摘要:

ABSTRACT.Hormonal and metabolic responses to submaximal exercise were studied in eight normal subjects. Four subjects had high maximal oxygen uptakes (4.55 ± 0.49 1/min) and were classified as “fit” and four had low maximal oxygen uptakes (2.13 ± 0.32 1/min) and were classified as “unfit.” All subjects exercised for 20 minutes at 750 kpm/min on a cycle ergometer, which represented 35% and 85% of the maximal oxygen uptake for the fit and the unfit subjects respectively. The unfit subjects had a higher heart rate and CO2output at the same oxygen uptake when compared with the fit group. There was a high blood lactate in the unfit subjects and also a greater rise in blood glucose, plasma cortisol and serum growth hormone during exercise in these subjects. Free fatty acids increased in the fit subjects, but not in the unfit and serum insulin was depressed in both groups. Thus, the cardiorespiratory fitness is an important determinant of the hormonal and metabolic response to submaximal exercise, which differed considerably when fit and unfit subjects exercised at identical absolute levels of power output. These differences have implications for the control of energy substrates used during exercise.

ISSN:0025-7990    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

ABSTRACT.Twelve male subjects were compared on continuous and intermittent treadmill test of identical exercise stages. Each stage was three minutes in duration. Oxygen uptake during minutes one and two was significantly lower in the intermittent test. Heart rate, VEand R were lower and oxygen pulse greater during all three minutes at moderate and strenuous workloads and throughout recovery of the intermittent protocol. There were no significant differences in exercise minute three or recovery &OV0312;o2, and blood pressure. Regression equations for the relationship between &OV0312;o2, oxygen pulse, heart rate, &OV0312;E, systolic blood pressure and workload during the third minute of exercise included curvilinear functions, whereas the regression equations between &OV0312;o2and heart rate, and between R and workload were linear. Slopes of percent maximal heart rate vs. percent maximal &OV0312;o2of the third minute were not different. Heart rate responded more rapidly to onset and cessation of exercise than did &OV0312;o2. A near steady state was obtained during low and moderate workloads prior to minute three supporting the feasibility of reducing test time. Results suggest a slight advantage in intermittent testing compared to continuous testing for evaluating cardiovascular function and for exercise prescription.

ISSN:0025-7990    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

ABSTRACT.Fifteen experienced weight lifters were investigated to examine the effects of weight exercise with variable intensity on heart rate and changes in arterial glucose, lactate and pyruvate, as well as serum total lipids, &bgr;‐lipoproteins, triglycerides, glycerol and free fatty acids. The highest value of heart rate were reached during repetitions (ca. 150 beats/min), during single maximal contraction only 120 ‐ 130 beats/min. No important changes were found in lipid substrates or glucose, while lactate (&OV0398; max: 4 mmol/l) and pyruvate (&OV0398; max: 0.11 mmol/l) increases were moderate. This type of training may be useful in the clinical rehabilitation of the locomotor system but it lacks importance for preventive or rehabilitation therapy of the cardiovascular system.

ISSN:0025-7990    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

ABSTRACT.To further evaluate the specificity of aerobic training, maximum physiologic measures (&OV0312;O2, &OV0312;E, HR, and R) and submaximal exercise heart rate were determined in control (N = 8) and experimental (N = 11) subjects prior to and following 10‐week interval run training. Experimental subjects significantly increased (P<0.01) treadmill &OV0312;O2max by 252 ml O2or 6.3%. This was significantly larger (P<0.01) than the 87 ml O2or 2.6% increase (P<0.05) observed during swimming. Max HR decreased significantly in both forms of exercise. In addition, heart rate at two submaximal work levels during running and swimming was significantly lower after training. No changes in metabolic and physiologic measures were demonstrated for the controls after the 10‐wk period. These results further support the concept of the specificity of the metabolic adaptation to aerobic training and strongly suggest that local adaptations in skeletal muscle significantly contribute to improvements in &OV0312;O2max. However, running may produce a general training adaptation in maximal and submaximal heart rate.

ISSN:0025-7990    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

ABSTRACT.Component and resultant external forces and torques at ankle, knee, and hip joints of unrestrained lower extremity motion were computed as resultant limb velocities were systematically changed. Cinematographic and modeling techniques were used to analyze 45 trials of five skilled soccer players who performed slow, medium, and fast velocity kicks. A model of the lower extremity was incorporated, with kinematic data and segment mass estimates, into computer programs to quantify the mechanical variables. Monotonic increases in magnitudes of all kinetic elements occurred as the velocity of kicking was increased. Significant differences were also observed in the maximum values of the net parallel and perpendicular external force actions, and resultant torques at the joints with changes in limb velocity.

ISSN:0025-7990    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

ABSTRACT.The present investigation determined the efficacy of progressively increased pedalling rate (P) or resistance (R) during assessment of maximal oxygen uptake (&OV0312;o2max) on the bicycle ergometer. Twenty male and nine female university students performed randomly assigned discontinuous P and R maximal stress tests. Male subjects immedicately repeated each test within the same experimental session. Regardless of test protocol, &OV0312;o2max was quite similar. Magnitude estimates of perceived effort were significantly lower for male subjects during P testing (P<.05) and 80% of male subjects preferred P testing. Conversely, magnitude estimates were significantly lower for female subjects for R testing (P<.05). P testing could be reliably repeated within the same experimental session whereas with R testing, &OV0312;o2max was significantly reduced (P<.05). It was concluded that progressively increased pedalling rate offers a physiologically acceptable means to Vo2max assessment on the bicycle ergometer for males and females. In addition, progressively increased pedalling rate offers a perceptually preferable means to &OV0312;o2max assessment for males but not for females.

ISSN:0025-7990    

出版商:OVID    

年代:1978

数据来源: OVID

ISSN:0025-7990    

出版商:OVID    

年代:1978

数据来源: OVID