The main hypothesis of this thesis was that the regulation of oxygen uptake (VO2) kinetics at the onset of exercise in trained young men is linked to cardiovascular adaptations. Two studies were conducted to investigate the interrelationships between oxygen (O2) transport and O2 utilization in accelerating VO2 kinetics at the onset of exercise. In the first study, simultaneous kinetics of VO2 and cardiac output (Q) were studied during the transition to heavy and moderate cycling exercise (Chapter 2). The acceleration of VO2 kinetics during the heavy exercise that followed prior moderate or heavy exercise was enabled by the rapid increase in Q; whereas, the acceleration of VO2 kinetics during moderate exercise that followed a heavy warm-up was associated with small changes in Q kinetics. The objective of the second study was to determine, in a model of forearm exercise, if the elevation of forearm blood flow (FBF) prior to the onset of exercise by prior circulatory occlusion would accelerate FBF and muscle oxygen uptake (VO2mus)kinetics during subsequent exercise as demonstrated previously for prior exercise (Chapter 3). Prolonged ischemia (15 min occlusion) followed by 3 min recovery reduced FBF and impaired VO2mus kinetics during subsequent heavy hand-grip exercise. However, prior heavy exercise confirmed the previous findings and resulted in a faster FBF and VO2mus kinetics. There was a high positive correlation between the time course of change in FBF and VO2mus at the onset heavy exercise. In a follow up of the second study, to investigate a possible mechanism for the slower adaptation of VO2mus following ischemia, the prior occlusion condition was repeated after ingesting a high dose of ibuprofen. Prostaglandin inhibition by ibuprofen augmented the FBF response during reactive hyperaemia and restored FBF during the heavy exercise that followed 15 min of circulatory occlusion to the control level. These two studies provide evidence that O2 delivery plays a dominant role in accelerating VO2 kinetics at the onset of heavy exercise in trained young men. The findings exposed differences in the mechanisms regulating pulmonary VO2 and VO2mus with prior exercise resulting in higher Q and FBF, but no changes in O2 extraction to yield the faster increase in pulmonary VO2 and VO2 at the onset of subsequent heavy exercise. In contrast, prior occlusion slightly retarded the increase in FBF and significantly reduced O2 extraction thus delaying VO2 kinetics. The precise mechanisms impairing VO2mus kinetics at the onset of heavy forearm hand-grip exercise that starts after a brief recovery from prolonged occlusion are still unknown, but this impairment may be partially due to a vasoconstrictor effect restricting blood flow during the adaptation to exercise and redistribution of the blood to the periphery. In a third study, the influence of muscle activity on the VO2 slow component during heavy exercise and O2 cost during moderate exercise that followed a heavy warm-up were examined (Chapter 4). The heavy exercise VO2 slow component was attenuated in a graded fashion by prior moderate and heavy warm-ups, and the principal components analysis showed a moderate but significant correlation between the changes in the integrated electromyographic activity and the VO2 slow component amplitude. The higher O2 cost of moderate exercise following a heavy warm-up was associated with higher mean power frequency. Changes in VO2 slow component and increased O2 cost during moderate exercise after prior heavy warm-up appear to be related to some changes in surface electromyographic activity which may provide some evidence for increased muscle fibres recruitment.

