Metabolic, cardiovascular, and respiratory factors in the development of fatigue in lifting tasks

1978 ◽  
Vol 45 (1) ◽  
pp. 64-68 ◽  
Author(s):  
J. S. Petrofsky ◽  
A. R. Lind
Keyword(s):  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Work Load ◽  
Specific Weight ◽  
Bicycle Ergometer ◽  
Isometric Contractions ◽  
Bicycle Ergometry ◽  
Physiological Capacity ◽  
Male Subjects ◽  
Extended Work

Three well-trained male subjects served as volunteers in these experiments to examine the physiological capacity for extended work during lifting tasks. The maximal oxygen uptake (VO2max) during lifting was always lower than work on the bicycle ergometer. However, the work load during lifting which could be maintained for 1--4 h was 50% of the VO2max for lifting each specific weight of box; the limit for lifting light boxes without fatigue was at an oxygen uptake of about 25% of the VO2max obtained from bicycle ergometry. Significant fatigue in the forearm muscles was found during prolonged lifting as assessed from the endurance of isometric contractions and from the surface electromyogram (EMG), and was more pronounced as the weight of the box increased.

BICYCLE ERGOMETER MEASUREMENT OF MAXIMAL OXYGEN UPTAKE IN CHILDREN

1967 ◽  
Vol 45 (6) ◽  
pp. 937-946 ◽  
Author(s):  
Gordon R. Cumming ◽  
Werner Friesen
Keyword(s):  
Oxygen Uptake ◽  
Pulse Rate ◽  
Maximal Oxygen Uptake ◽  
Work Load ◽  
Bicycle Ergometer ◽  
Cycle Ergometer ◽  
Uptake Curve ◽  
Exercise Tests ◽  
Straight Line ◽  
The Mean

Seven to 15 maximal exercise tests on a cycle ergometer were done on twenty boys, 11 to 15 years of age, until the work load was sufficiently high that it could not be sustained for 3 min. The mean maximal pulse rate was 202 beats/min, and the mean maximal oxygen uptake was 53.8 ml/kg per min. A plateau of the oxygen uptake curve occurred in only 7 of the 20 subjects, whereas the pulse rate reached a plateau in 13 subjects. On the basis of the pulse rate – work load straight line relationship for submaximal exercise, the intensity of the load that the subjects were able to complete was such that a mean predicted pulse rate of 247 beats/min would have resulted. This information can be utilized to obtain maximal oxygen uptake from a single test in children.

Comparison of maximal oxygen uptake values determined by predicted and actual methods

1965 ◽  
Vol 20 (3) ◽  
pp. 509-513 ◽  
Author(s):  
R. G. Glassford ◽  
G. H. Y. Baycroft ◽  
A. W. Sedgwick ◽  
R. B. J. Macnab
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Correlation Coefficients ◽  
Bicycle Ergometer ◽  
Exercise Heart Rate ◽  
Indirect Test ◽  
Physical Fitness Test ◽  
Mean Values ◽  
Fitness Test

Twenty-four male subjects aged 17–33 were given three direct tests of maximal oxygen uptake and one indirect test. The direct tests were those of Mitchell, Sproule, and Chapman (treadmill); Taylor, Buskirk, and Henschel (treadmill); and Åstrand (bicycle ergometer). The indirect test was the Åstrand-Ryhming nomogram (bicycle ergometer) employing heart rate response to submaximal work. In addition, the Johnson, Brouha, and Darling physical fitness test was administered. The two treadmill tests and the indirect test yielded significantly higher mean values than did the direct bicycle test. However no other significant differences in mean values occurred. Correlation coefficients between the various oxygen uptake tests as well as the fitness test were all found to be significant (.62–.83), i.e., greater than zero. No correlation obtained proved to be significantly greater than any other. The results indicate that direct treadmill tests, employing greater muscle mass, yield higher maximal oxygen uptake values (8%) than does the direct bicycle ergometer test. The Åstrand-Ryhming nomogram appears to produce a good estimation of maximal oxygen uptake, in a population unaccustomed to cycling. erobic capacity; exercise; heart rate Submitted on September 17, 1964

