In light of the current global prevalence of overweight and obesity, the associated health risks, and the continuing adoption of sedentary lifestyle, this thesis investigated some of the factors that contribute to exercise adherence, directly comparing high-intensity whole body interval training and continuous endurance training. 68 inactive university aged adults (Age: 21.4±3.4 yrs, BMI: 25.6±4.6 kg/m2, VO2peak 40.1±5.7 ml/kg/min) were randomized into one of three groups; a non-exercise control, whole body high intensity training, or continuous endurance training. Aerobic capacity measurements, time to completion trials, muscular endurance, and core strength measures were taken at pre, post and follow up testing sessions. Psychological questionnaires were also administered during exercise as well as throughout the study. Following the intervention both exercise groups demonstrated equivalent improvements in aerobic performance, with only the interval group experiencing improved muscular and core endurance. After the 2-month follow up testing sessions the interval group lost all aerobic and core adaptation, with endurance only experiencing a partial loss. This finding indicates that the interval group did not adhere to exercise at a level that was high enough to preserve the adaptations associated with training. This finding is further supported by the psychological factors measured throughout this study, including acute affect, enjoyment and intentions to engage in future exercise. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2013-10-31 15:08:15.524

Master of Science / Department of Kinesiology / Craig A. Harms / High-intensity interval training (HIT) has been utilized as a time-efficient strategy to induce numerous physiological adaptations and improve performance usually associated with “traditional” endurance training (ET). It is not known however, if HIT might lead to improvements in pulmonary function. Therefore we hypothesized that HIT would increase respiratory muscle strength and expiratory flow rates. Fifteen healthy subjects were randomly assigned to an ET group (n = 7) and a HIT group (n = 8). All subjects performed an incremental test to exhaustion (VO2 max) on a cycle ergometer prior to and after training. Standard pulmonary function tests, maximum inspiratory pressure (PImax), maximum expiratory pressure (PEmax), and maximal flow volume loops, were performed pre training and after each week of training. HIT subjects performed a four week training program on a cycle ergometer at 90% of their VO2 max final workload while the ET subjects performed exercise at 60-70% of their VO2 max final workload. All subjects trained three days/ week. The HIT group performed five one-minute bouts with three minute recovery periods and the ET group cycled for 45 minutes continuously at a constant workload. A five-mile time trial was performed prior to training, after two weeks of training, and after four weeks of training. Both groups showed similar (p<0.05) increases in VO2 max (~8-10%) and improvements in time trials following training (HIT 6.5 ± 1.3%, ET 4.4 ± 1.8%) with no difference (p>0.05) between groups. Both groups increased (p<0.05) PImax post training (ET ~25%, HIT ~43%) with values significantly higher for HIT than ET. There was no change (p>0.05) in expiratory flow rates with training in either group. These data suggest that whole body exercise training is effective in increasing inspiratory muscle strength with HIT leading to greater improvements than ET. Also, HIT offers a time-efficient alternative to ET in improving aerobic capacity and performance.

Master of Science / Department of Kinesiology / Craig A. Harms / Subjects with prehypertension are at risk for developing hypertension (HTN). Hypertension is associated with low-grade systemic inflammation (LGSI). Aerobic exercise training (ET) is a proven means to reduce both blood pressure and LGSI in healthy and diseased subjects. Recently, high intensity interval training (HIIT) has been show to elicit similar cardiovascular and metabolic adaptations as ET in healthy and at-risk populations in a more time efficient manner. Therefore, we hypothesized that HIIT would elicit greater reductions in blood pressure and LGSI than ET. Twelve pre-hypertensive subjects (systolic blood pressure 127.0 ± 8.5 mmHg; diastolic blood pressure 86.2 ± 4.1 mmHg) were randomly assigned to an ET group (n=5) and a HIIT group (n=7). All subjects performed an incremental test to exhaustion (VO2max) on a cycle ergometer prior to, after 4 weeks, and after 8 weeks of training. Resting heart rate and blood pressure were measured prior to and three times a week during training. LGSI was measured via high-sensitivity C-reactive protein (hs-CRP) prior to, after 4 weeks and after 8 weeks of training. ET subjects performed an eight week exercise training program at 40% VO2 reserve determined from the VO2max test, while HIIT subjects performed exercise at 60% peak power determined from the VO2max test. ET group trained four days/week while HIIT trained three days/week. ET exercised for 30 minutes continuously at a constant workload and cadence of 60 rpm while HIIT performed a protocol on a 1:1 work-to-rest ratio at a constant workload and cadence of 100 rpm. Both groups showed similar (p<0.05) decreases in mean arterial (ET = -7.3%, HIIT = -4.5%), systolic (ET = -6.6%, HIIT = -8.8%), and diastolic (ET= -9.7, HIIT= -8.2%) blood pressure. HIIT decreased in LGSI (-33.7%) while ET did not change LGSI (p>0.05). VO2max increased ~25% with both HIIT and ET with no differences (p>0.05) between groups. These data suggest both HIIT and ET similarly decreased resting blood pressure and increased VO2max while HIIT was effective in decreasing LGSI in subjects who were pre-hypertensive.

