic [H; 601 mmHg (80.27 kPa)] environments in a chamber where atmospheric pressure could be regulated. Water flow rate started at 0.80 m · s–1 and was increased by 0.05 m· s–1 every 2 min up to 1.00 m · s–1 and then by 0.05 m · s–1 every minute until exhaustion. At submaximal water flow rates, carbon dioxide production ( CO2), pulmonary ventilation ( E) and tidal volume (V T) were significantly greater in H than in N. There were no significant differences in the response of submaximal O2, heart rate (f c) or respiratory frequency (f R) between N and H. Maximal E,f R,V T,f c blood lactate concentration and water flow rate were not significantly different between N and H. However, VO2max under H [3.65 (SD 0.11) l · min–1] was significantly lower by 12.0% (SD 3.4) % than that in N [4.15 (SD 0.18) l · min–1] . This decrease agrees well with previous investigations that have studied centrally limited exercise, such as running and cycling, under similar levels of hypoxia.  相似文献   

4.
Summary An indirect test of maximal aerobic power (IMAP) was evaluated in 31 healthy male subjects by comparing it with a direct treadmill measurement of maximal aerobic power ( O2 max), with the prediction of O2 max from heart rate during submaximal exercise on a cycle ergometer using åstrand's nomogram, with the British Army's Basic Fitness Test (BFT, a 2.4 km run performed in boots and trousers), and with a test of maximum anaerobic power. For the IMAP test, subjects pedalled on a cycle ergometer at 75 revs·min–1. The workload was 37.5 watts for the first minute, and was increased by 37.5 watts every minute until the subject could not continue. Time to exhaustion was recorded. Predicted O2 max and times for BFT and IMAP correlated significantly (p<0.001) with the direct O2 max: r=0.70, r=0.67 and r=0.79 respectively. The correlation between direct O2 max and the maximum anaerobic power test was significant (p<0.05) but lower, r=0.44. Although lactate levels after direct O2 max determination were significantly higher than those after the IMAP test, maximum heart rates were not significantly different. Submaximal O2 values measured during the IMAP test yielded a regression equation relating O2 max and pedalling time. When individual values for direct and predicted O2 max and times for BFT and IMAP were compared with equivalent standards, the percentages of subjects able to exceed the standard were 100, 65, 87, and 87 respectively. These data demonstrate that the IMAP test provides a valid estimate of O2 max and indicate that it may be a practical test for establishing that an individual meets a minimum standard.  相似文献   

5.
Summary Aerobic fitness and percent body fat were measured in a sample of 438 male Army recruits between the ages of 17 and 30 prior to the commencement of training. The sample came from all areas of England and Wales. Aerobic fitness, as represented by maximal oxygen uptake ( O2 max), was predicted from the Astrand submaximal bicycle heart rate test. Body fat was predicted from four skinfold measurements. Total group means ±SD were: age, 19.5±2.5 years; O2 max 41.7 ±8.3 ml/kg·min; and body fat, 14.5±4.8% of body weight. O2 max varied with age, athletic participation and aptitude score. No relationship was found with occupation of parent, prior civilian occupation or smoking severity. When adjusted for methodological differences, O2 max was slightly below similar Army entrants in Norway and the United States.  相似文献   

6.
Summary Fourteen Subjects (6 male, 8 female) participated in a training program upon a bicycle ergometer for 7 weeks. Group CT followed a continuous training regimen 4 days per week at 70% O2 max. Group IT trained by an interval method at 100% O2 max. The duration of each training session was assigned so that each subject would complete 10,000 kpm of work per session during the first week. Each subsequent week, the work load was increased 3000 kpm. Pretraining tests included O2 max, standard 7 min tests at 80% O2 and 90% O2, an endurance test at 90%, and an intense anaerobic work bout at 2400 kpm. Variables assessed were O2, HR, and blood lactic acid concentrations. The mean increase in O2 max was 5.1 ml/kg min (15%) for both groups with a corresponding increase in maximal lactate of 20 mg-%. The response to the post-training tests was nearly identical for both groups: submaximal heart rate at the same absolute work load declined 17 beats/min (CT) and 15 beats/min (IT), submaximal lactate levels declined significantly, endurance ride duration increased 26 min. Continuous and interval training at 70% and 100% O2 max respectively produce identical changes in heart rate response, blood lactic acid concentration and O2 max when the total work load is equated per training session.  相似文献   