Use of respiratory quotients in assessment of aerobic work capacity

1962 ◽  
Vol 17 (1) ◽  
pp. 47-50 ◽  
Author(s):  
B. Issekutz ◽  
N. C. Birkhead ◽  
K. Rodahl
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Work Load ◽  
Work Capacity ◽  
Bicycle Ergometer ◽  
Carbon Dioxide Output ◽  
Ergometer Test ◽  
Aerobic Work Capacity ◽  
Bicycle Ergometer Test ◽  
Better Than

Oxygen uptake and carbon dioxide output were measured in 32 untrained subjects during exercise on the bicycle ergometer. It was shown that the work respiratory quotient (RQ) under standardized conditions can be used as a measure of physical fitness. ΔRQ (work RQ minus 0.75) increases logarithmically with the work load and maximal O2 uptake is reached at a ΔRQ value of 0.40. This observation offered the possibility of predicting the maximal O2 uptake of a person, based on the measurement of RQ during a single bicycle ergometer test at a submaximal load. For each work RQ between 0.95 and 1.15 a factor was presented, together with the aid of a simple equation, which gave a good approximation (generally better than ±10%) of the maximal O2 uptake.

Fibrinolytic and hemostatic changes during and after maximal exercise in males

1976 ◽  
Vol 40 (3) ◽  
pp. 287-292 ◽  
Author(s):  
G. L. Davis ◽  
C. F. Abildgaard ◽  
E. M. Bernauer ◽  
M. Britton
Keyword(s):  
Heart Rate ◽  
Factor Viii ◽  
Fibrinolytic Activity ◽  
Work Load ◽  
Bicycle Ergometer ◽  
Maximal Heart Rate ◽  
Relative Level ◽  
Maximum Exercise ◽  
Activity Factor ◽  
Male Subjects

To evaluate changes in fibrinolytic activity, factor VIII and other hematological variables during and after a progressive step increment in work load, 10 healthy male subjects (22–27 yr of age) were exercised to exhaustion on an electromagnetic bicycle ergometer. Blood samples were drawn serially throughout the experiment. Little change in fibrinolytic activity was observed before 70–80% maximum heart rate (MHR) was achieved. Major changes occurred after 80% MHR. Peak values coincided with maximum exercise. In contrast major changes in factor VIII were observed between 95 and 100% MHR with peak values occurring 5–10 min postexercise. An increase in white blood cell count, platelet count, and retention was observed at maximum exercise. One individual failed to demonstrate an increase in either fibrinolytic or factor VIII activity. Relating the data to either the percent maximal oxygen uptake or percent maximal heart rate demonstrates the importance of the exercise protocol and exerting all subjects to the same relative level of physiological work.

Mean myoglobin oxygen tension during exercise at maximal oxygen uptake

1975 ◽  
Vol 39 (1) ◽  
pp. 135-144 ◽  
Author(s):  
B. J. Clark ◽  
R. F. Coburn
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Uptake ◽  
Aerobic Capacity ◽  
Maximal Oxygen Uptake ◽  
Bicycle Ergometer ◽  
Limiting Factors ◽  
Considerable Variability ◽  
Vo2 Max ◽  
The Subject ◽  
Total Body

Changes in intracellular Po2 in myoglobin containing skeletal muscle during exercise were estimated in normal nonathlete subjects from measurements of shifts of CO between blood and muscle under conditions where the total body CO stores remained constant. Exercise was performed on a bicycle ergometer. In 1.5–2 and 6–7 min runs at Vo2 max with the subject breathing 21% O2, mean MbCO/HbCO increased 146 +/- 7 and 163 +/- 11% of resting values, respectively (P less than 0.05). With the subjects breathing 13–14% O2, in 1.5–2 and 6–7 min runs, Vo2 max fell an average of 4.3 +/- 5.1% and 12.0 +/- 5.2%, respectively, and mean MbCO/HbCO increased to 233 +/- 18% and 210 +/- 52% of resting value, respectively (P less than 0.05). These findings suggest that mean myoglobin Po2 fell during exercise at Vo2 max, with the subjects breathing 21% O2 and the decrease in mean myoglobin Po2 was greater with the subject breathing 13–14% O2. There was considerable variability in different subjects and in some, the data were not consistent with intracellular O2 availability limiting aerobic metabolism. The data support a postulate that there are several limiting factors for the aerobic capacity, including intracellular O2 availability.