The main hypothesis of this thesis was that the regulation of oxygen uptake (VO2) kinetics at the onset of exercise in trained young men is linked to cardiovascular adaptations. Two studies were conducted to investigate the interrelationships between oxygen (O2) transport and O2 utilization in accelerating VO2 kinetics at the onset of exercise. In the first study, simultaneous kinetics of VO2 and cardiac output (Q) were studied during the transition to heavy and moderate cycling exercise (Chapter 2). The acceleration of VO2 kinetics during the heavy exercise that followed prior moderate or heavy exercise was enabled by the rapid increase in Q; whereas, the acceleration of VO2 kinetics during moderate exercise that followed a heavy warm-up was associated with small changes in Q kinetics. The objective of the second study was to determine, in a model of forearm exercise, if the elevation of forearm blood flow (FBF) prior to the onset of exercise by prior circulatory occlusion would accelerate FBF and muscle oxygen uptake (VO2mus)kinetics during subsequent exercise as demonstrated previously for prior exercise (Chapter 3). Prolonged ischemia (15 min occlusion) followed by 3 min recovery reduced FBF and impaired VO2mus kinetics during subsequent heavy hand-grip exercise. However, prior heavy exercise confirmed the previous findings and resulted in a faster FBF and VO2mus kinetics. There was a high positive correlation between the time course of change in FBF and VO2mus at the onset heavy exercise. In a follow up of the second study, to investigate a possible mechanism for the slower adaptation of VO2mus following ischemia, the prior occlusion condition was repeated after ingesting a high dose of ibuprofen. Prostaglandin inhibition by ibuprofen augmented the FBF response during reactive hyperaemia and restored FBF during the heavy exercise that followed 15 min of circulatory occlusion to the control level. These two studies provide evidence that O2 delivery plays a dominant role in accelerating VO2 kinetics at the onset of heavy exercise in trained young men. The findings exposed differences in the mechanisms regulating pulmonary VO2 and VO2mus with prior exercise resulting in higher Q and FBF, but no changes in O2 extraction to yield the faster increase in pulmonary VO2 and VO2 at the onset of subsequent heavy exercise. In contrast, prior occlusion slightly retarded the increase in FBF and significantly reduced O2 extraction thus delaying VO2 kinetics. The precise mechanisms impairing VO2mus kinetics at the onset of heavy forearm hand-grip exercise that starts after a brief recovery from prolonged occlusion are still unknown, but this impairment may be partially due to a vasoconstrictor effect restricting blood flow during the adaptation to exercise and redistribution of the blood to the periphery. In a third study, the influence of muscle activity on the VO2 slow component during heavy exercise and O2 cost during moderate exercise that followed a heavy warm-up were examined (Chapter 4). The heavy exercise VO2 slow component was attenuated in a graded fashion by prior moderate and heavy warm-ups, and the principal components analysis showed a moderate but significant correlation between the changes in the integrated electromyographic activity and the VO2 slow component amplitude. The higher O2 cost of moderate exercise following a heavy warm-up was associated with higher mean power frequency. Changes in VO2 slow component and increased O2 cost during moderate exercise after prior heavy warm-up appear to be related to some changes in surface electromyographic activity which may provide some evidence for increased muscle fibres recruitment.

During, the Churchill Coalition, 1940-45, there developed within tile Government a coherent thesis that the Soviet Union would follow a post-war policy of cooperation with Britain. Soviet foreign policy-makers were perceived to have till-cc options; isolation, enmity or collaboration. Three central perceptions produced tile theory that cooperation was the likely choice. The first that developed, from 1940, was the view that Soviet aims were limited, largely defensive, and not likely to impinge upon areas of vital British interest. Far from desiring to propagwie world revolLitioii, Stalin simply wanted protection, particularly against a resurgent Germany, to continue the internal development of industrialization and state socialism interrupted by the war. After Barbarossa, the immense task of Soviet reconstruction became a second factor. Even if the USSR attempted to do this without foreign help, its rulers would seek tile cheapest possible foreign policy to enable them to coriccritratc on it: collective security in cooperation with Britain and possibly the USA. Third, Stalin was now secii iis it wise, realist statesman who had become persuaded of the wisdom of a cooperation policy will, the West. Linked with these assumptions were conclusions drawn from observations of changes in the USSR in the war, especially the revivill of nationalism, and from observation of the sensitivity of Soviet leaders. Debate on these percept ions and tile policy that should follow chiefly took place within the 1,0 departments, between thern and their ambassadors in Moscow and other places, with the military, and intermittently in Cabinet. Ilowevcr, while a policy combining "firmness" and "frankness" was preferred by most, considerations of Soviet sensitivity meant it wits never I'Llily implemented. Thus in February 1945, there was a rough consensus that [lie Soviets would try cooperation, but there was uncertainty as to the optimum British policy to maximise the chances of securing it.

No description available.