7.
To investigate pulmonary gas exchange and ventilatory responses to brief intense intermittent exercise and to study the effects of physical fitness on thes responses, nine trained and nine untrained healthy male subjects aged 18–33 years performed the force-velocity (F-) exercise test. This test consisted of 6-s sprints against increasing braking forces (F) separated by 5-min recovery periods. Oxygen uptake ( ), carbon dioxide output ( CO2), and ventilation E) were continuously measured during the test and the magnitudes of their responses to the sprints were then calculated.For all subjects CO2 increased rapidly after beginning the sprints, and the peaks of the responses (F = 13.4;P < 0.001), end of recovery values (F = 6.5;P < 0.01), and O2 magnitudes of response (F = 12.4;P < 0.001) rose significantly with the repetition of the sprints. The O2 magnitudes of response correlated with the corresponding sprint power outputs (r = 0.55;P < 0.001) and with the sprint repetitions (r = 0.51,P < 0.001). The CO2 (F = 7.1;P < 0.01) and {ie442-8} (F = 5.0;P < 0.01) peaks of response increased with the initial load incrementation, then stabilized when the subjects attained peak power output. End of recovery CO2 (F = 18.0;P < 0.001) and E (F = 14.1;P < 0.001) values rose with increasingF. TheF- peak O2, CO2, E, tidal volume and respiratory frequency responses attained 53%, 40%, 44%, 66%, and 82% of the peak values measured at exhaustion of maximal graded exercise, respectively.Trained and untrained subjects had the same first sprint power output and braking, force. Nevertheless, the trained subjects had higher O2 peaks (F = 35.2;P < 0.001) and CO2 magnitudes of response (F = 30.0;P < 0.001) than the untrained subjects for all sprints. The higher peak O2 values represented similar percentages of maximal oxygen uptake in the trained and untrained subjects. In summary, the present study showed that in brief intense intermittent exercise, i.e. theF- test, the O2, CO2, and ventilatory responses in young subjects were submaximal with respect to the peak values attained at exhaustion of maximal graded exercise. The CO2 magnitude of response increase was related to the power output rise in the corresponding sprints and to the repetition of sprints. Moreover, the trained subjects presented higher CO2 peaks and magnitudes of response to the sprints than the untrained subjects.  相似文献   

8.
Summary The method described by Wasserman for anaerobic threshold (AT) determination, based on the recording of ventilatory parameters, was supported by the simultaneous appearance of hyperlactacidemia and hyperventilation during a standardized incremental work test. Our study aimed at testing the AT in another profile of exercise, viz., during exercises at constant workloads.A homogenous population of 66 healthy subjects performed on a treadmill a total of 100 exercises of 20 min duration at constant workloads (43, 48, 52, 57, 63, and 71% O2max). The O2, , and venous plasma lactic acid (LA) were determined every minute.LA showed an initial transient increase at 43% O2 max and a steady-state elevated level above 48% O2 max. In contrast, the hyperventilation threshold (HVT) was only observed above 57% O2 max, simultaneously with a delayed steady-state O2 and with a sustained increase of lactate until the end of exercise.The meaning of the simultaneity of these three events must still be studied. However, the dissociation between both early and steady-state lactate thresholds and HVT is not in keeping with the concept of AT. In these conditions, there is no evidence that HVT necessarily represents an AT, viz., a critical intensity of exercise inducing an insufficient oxygen delivery to the muscles. This conclusion does not imply that the measurement of HVT should be rejected as an empirical test of physical fitness.  相似文献   