Although there is an abundance of research investigating the effects of exercise on cognitive function, few studies have investigated acute effects of exercise on performance of tasks involving executive function. Furthermore, the effects of different exercise intensities on multiple tests of executive function have received little attention. The purpose of this study was to examine the acute effects of 20-minutes of stationary cycling exercise at varying exercise intensities on executive function performance and to determine these acute effects immediately following exercise as well as after 10 and 30-minute delays following exercise. University students (N = 88) completed baseline measures of executive function (stop-signal task [SST] and Stroop task [ST]) and a graded cardiovascular exercise test on Visit 1. On Visit 2, participants were stratified by gender and fitness level and randomized to one of four conditions: high-intensity interval training (HIT), high, moderate or low-intensity steady-state exercise performed on a cycle ergometer. The ST and SST were performed immediately following exercise and again at 10- and 30-minutes post-exercise. Immediately following exercise, ST response times were significantly different (p < .05), demonstrating faster response times for the high and moderate intensity exercise (p < .05), while improvements in SST response inhibition were revealed for the HIT (p < .01) condition. At 10-minutes post-exercise, moderate and low-intensity conditions revealed improvements in ST response times (p <.05), with enhanced SST response inhibition evident in the HIT, moderate and low-intensity conditions (p < .05). At 30-minutes post-exercise, ST response times continued to show improvements from baseline for the moderate and low-intensity conditions (p < .05), while SST response inhibition trended back towards baseline levels (p > .05). The present outcomes demonstrate beneficial effects of exercise, regardless of intensity, for up to 38 minutes post-exercise. Future research should focus on mechanisms that would account for these effects and factors that support enhanced executive function performance with exercise training. / Thesis / Master of Science (MSc)

Whilst high levels of cardiorespiratory fitness and physical activity may protect against cardiometabolic risk factor clustering, evidence suggests these outcomes are below optimal in English youths. Adolescence is a key stage in health behaviours development, and thus represents an opportunity for interventions aiming to improve the cardiometabolic health, fitness and activity levels of this population. Recently, there has been growing interest in the efficacy of low-volume high-intensity interval training (HIT) as a time efficient way of improving health and fitness outcomes in adults. Contrastingly, the effects of low-volume HIT in adolescents remains relatively unknown. The first aim of this programme therefore was to develop a novel school-based low-volume HIT intervention. The second was to determine the effectiveness of this model for improving the cardiometabolic health, cardiorespiratory fitness and physical activity levels of adolescents. Study one examined adolescents’ views towards high-intensity exercise, and the proposed low-volume HIT intervention. This data was used to design the novel low-volume HIT model. In Study 2, participants’ heart rate and perceived exertion responses to three prototype prescriptions of low-volume HIT, based on boxing, dance and football were examined. Here, it was indicated that these activities were capable of eliciting a high-intensity training response (~90% of maximum heart rate). Study 3 incorporated the main intervention, which examined the effect of a 10-week multi-activity low-volume HIT intervention (named Project FFAB [Fun Fast Activity Blasts]) on various health and fitness outcomes in adolescents. Here, beneficial effects were detected in the intervention participants compared to the controls for triglycerides, waist circumference, lipid accumulation product and daily moderate-to-vigorous physical activity. Study 4 assessed the fidelity of the intervention, and found that this had been largely upheld. Collectively therefore, it appears that Project FFAB represents a viable strategy for improving aspects of cardiometabolic health and physical activity levels in adolescents.