Exercise training represents a potent stimulus to the parameters of aerobic and anaerobic fitness in adults; whether the same is true in young girls is unclear. For some parameters, such as peak oxygen uptake, the influence of training status remains controversial whilst for other parameters, such as oxygen uptake kinetics, the influence of training status remains simply uninvestigated in young girls. Despite this lack of empirical evidence, it has been suggested for some time now that children may lack trainability and that this may be related to the presence of a maturational threshold below which significant adaptations to training cannot occur. This suggestion requires investigation, not least because the findings of some studies which appear to support this contention may in reality be a reflection of the use of an inappropriate test modality for the investigation of training status influences. The purpose of this thesis was therefore to determine the physiological trainability of girls at different stages of maturation and to investigate the interaction between training status, maturity and exercise modality. To achieve this purpose a series of 5 studies was completed, in which trained and untrained girls completed ramp incremental exercise, constant-work-rate exercise and Wingate exercise on two exercise modalities, one upper (arm crank) and one lower body (cycle). During these tests, cardiovascular, respiratory, metabolic and mechanical power parameters were assessed. In response to ramp incremental exercise, trained girls were shown to have a higher peak O2, SV and at all stages of maturity, along with an altered SV and fractional muscle oxygen extraction pattern, irrespective of exercise modality. The importance of exercise modality was evident during heavy intensity constant-work-rate exercise in pre-pubertal girls, where training status was only associated with significant influences on O2 kinetics (faster phase II time constant in trained girls) during upper body ergometry. In contrast, pubertal trained girls had faster O2 kinetics during both exercise modalities, an influence which may suggest both central and peripheral adaptations to the delivery and utilisation of oxygen. Exercise modality was also revealed to be an important factor in the demonstration of training status influences during a 30 s Wingate test, with trained girls at all stages of maturity exhibiting higher mechanical power indices during upper body ergometry only. An influence of training status was also evident in the lower fatigue index found in the trained girls at all stages of maturity during both modalities, but no influence was found in the oxidative contribution to the Wingate test. None of these studies revealed an influence of maturity status in determining the magnitude of training status effects. Overall, the 5 studies encompassed within this thesis demonstrate that children are trainable and that this is not moderated by maturity.

There is growing concern that many children in Britain do not take sufficient exercise to benefit cardiovascular health. This is supported by extensive evidence advocating the importance of regular physical activity for lifelong health and well-being, and is of particular relevance in Scotland given it's notorious record of adult coronary heart disease death. This study examined aspects of fitness and physical activity in groups of Edinburgh school children, aged between 13 and 14 years. A three stage investigation was adopted: Phase One: A repeated measures, same subject design was used to examine the reliability and validity of selected measures (20m shuttle run test, peak oxygen uptake (V02 Peak), and anthropometric measures). Thirty three children (15 boys, 18 girls) performed each test on 3 separate days. Anthropometric measures showed strong reliability (r > 0.94, n=33) whilst reliability for the treadmill test ofV02 peak and shuttle run performance was lower (r=0.89 and r=0.79 respectively). Multiple regression analysis yielded a new equation for predicting V02 peak for children. This age specific prediction equation incorporated shuttle run performance in conjunction with skinfold thickness measures (Boys, R2=0.64 SEE=3.46; Girls, R2=0.79, SEE=2.81). Repeat testing was also recommended. Phase Two: An evaluation of methods of heart rate data analysis to assess physical activity in children. Twenty eight children (14 boys, 14 girls) wore continuous heart rate monitors (polar Electro PE4000, Finland) over a period of 7 days (Monday to Sunday), mean duration 737 (+/-55) mins/day. A detailed 7 day self report activity diary was also completed. Variability of heart rate measures was high (R=0.10-0.30), and it was noted that using data for just 4 days or less resulted in considerable underestimation of total weekly activity levels (44-100% error). If activity levels are to be compared against current recommendations, researchers must endeavour to achieve weekly rather than daily estimates of activity. Evaluation of methods of heart rate data analysis showed good correlation between heart rate activity indices and reported seven day activity. For boys strongest correlation was achieved using the number of 5 minute periods with HR > 139 b.min"l and the number of 5 minute periods with HR > 50% heart rate reserve (r=0.80, n=14). Total activity time was similar for both males and females but girls engaged in fewer sustained bouts of activity (>5 minutes) and a better correlate with activity in females was achieved using the total number of elevated heart rates (total HR > 50% heart rate reserve, r=0.64, n=14). Phase Three: A cross sectional survey was conducted to investigate standards of aerobic fitness and patterns of physical activity in groups of Edinburgh school children. Height, weight, skinfold thickness, shuttle run performance and physical activity (assessed by heart rate monitoring and activity diary) were recorded in a sample of 91 children (44 Boys, 47 Girls). Overall, males performed significantly better on the shuttle run test (t=5.4, df=88, p < 0.05), had higher predicted peak oxygen uptake (t=5.6, df=87, p < 0.05), and engaged in more bouts of moderate to vigorous activity than females. Seventy percent of boys and 50% of girls fulfilled current physical activity guidelines. Most activities were school based (131 mins per week as compared to 85 mins per week of out of school activities). Activity tended to be sporadic with active days interspersed with inactive days (mean 3.2 +/·1.6 days per week). After school activities specifically targeting young girls should be promoted.