9.
Summary The transmission of muscle oxygen uptake patterns to the pulmonary site is a basically nonlinear process during unsteady state exercise. We were mainly interested in three questions concerning the dynamic relationship between power input and pulmonary output: 1. To what extent can linear system analysis be applied? 2. What is the relative influence of muscle on pulmonary as compared to other parameters such as muscle perfusion kinetics? 3. To what extent does pulmonary reflect muscle ? Investigations were performed by means of a mathematical model including a muscle compartment and two serial, flow-varying time delays. The non-exercising parts of the body were. incorporated as one term for perfusion and one for . Parameters were adjusted so as to represent a reference state of aerobic exercise while monofrequent sinusoidal changes in aerobic metabolism were used as forcing signals. The following answers were derived from the simulations: 1. Non-linear distortions of the signals are negligible provided that analyses are not driven too far into the higher frequency range (periods shorter than about 1 min). 2. Variations of muscle kinetics have greater effects on pulmonary than changes of perfusion kinetics or venous volume. This finding applies irrespective of whether or not pulmonary closely reflects muscle 3. Small differences in the time constants for muscle perfusion and muscle are a major prerequisite if pulmonary , kinetics are to be taken as correct estimates of muscle kinetics. High basal muscle perfusion, small perfusion changes and small venous volumes between muscle and lungs are further factors reducing dynamic distortions of the muscle signal.  相似文献   

10.
The effect of power output increment, based on an increase in pedal rate, on blood lactate accumulation during graded exercise is unknown. Therefore, in the present study, we examined the effect of two different rates of power output increments employing two pedal rates on pulmonary ventilation and blood lactate responses during graded cycle ergometry in young men. Males (n=8) with an mean (SD) peak oxygen uptake of 4.2 (0.1) 1·min–1 served as subjects. Each subject performed two graded cycle ergometer tests. The first test, conducted at 60 rev· min–1, employed 4 min of unloaded pedaling followed by a standard power output step increment (SI) of 60 W every 3rd min. The second test, conducted at 90 rev·min–1, employed 4 min of unloaded pedaling followed by a high power output step increment (HI) of 90 W every 3rd min. Venous blood was sampled from a forearm vein after 5 min of seated rest, 4 min of unloaded pedaling, and every 3rd min of graded exercise. Peak exercise values for heart rate, oxygen uptake ( O2), and ventilation ( E) were similar (P > 0.05) for SI and HI exercise, as was the relationship between E and O2, and between E and carbon dioxide production ( CO2). However, the relationship between blood lactate concentration and O2 was dissimilar between SI and HI exercise with blood lactate accumulation beyond the lowest ventilatory equivalent of oxygen, and peak exercise blood lactate concentration values significantly higher (P < 0.05) for SI [12.8 (2.6) mmol·l–1] compared to HI [8.0(1.9) mmol·l–1] exercise. Our findings demonstrate that blood lactate accumulation and E during graded exercise are dissociated. Blood lactate accumulation is influenced by the rate of external power output increment, while E is related to O2 and CO2.  相似文献   

11.
Summary To investigate the effect of endurance training on physiological characteristics during circumpubertal growth, eight young runners (mean starting age 12 years) were studied every 6 months for 8 years. Four other boys served as untrained controls. Oxygen uptake ( O 2) and blood lactate concentrations were measured during submaximal and maximal treadmill running. The data were aligned with each individual's age of peak height velocity. The maximal oxygen uptake ( O 2max; ml · kg–1 · min–1) decreased with growth in the untrained group but remained almost constant in the training group. The oxygen cost of running at 15 km · h–1 ( O 215, ml · kg–1 · min–1) was persistently lower in the trained group but decreased similarly with age in both groups. The development of O 2max and O 215 (1 · min–1) was related to each individual's increase in body mass so that power functions were obtained. The mean body mass scaling factor was 0.78 (SEM 0.07) and 1.01 (SEM 0.04) for O 2max and 0.75 (SEM 0.09) and 0.75 (SEM 0.02) for O 215 in the untrained and trained groups, respectively. Therefore, expressed as ml · kg–0.75 · min–1, O 215 was unchanged in both groups and O 2max increased only in the trained group. The running velocity corresponding to 4 mmol · 1–1 of blood lactate ( la4) increased only in the trained group. Blood lactate concentration at exhaustion remained constant in both groups over the years studied. In conclusion, recent and the present findings would suggest that changes in the oxygen cost of running and O 2max (ml · kg–1 · min–1) during growth may mainly be due to an overestimation of the body mass dependency of O 02 during running. The O 2 determined during treadmill running may be better related to kg0.75 than to kg1.  相似文献   

