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.

Sprint interval training (SIT) increases peak oxygen uptake (VO2peak) but the mechanistic basis is unclear. The Fick principle broadly attributes increases in VO2peak to changes in peak cardiac output (Qpeak) and/or peak arteriovenous oxygen difference (peak a-vO2diff). The main purpose of this thesis was to investigate the role of Qpeak, measured non-invasively using inert gas rebreathing (IGR), on SIT-induced changes in VO2peak. It also considered the time course of these responses and the influence of biological sex. The SIT protocol involved 3 x 20-s “all out” sprints performed within a 10-min session of low-intensity cycling. Study 1 measured Qpeak after 2, 6, and 12 weeks of SIT and found it was increased after 12 weeks and associated with the change in VO2peak. Peak a-vO2diff, estimated based on the Fick equation (peak a-vO2diff = VO2peak/Qpeak), was also increased after SIT and associated with the change in VO2peak. Study 2 found that a novel constant-load protocol elicited Qpeak values that were non-inferior to an established step protocol, within a margin of 0.5 L/min. Both protocols elicited VO2 values at Qpeak that were similar to VO2peak. The constant load protocol had similar day-to-day repeatability as the VO2peak test (typical error = 6.6 and 6.4%, respectively). Study 3 investigated an exploratory finding from Study 1 that suggested Qpeak was increased in male but not female participants. The design was similar, but Study 3 employed suggested best practices for making sex-based comparisons. Contrary to our hypothesis, Qpeak was unchanged after 12 weeks of SIT and there was no sex-based difference. Like Study 1, peak a-vO2diff was increased and correlated with VO2peak. This thesis advances knowledge regarding the influence of SIT on Qpeak determined non-invasively and highlights the need for more mechanistic work to comprehensively assess the basis for the increase in VO2peak. / Thesis / Candidate in Philosophy / Sprint interval training (SIT) is a form of exercise that involves brief bursts of near-maximal to “all out” efforts separated by short recovery periods. The method improves cardiorespiratory fitness — an important health marker that is quantified as the highest amount of oxygen used by the body during strenuous exercise (VO2peak) — but the mechanisms are not well understood. This thesis examined the effect of SIT on peak cardiac output (Qpeak), which is the highest rate of blood pumped by the heart each minute, and the relationship to changes in VO2peak. Qpeak was measured non-invasively by having participants breathe an inert gas mixture. Two separate 12-week training studies confirmed that SIT increased VO2peak but yielded conflicting results regarding the role of Qpeak. The findings also suggest that the capacity of skeletal muscles to extract oxygen is increased after SIT. Biological sex does not appear to influence SIT-induced changes in Qpeak or VO2peak.

Measuring V02peak is an important health assessment used to indicate cardiorespiratory fitness, prescribe exercise, and diagnose heart abnormalities (2,12). Utilizing the muscles of the upper body, the new StairMaster kayak ergometer is ideal for measuring V02peak on people with lower extremity disorders and those whose occupational or recreational activities rely primarily on the muscles of the upper body (16). Twenty-four healthy college-aged (17-31 years) males and females were screened, gave informed consent, and received orientation to experimental procedures prior to participation in the study. Subjects performed two maximal exercise bouts on the kayak incremental protocol and one on the treadmill incremental protocol. Pearson's r correlation estimated the stability-reliability coefficient of the kayak protocol to be 0.84. Pearson's r correlation estimated the relationship of the kayak protocol to the treadmill protocol to be 0.69. Given performance on the kayak ergometer, the predictive equation for treadmill performance was Y = 11.2605 + 1.02748X (r = 0.48). Body mass index and forearm circumference were found to be adequate predictors of kayak performance using the equation 45.2 - 1.60 BMI + 1.03 Forearm (~ 0.49). Although the kayak incremental protocol demonstrates adequate test-retest reliability for measuring V02peak, it has only a fair relationship to the gold standard of uphill treadmill running. The kayak incremental protocol, therefore, is generally best suited for those who, due to lower extremity complications, are unable to perform traditional modes of testing, or for those whose occupational or recreational activity is dominated by the upper body. / Master of Science