#1 EFFECTS OF THE FORWARD LEAN POSITION AND THE USE OF TOE CLIPS ON MAXIMAL OXYGEN UPTAKE DURING BICYCLE ERGOMETRY

1981 ◽  
Vol 13 (2) ◽  
pp. 123 ◽  
Author(s):  
M. S. Bateman ◽  
N. K. Butts ◽  
D. G. Wussow ◽  
D. T. Kirkendall ◽  
J. Santiesteban
Keyword(s):  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Bicycle Ergometry

Effect of Low- and High-Carbohydrate Diets on the Plasma Glutamine and Circulating Leukocyte Responses to Exercise

1998 ◽  
Vol 8 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Michael Gleeson ◽  
Andrew K. Blannin ◽  
Neil P. Walsh ◽  
Nicolette C. Bishop ◽  
Anya M. Clark
Keyword(s):  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Plasma Cortisol ◽  
Prolonged Exercise ◽  
Normal Diet ◽  
Strenuous Exercise ◽  
Glutamine Concentration ◽  
High Carbohydrate ◽  
Low Carbohydrate ◽  
Male Subjects

We examined the effects of a low-carbohydrate (CHO) diet on the plasma glutamine and circulating leukocyte responses to prolonged strenuous exercise. Twelve untrained male subjects cycled for 60 min at 70% of maximal oxygen uptake on two separate occasions, 3 days apart. All subjects performed the first exercise task after a normal diet: they completed the second exercise task after 3 days on either a high-CHO diet (75±8% CHO, n = 6) or a low-CHO diet (7±4% CHO, n = 6). The low-CHO diet was associated with a larger rise in plasma cortisol during exercise, a greater fall in the plasma glutamine concentration during recovery, and a larger neutrophilia during the postexercise period. Exercise on the high-CHO diet did not affect levels of plasma glutamine and circulating leukocytes. We conclude that CHO availability can influence the plasma glutamine andcirculaling leukocyte responses during recovery from intense prolonged exercise.

Maximal heart rate during work in older men

1959 ◽  
Vol 14 (4) ◽  
pp. 562-566 ◽  
Author(s):  
Irma Åstrand ◽  
Per-Olof Åstrand ◽  
Kaare Rodahl
Keyword(s):  
Heart Rate ◽  
Ambient Air ◽  
Work Load ◽  
Work Capacity ◽  
Bicycle Ergometer ◽  
Maximal Heart Rate ◽  
Average Maximum ◽  
Work Up ◽  
Aerobic Work Capacity ◽  
Male Subjects

Nine 56–68-year-old male subjects performed muscular work up to maximal loads on a bicycle ergometer while breathing both ambient air and oxygen. Heart rate increased to an average maximum of 163/min. The maximal O2 intake averaged 2.24 l/min. and the blood lactic acid concentration 85 mg/100 ml. In no case was the maximal heart rate higher when breathing O2 than when breathing air. This low maximal heart rate in older people probably limits the capacity for O2 intake. Four subjects were able to work for about 1 hour without any sign of exhaustion on a work load requiring an O2 consumption of about 50% of their maximal aerobic work capacity. Submitted on October 3, 1958

Renal clearances during prolonged supine exercise at different loads

1965 ◽  
Vol 20 (6) ◽  
pp. 1294-1298 ◽  
Author(s):  
Gunnar Grimby
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Work Capacity ◽  
Bicycle Ergometer ◽  
Work Intensity ◽  
Arterial Blood ◽  
Renal Clearances ◽  
Heavy Work ◽  
Aerobic Work Capacity ◽  
Male Subjects

Clearance of inulin (CIn) and para-aminohippuric acid (CPAH), cardiac output, oxygen uptake, and arterial blood pressure were measured in 15 healthy male subjects at rest and during supine exercise of 45 min duration on a bicycle ergometer. Work loads between 150 and 900 kpm/min were chosen. CPAH decreased with increasing work intensity (heart rate). At an oxygen uptake corresponding to half of the aerobic work capacity it was about 70% and at heavy work 35–45% of the value at rest. The renal fraction of the cardiac output averaged, at rest, 17% and decreased with increasing work loads to 2.5–5% as a minimum. CIn did not change significantly until heavy exercise was performed. The filtration fraction increased during exercise. clearances of inulin and para-aminohippuric acid; cardiac output Submitted on May 28, 1965

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