12.
Summary The purpose of this investigation was to compare cardiac output ( c ) in paraplegic subjects (P) with wheelchair-confined control subjects (C) at high intensities of arm exercise. At low and moderate exercise intensity c was the same at a given oxygen uptake ( O2) in P and C. A group of 11 athletic male P with complete spinal-cord lesions between T6 and T12 and a group of 5 well-matched athletic male C performed maximal arm-cranking exercise and submaximal exercise at 50%, 70% and 80% of each individual's maximal power output (Wmax) . Maximal O2 ( O2max) was significantly lower, O2max per kilogram body mass was equal and maximal heart rate (f c) was significantly higher in P compared to C. At O2 of 1.3, 1.5 and 1.7 1-min–1, and for P 65%–90% of the O2max, c was not significantly different between the groups, although, c in P was achieved with a significantly lower stroke volume (SV) and a significantly higherf c. Although the SV was lower in P, it followed the same pattern as SV in C during incremental exercise, i.e. an increase in SV until about 45%W max and thereafter a stable SV. The similar c at a given O2 in both groups indicated that, even at high exercise intensities, circulation in P can be considered isokinetic with a complete compensation byf c for a lower SV.  相似文献   

13.
Heart diameters, heart volume (HV), PWC 130, O2 at 130 heart rate, and cardiorespiratory reactions during work at 3 kgm·s–1 were obtained in 237 boys ranging in age from 8–18 years. Results indicate that heart size, PWC 130, O130, and exercise HR, O2/HR, and SBP change significantly with age. On the other hand, HV·kg–1 and work O2, E and E/ O2 remain rather stable throughout the growth period.Correlation analysis indicates that about 85% of the observed variation in the size of the heart during growth can be accounted for by body weight, while about 70% of the variation in light submaximal working capacity ( O130) can be explained by HV alone. Holding age, height and body weight constant by partial correlation procedures yields significant relationships between HV and O130 (r = 0.461), and between HV·kg–1 and O130 (r = 0.414). Age, height, weight and size of the heart correlated simultaneously against O130 account for 75% of the variance in the dependent variable.It would seem important to suggest the need for study of the interactions between age, size and maturity, in addition to indicators of size and efficiency of the oxygen delivery system, and indices of muscle oxygen utilization efficiency. Such an approach will permit a more definite partitioning of the variance in submaximal aerobic capacity during growth, and would probably yield a more conservative estimate of the relationship between the size of the heart and submaximal working capacity during growth.Abbreviations used HV heart volume - HV·kg–1 heart volume per kg of body weight - PWC 130 physical working capacity in kgm·s–1 of work at a heart rate of 130·min–1 - O130 oxygen consumption per min at a heart rate of 130·min–1 - O2, , E, E/ O2, HR, O2/HR, SBP oxygen consumption, breathing frequency, expiratory volume, respiratory equivalent, heart rate, oxygen pulse, systolic blood pressure in the third minute of work at 3 kgm·s–1 - CA chronological age Partially supported by grants from the Kuratorium für die Sportmedizinische Forschung, Federal Republic of Germany and Laval University, Quebec, Canada  相似文献   