To develop reference standards for cardiorespiratory fitness (CRF) from directly measured maximum oxygen consumption using the Ball State University Adult Physical Fitness Program (APFP) cohort. The APFP cohort is an open cohort of self-referred participants since 1971. From 3,212 individual participants, 2,642 male and 1,741 female (18-79 years) test files remained after exclusion criteria was met. Gender-specific age, physical activity (PA), body mass index (BMI), and smoking status CRF reference standards were developed. Men had greater mean CRF (35%) than women and consistently had greater mean CRF according to age, PA, BMI, and smoking status (p<.05). CRF was approximately 10% lower across each decade of age, and was greater with increasing PA compared to the sedentary group. Greater classes of BMI had lower CRF, and CRF was 5% greater in non-smokers compared to current smokers. A pooled CRF registry is recommended for a larger and more diverse cohort. / School of Physical Education, Sport, and Exercise Science

No description available.

No description available.

Master of Science / Department of Kinesiology / Thomas J. Barstow / Purpose: Oxygen uptake (VO2) has been shown to be controlled by a nonlinear system, yet the VO2 response to ramp style exercise appears linear. We tested the hypothesis that an integrative model incorporating nonlinear parameter values could accurately estimate actual VO2 responses to ramp style exercise. Methods: Six healthy, men completed three bouts of varying ramp rate exercise (slow ramp (SR): 15 W/min, regular ramp (RR) 30 W/min, fast ramp (FR) 60W/min) and four bouts of extended-step incremental exercise, where each step lasted 5-15 min or until volitional fatigue on a cycle ergometer on separate days. The step-responses were then fit with a simple monoexponential starting at time zero (MONO) or allowing a time delay and using only the first 5 min of data (5TD). The resulting VO2 parameters from the step protocol were incorporated into an integrative model for the estimation of the VO2 response to each of the rates of ramp incremental exercise. The parameters from the actual and model ramp protocols were compared with 2 way repeated-measures ANOVAs. Results: Both Gain (G) and Mean Response Time (MRT) (or time constant) values increased significantly across work rate transitions (mean±SD; Gain:10.0±0.9, 11.6±1.1, 13.1±1.3, 17.6±3.3 ml O2/min/W; MRT:39.4±7.7, 54.0±5.4, 79.6±15.0, 180.1±56.2 s). Up to maximalVO2 the models over-estimated the actual VO2 response for FR (Gain: ACT 8.7±1.0, MONO 9.9±0.4, 5TD 10.3±0.3 ml O2/min/W). Up to 80% maximal VO2 the models accurately predicted the actual VO2 response across all ramp rates (Gain: ACT 10.7±1.1, 10.2±0.5, 9.2±1.0; MONO 11.0±0.8, 10.3±0.6, 9.2±0.5; 5TD 10.4±0.4, 10.2±0.3, 9.8±0.2 ml O2/min/W, values are listed SR,RR,FR). Conclusions: When variable parameter values (G and either MRT or time constant and time delay) were utilized by an integrative model, accurate estimations of the VO2 response to ramp incremental exercise were possible regardless of ramp rate (up to 80% maximal VO2). The increases in both G and MRT (or time constant) appear to balance each other to produce the quasi-linear VO2 responses.