Rating of Perceived Exertion (RPE) relates to how ‘hard’ or ‘easy’ an exercise feels. The Borg 6-20 RPE scale is the most widely used scale to estimate the overall, peripheral and central perception of effort. To date, there are a limited number of studies on the use and efficacy of perceived exertion in persons with spinal cord injury and/or disease. The findings from these studies are also equivocal. Therefore, the aims of this thesis were to assess: i) the relationship between the RPE and physical and physiological markers of exercise intensity during arm cranking exercise in able-bodied and individuals with spinal cord disease, ii) the efficacy of sub-maximal RPE values to predict peak oxygen uptake during arm cranking exercise in able-bodied and paraplegic individuals using different exercise protocols, iii) the scalar property of the RPE during arm cranking exercise in able-bodied and paraplegic individuals. To achieve these goals, the thesis has been broken down to a series of seven studies. In each of these studies, except study 6, a group of able-bodied and a group of paraplegic participants were recruited to asses these hypotheses. Paraplegic individuals had spinal cord injury with neurological levels at or below the sixth thoracic vertebra (T6) or flaccid paralysis as a result of poliomyelitis infection. These individuals were physically active and participated in sports like wheelchair basketball, weightlifting, wheelchair racing and table tennis at both professional and recreational levels. Able-bodied participants were healthy and free from pre-existing injuries and physically active but not arm-trained. There were strong relationships between the RPE and each of the physiological and physical indices of exercise intensity during arm cranking exercise regardless of group or gender. Peak oxygen uptake can be predicted with reasonable accuracy from sub-maximal oxygen uptake values elicited during a sub-maximal perceptually-guided, graded exercise test for paraplegic individuals but not for able-bodied participants. It has also been shown that peak oxygen uptake can be predicted from power output using the equation prescribed by the American College of Sports Medicine (ACSM, 2006). Furthermore, for able-bodied participants using estimation procedures, a passive process in which an individual is asked to rate how ‘hard’ or ‘easy’ an exercise feels, the ramp exercise test provided more accurate prediction of peak oxygen uptake compared to the graded exercise test. For paraplegic persons using estimation procedures, the graded exercise test provided more accurate prediction of peak oxygen uptake compared to the ramp exercise test. Finally, the scalar property of the RPE (i.e., similar proportions of time at a given RPE) was evident during arm cranking exercise regardless of group. In conclusion, the prediction of peak oxygen uptake from sub-maximal exercise tests would provide a safer environment of exercise testing. In addition, using a sub-maximal protocol would make peak oxygen uptake more available for sedentary and clinical population compared to the graded exercise test to volitional exhaustion. Prediction of peak oxygen uptake from power output using the ACSM equation would make the estimation of peak oxygen uptake more available for large groups of people. Similar proportions of time were observed at a given RPE regardless of group or exercise intensity. The early RPE responses will give an indicator for how long a participant is going to exercise. This has important implications for rehabilitation settings. Based on the RPE responses the tester or the observer can increase or decrease the work rate to enable the participant to exercise for the desired duration.

The purpose of this study was to predict VO2pak using ratings of perceived exertion (RPE), heart rate (HR), and percent fat (PFAT). Subjects were males (n= 60) (PFAT, M SD = 14.4 6.1) and females (n= 67) (PFAT, M SD = 23.4 4.9) with ages ranging from 18 to 33 years. Subjects performed an incremental cycle ergometer protocol and RPE, HR and Vo2 were measured at each stage until VO2 ak was achieved. Mean RPE and HR at the submaximal workload of 100 watts were, (RPE100) M= 12.7 2.6 and (HR100) M= 146.924.7 respectively. Correlations (p< .001) with VO2p. were -.75 (PFAT), -.66 (HR100), -.67 (FIPE100). The multiple correlation using PFAT, HR100, and RPE100 as predictors of VO2pak was .83 (SEE= 5.28 ml-kg BW'smin"). Each predictor contributed to the correlation (p<.01). The results indicate that PFAT combined with exercise responses of RPE and HR provide valid estimates of VO2peak with a relatively small SEE.

Peak oxygen uptake (VO2PEAK) in endurance exercise trained (ET =8) subjects (VO2PEAK = 61.7 1.6 ml 02.kg.min-1) was compared to the V02 PEAK of untrained (UT = 8) subjects (V02 PEAK = 38.4 1.7 ml 02 -kg.min1) after four hours of -6* head-down rest (HDR).Although both groups showed a reduction in blood volume (BV) following HDR, this decrement was greater for ET subjects (delta BV = -3.23 0.46 mi/kg; P <0.05). The ET subjects had a greater decrease in VO2=(delta 02E -5.58 1.05 ml 02-kg.min-1; P <0.05) than their UT peers (VO2PEAK = -2.44 0.79 ml02-kg.min-1). These data suggest that the greater reductions in VO2PE, observed for the ET group were associated with a greater BV loss resulting from 4 h of HDR prior to exercise.