14.
Influence of ageing on aerobic parameters determined from a ramp test   总被引:1,自引:0,他引:1  
Summary The purpose of this study was to examine the four parameters of aerobic function, the maximum oxygen uptake ( O2max), ventilation threshold (Th VE), efficiency, and the effective time constant for oxygen consumption ( 02), across age. In particular, the study was designed to observe whether there may be accelerated declines in aerobic function beyond 60 years of age. Seventy-nine sedentary men aged 30–84 years were studied. Each subject performed two maximal cycle ramp function tests, and data were collected on a breath-by-breath basis. The O2max, from a plateau in 02, was achieved in 87% of the subjects using the ramp test. The O2max showed a significant decrease with increasing age (from linear regression,r = –0.81) at a rate averaging 0.037 l·min–1·year–1. The Th VE also declined with increasing age, but at a slower rate (0.013 l·min–1·year–1). The O2 was significantly increased across the age groups from 69 s for those aged 30–40 years to 98s for those aged 60 years or more. There was no evidence of accelerated decline in these aerobic parameters beyond age 60 years, and there were no differences in efficiency (27.5–29.9%) across age. Although other forcing functions should be used to confirm this characterization of the oxygen kinetics, this slowed response with age would result in greater oxygen deficit and possibly earlier fatigue in response to even light exercise in older individuals.  相似文献   

15.
Summary Using an open circuit system (Douglas bag method), measurement of the anaerobic threshold (AT) was performed on ten healthy male college students during an incremental exercise test on a bicycle ergometer in an attempt to determine the validity of this method as compared with arterial blood lactate AT measurement.Blood samples were taken from either the radial or brachial artery through a Teflon catheter (3 ml/each time) every minute until the subject's maximal exercise tolerance was reached. Blood lactate was analyzed by the enzymatic method.Differences in work rate, O2, % O2 max, E, HR, and R at AT LA (AT determined by the increase in blood lactate) and at AT GE (gas exchange AT based on the non-linear increases in E, CO2, and other respiratory parameters), respectively, were all found to be statistically insignificant. There was a significant correlation (r=0.866, p<0.01) between AT LA and AT GE when expressed in O2 values (l/min). There was also a significant correlation between AT LA and O2 max (r=0.778, p<0.01). These results indicate that the commonly used Douglas bag method could provide a valid non-invasive measure of anaerobic threshold.  相似文献   

16.
Summary The purpose of present study was to assess the relationship between anaerobic threshold (AT) and performances in three different distance races (i.e., 5 km, 10 km, and 10 mile). AT, O2 max, and related parameters for 17 young endurance runners aged 16–18 years tested on a treadmill with a discontinuous method. The determination of AT was based upon both gas exchange and blood lactate methods. Performances in the distance races were measured within nearly the same month as the time of experiment. Mean AT- O2 was 51.0 ml·kg–1·min–1 (2.837 l·min–1), while O2 max averaged 64.1 ml·kg–1·min–1 (3.568 l·min–1). AT-HR and %AT (AT- O2/ O2 max) were 174.7 beats·min–1 and 79.6%, respectively. The correlations between O2 max (ml·kg–1·min–1) and performances in the three distance races were not high (r=–0.645, r=–0.674, r=–0.574), while those between AT- O2 and performances was r=–0.945, r=–0.839, and r=–0.835, respectively. The latter results indicate that AT- O2 alone would account for 83.9%, 70.4%, and 69.7% of the variance in the 5 km, 10 km, and 10 mile performances, respectively. Since r=–0.945 (5 km versus AT- O2) is significantly different from r=–0.645 (5 km versus O2 max), the 5 km performance appears to be more related to AT- O2 than VO2 max. It is concluded that individual variance in the middle and long distance races (particularly the 5 km race) is better accounted for by the variance in AT- O2 expressed as milliliters of oxygen per kilogram of body weight than by differences in O2 max.  相似文献   