A síndrome metabólica (SM) é uma somatória de fatores de risco para desenvolvimento de doenças cardiovasculares (DCV), intimamente ligada à obesidade e, assim como a última, sua prevalência cresce mundialmente. Sua etiologia é complexa e suas causas são influenciadas por fatores ambientais e genéticos. Sabe-se que a elevação da capacidade cardiorrespiratória (VO2máx) seja um melhor atenuador do risco de mortalidade por DCV do que a própria obesidade. Atualmente a forma conhecida para aumento do VO2máx é o exercício físico aeróbio, porém vários indivíduos reportam falta de tempo para realização de uma rotina de exercícios físicos. Neste contexto, o presente trabalho teve como objetivo comparar dois protocolos de treinamento aeróbio de alta intensidade e outro contínuo de moderada intensidade quanto à influência na capacidade cardiorrespiratória, variáveis de síndrome metabólica (circunferência da cintura - CC, glicemia de jejum, HDL, triglicérides e pressão arterial) e composição corporal (massa e percentual de gordura) em indivíduos com sobrepeso/obesidade e; observar a influência de polimorfismos dos genes visfatina e receptor tipo 1 de angiotensina 2 (AGTR1) nos níveis de glicemia, HDL, triglicérides e pressão arterial. 40 indivíduos foram divididos aleatoriamente em três grupos de treinamento: contínuo moderado (CM), 4x1 e 4x4. O grupo CM realizou cinco sessões semanais de treino por 30 minutos; os grupos 4x1 e 4x4 realizaram 3 sessões semanais com duração de 19 e 40 minutos, respectivamente. A intervenção durou 16 semanas e as sessões foram monitoradas quanto à frequência cardíaca para controlar a intensidade do exercício. O grupo CM se exercitou a 70% da frequência cardíaca máxima, enquanto os grupos 4x1 e 4x4 realizaram estímulos a 90% da frequência cardíaca máxima. Os resultados encontrados apontaram uma melhora na capacidade cardiorrespiratória em todos os grupos, sem diferença entre eles. Diminuição da massa corpórea, IMC, percentual de gordura somente no grupo 4x4. Diminuição de CC nos grupos 4x4 e CM. Os dados da análise genética não apontaram nenhuma relação entre os polimorfismos avaliados e as variáveis de interesse. Por fim, concluiu-se que o treinamento de alta intensidade com duração de 19 minutos promove resultados semelhantes ao treinamento de mesma intensidade e duração de 40 minutos e ao treinamento de intensidade moderada na capacidade cardiorrespiratória em indivíduos com sobrepeso/obesidade, sendo uma alternativa viável para treinamento físico com pouco volume. / Metabolic syndrome (MS) is a sum of risk factors for developing cardiovascular disease (CVD), closely linked to obesity and, like the latter, its prevalence is growing worldwide. Its etiology is complex and its causes are influenced by environmental and genetic factors. It is known that the increase in cardiorespiratory fitness (VO2max) is a better attenuator of CVD mortality risk rather than obesity itself. Currently, the best known way to increase VO2max is aerobic exercise, but many people report lack of time to perform a exercise routine exercise. In this context, this study aimed to compare two high intensity aerobic exercise protocols and a continuous moderate exercise regarding their effects on cardiorespiratory fitness, metabolic syndrome variables (waist circumference - WC, fasting plasma glucose, HDL, triglycerides, and blood pressure) and body composition (body mass and fat percentage) in overweight/obese individuals and; observe the influence of genetic polymorphisms of visfatin and angiotensin 2 receptor type 1(AGTR1) in blood glucose levels, HDL, triglycerides and blood pressure. 40 subjects were randomly divided into three training groups: continuous moderate intensity (CM), 4x1 and 4x4. The CM group held five weekly training sessions for 30 minutes; the 4x1 and 4x4 groups performed three weekly sessions lasting 19 and 40 minutes, respectively. The intervention lasted 16 weeks and the sessions were monitored for heart rate to control the exercise intensity. The CM group exercised at 70% of maximum heart rate, while the 4x1 and 4x4 groups performed stimuli to 90% of maximum heart rate. The findings showed an improvement in cardiorespiratory fitness in all groups, with no difference between them. A decreased body mass, BMI, body fat percentage only in the group 4x4. WC decrease in 4x4 and CM groups. Data from genetic analysis did not show any relationship between the evaluated polymorphisms and the variables of interest. Finally, it was concluded that the high intensity training lasting 19 minutes promotes similar results to the training of the same intensity and duration of 40 minutes and moderate intensity training on cardiorespiratory fitness in overweight/obese individuals, being a viable alternative for exercise training with low volume.