Background: Working within the military as a ground combat solider is very physically demanding. Soldiers are required to handle situations ranging from peacekeeping to counterinsurgency and combat, while faced with the task of load carriage either in form of the military gear or other additional loads. Therefore, a good aerobic and anaerobic fitness is necessary. The aerobic and anaerobic fitness can be assessed with a wide range is methods such as measuring the peak oxygen uptake (VO2peak), ventilator threshold, blood lactate concentration and heart rate. However research is rather spares regarding the effects of load carriage on the aerobic capacity. Aim: The aim of the current study was to investigate if military gear affects VO2peak, ventilatory threshold, blood lactate concentration and heart rate in ground combat soldiers. Methods: A total of eight soldiers (seven men and one woman) participated in the current study. All participants completed two biological calibrations and VO2max tests (one without and one with military gear) using a modified Bruce protocol, where VO2 (L/min), absolute and relative VO2peck (L/min and ml/kg/min respectively), heart rate (beats/min) and blood lactate concentration (mM/L) were assessed. After the completion of the tests, the soldier’s individual ventilatory threshold (VT) was visually located using the V-slope method. The Wilcoxon test was used for the not normally distributed variables (blood lactate concentration and stage when VT occurred) and the paired sample t-test for the others. The significance level was set to 0.05. Results: The results showed that the soldier had 10.6 % lower absolute VO2peak and 23.7 % lower relative VO2peak while wearing military gear compared to without (p=0.002 and p=0.001 respectively). The soldiers also had 11.8 % higher VO2 at VT with military gear (p=0.003) and reached a higher percentage of the VO2peak (p=0.023) at VT. The blood lactate concentration was significantly higher when marching at 5.4 km/h and a trend of a higher blood lactate concentration while standing was observed without military gear compared to with military gear. Conclusion: The findings from the present study shows that performing load carriage in form of the military gear significantly decreased the VO2peak. Wearing a military gear also increased the VO2 at the individual VT and made the soldier reach a higher percentage of the VO2peak at VT. These results can act as guidance when recruiting and training soldiers, along with providing important information to other professions and sports that involve load carriage.

Heart failure is a term for a group of complex symtoms characterized by reduced heart function. One of these syndromes, referred to as heart failure with preserved ejection fraction (HFpEF), has increased in prevalence compared to other types of heart failures during the recent years. A concern is the difficulty in diagnosing patients with HFpEF, since current tools are considered insufficient. The aim of this thesis was to examine Peak Oxygen Uptake (VO2peak) in relation to Total Heart Volume (THV) among heart failure patients with preserved ejection fraction (HFpEF, EF &gt;40 %) compared to healthy controls. THV was acquired by delineating images acquired using cardiovascular magnetic resonance imaging, while VO2peak was measured in oxygen curves acquired from cardiopulmonary exercise tests. Ratios were calculated by dividing VO2peak with THV. In order to determine if blood hemoglobin concentration (b-Hb) could affect the ratio, ratios were adjusted to b-Hb using an adjusting factor. Mean THV was nearly 250 ml larger in HFpEF patients compared to the controls. Patients’ mean VO2peak was more than 1000 ml lower compared to the controls. Mean VO2peak/THV ratio calculated for the patients were less than half of that calculated for the controls. Adjusting the ratio to b-Hb did not affect the ratios significantly. The study was limited by the size of the test group, but the findings suggest that a VO2peak/THV ratio can be used to separate HFpEF patients from healthy controls. / Hjärtsvikt är ett begrepp för en grupp med komplexa symtom och kännetecknas av försämrad hjärtfunktion. Ett av dessa syndrom, hjärtsvikt med bevarad ejektionsfraktion (HFpEF), har ökat i prevalens jämfört med andra varianter av hjärtsvikt under de senaste åren. Ett problem är de svårigheter som finns med att diagnosticera patienter med HFpEF, då nuvarande verktyg inte är tillräckliga. Syftet med detta examensarbete var att undersöka maximalt syreupptag (VO2peak) i förhållande till total hjärtvolym (THV) bland hjärtsviktspatienter med bevarad ejektionsfraktion (HFpEF, EF &gt;40 %) jämfört med friska kontroller. THV erhölls genom att utlinjera bilder tagna med hjälp av magnetisk resonanstomografi, medan VO2peak mättes i syrevolymkurvor som registrerats under ergospirometri-undersökningar. Index beräknades genom att dividera VO2peak med THV. För att undersöka huruvida halten hemoglobin i blodet (b-Hb) kunde påverka index justerades index mot b-Hb med hjälp av en justeringsfaktor. Medel-THV var nästan 250 ml större hos HFpEF-patienter jämfört med kontroller. Medel-VO2peak var mer än 1000 ml lägre hos patienterna jämfört med kontroller. Medel VO2peak/THV-index som beräknats för patienter var mindre än hälften så högt som index beräknat för kontroller. Att justera index mot b-Hb påverkade inte index signifikant. Studien begränsades av mängden deltagare, men fynden indikerar att VO2peak/THV-index kan användas för att skilja HFpEF-patienter från friska kontroller.