17.
Summary Cerebral blood flow has been reported to increase during dynamic exercise, but whether this occurs in proportion to the intensity remains unsettled. We measured middle cerebral artery blood flow velocity (m) by transcranial Doppler ultrasound in 14 healthy young adults, at rest and during dynamic exercise performed on a cycle ergometer at a intensity progressively increasing, by 50 W every 4 min until exhaustion. Arterial blood pressure, heart rate, end-tidal, partial pressure of carbon dioxide (P ETCO2), oxygen uptake ( O2) and carbon dioxide output were determined at exercise intensity. Mean vM increased from 53 (SEM 2) cm · s–1 at rest to a maximum of 75 (SEM 4) cm · s–1 at 57% of the maximal attained O2( O2max), and thereafter progressively decreased to 59 (SEM 4) cm · s–1 at O2max. The respiratory exchange ratio (R) was 0.97 (SEM 0.01) at 57% of O2maxand 1.10 (SEM 0.01) at O2max. The P ETCO2 increased from 5.9 (SEM 0.2) kPa at rest to 7.4 (SEM 0.2) kPa at 57% of O2maxand thereafter decreased to 5.9 (SEM 0.2) kPa at O2max. Mean arterial pressure increased from 98 (SEM 1) mmHg (13.1 kPa) at rest to 116 (SEM 1) mmHg (15.5 kPa) at 90% of O2max, and decreased slightly to 108 (SEM 1) mmHg (14.4 kPa) at O2max. In all the subjects, the maximal value of v m was recorded at the highest attained exercise intensity below the anaerobic threshold (defined by R greater than 1). We concluded that cerebral blood flow as evaluated by middle cerebral artery flow velocity increased during dynamic exercise as a function of exercise intensity below the anaerobic threshold. At higher intensities, cerebral blood flow decreased, without however a complete return to baseline values, and it is suggested that this may have been at least in part explained by concomitant changes in arterial PCO2.  相似文献   

18.
Summary The study was designed to investigate the age-related increase in maximal oxygen uptake with special reference to the other physiological parameters (ventilation, pulmonary diffusing capacity, cardiac output etc.). 77 normal boys aged 10–18 years were tested by the progressive loading method on a bicycle ergometer. O2 max increased by approximately 55% with age from 10–18 years. The increase in O2 max was accompanied with increase in ventilation (49%), pulmonary diffusing capacity (45%) and cardiac output (5%).  相似文献   

19.
To establish whether or not hypoxia influences the training-induced adaptation of hormonal responses to exercise, 21 healthy, untrained subjects [26 (2) years, mean (SE)] were studied in three groups before and after 5 weeks' training (cycle ergometer, 45 min· day–1, 5 days· week–1). Group 1 trained at sea level at 70% maximal oxygen uptake ( O2max), group 2 in a hypobaric chamber at a simulated altitude of 2500 m at 70% of altitude O2max, and group 3 at a simulated altitude of 2500 m at the same absolute work rate as group 1. Arterial blood was sampled before, during and at the end of exhaustive cycling at sea level (85% of pretraining of O2max). O2 increased by 12 (2)% with no significant difference between groups, whereas endurance improved most in group 1 (P < 0.05). Training-induced changes in response to exercise of noradrenaline, adrenaline, growth hormone, -endorphin, glucagon, and insulin were similar in the three groups. Concentrations of erythropoietin and 2,3-diphosphoglycerate at rest did not change over the training period. In conclusion, within 5 weeks of training, no further adaptation of hormonal exercise responses takes place if intensity is increased above 70% O2max. Furthermore, hypoxia per se does not add to the training-induced hormonal responses to exercise.  相似文献   

20.
Summary In two experiments maximal aerobic power calculated from maximal mechanical power (W max) was evaluated in 39 children aged 9–11 years. A maximal multi-stage cycle ergometer exercise test was used with an increase in work load every 3 min. In the first experiment oxygen consumption was measured in 18 children during each of the prescribed work loads and a correction factor was calculated to estimate using the equation . An appropriate increase in work rate based on height was determined for boys (0.16 W · cm–1) and girls (0.15 W · cm–1) respectively. In the second experiment 21 children performed a maximal cycle ergometer exercise test twice. In addition to the procedure in the first experiment a similar exercise test was performed, but without measurement of oxygen uptake. Calculated correlated significantly (p<0.01) with those values measured in both boys (r=0.90) and girls (r=0.95) respectively, and the standard error of estimation for (calculated) on (measured) wass less than 3.2%. Two expressions of relative work load (% and %W max) were established and found to be closely correlated. The relative work load in % could be predicted from the relative work load in % W max with an average standard error of 3.8%. The data demonstrate that calculated based on a maximal multi-stage exercise test provides an accurate and valid estimate of   相似文献   

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