O objetivo do presente estudo foi verificar os efeitos do treinamento intervalado de alta intensidade (TIAI), específico e não específico, sobre respostas fisiológicas e desempenho em testes aeróbios e anaeróbios, bem como sobre ações técnicas e táticas durante a luta de judô. 35 atletas de judô realizaram uma série de testes antes e após quatro semanas de treinamento, sendo aleatoriamente divididos em quatro grupos: TIAI para membros inferiores, TIAI para membros superiores, TIAI específico [por meio de entrada de golpes (uchi-komi)] e grupo controle. Os grupos experimentais treinaram o exercício intervalado de alta intensidade (EIAI) adicionalmente ao treino de judô e o grupo controle realizou apenas judô. Foi utilizado o mesmo tipo de estímulo em regiões corporais distintas: realização de duas sessões semanais de EIAI constituídas por dois blocos de 10 estímulos de 20s por 10s de intervalo entre os estímulos e 5 min entre os blocos, i.e., grupo de membros superiores e inferiores utilizaram cicloergômetros específicos para cada região corporal, enquanto o grupo específico desempenhou uchi-komi em intensidade all-out com atleta de massa corporal similar. Os grupos e momentos foram comparados via análise de variância (ANOVA) a dois fatores (grupo e momento do treinamento) ou a três fatores (grupo, momento do treinamento e momento da medida), seguida pelo teste de Bonferroni. Quando encontrada diferença entre os grupos durante as semanas de treinamento, foi efetuada uma ANOVA a um fator com medidas repetidas, bem como o teste-t pareado para os valores pré e pós-treinamento. Os principais resultados apontam que: para o grupo de membros inferiores houve aumento da potência equivalente ao onset blood lactate accumulation (OBLA) no teste progressivo para membros superiores, aumento da potência média no teste de Wingate adaptado para membros inferiores, redução da frequência cardíaca após o Special Judo Fitness Test (SJFT), redução do número de sequências em pé durante a simulação de luta e aumento da razão testosterona/cortisol (T/C) pós-simulação de luta no momento pós-treinamento; para o grupo de membros superiores, houve elevação da potência aeróbia máxima no teste progressivo máximo para membros superiores, aumento do número total de projeções no SJFT, redução das concentrações de CK e elevação da razão T/C pós-simulação de luta no pós-treinamento, bem como elevação das concentrações de LDH nas mensurações conduzidas em repouso; para o grupo uchi-komi, houve aumento da potência pico no teste de Wingate para membros superiores e inferiores, redução do índice no SJFT e aumento da razão T/C pós-simulação de luta no momento pós-treinamento. Não foram detectadas alterações no desempenho para o grupo controle pós-treinamento. Além disso, não foram detectadas quaisquer alterações para as respostas psicométricas, hormonais, assim como para o sistema nervoso autônomo após as quatro semanas de intervenção. Os resultados indicam que a adição do TIAI à rotina de treinamento usual de judô eleva a potência aeróbia máxima para membros superiores e desempenho intermitente de alta intensidade para membros superiores e inferiores em testes genéricos. Adicionalmente, o TIAI melhora aspectos relevantes para o desempenho em tarefas específicas do judô. Por fim, o TIAI de baixo volume não promoveu alterações nas respostas do sistema nervoso autônomo, questionários psicométricos e respostas hormonais ao longo das quatro semanas de treinamento / The aim of the present study was to verify the effects, specific and non-specific, of high intensity interval training (HIIT) on physiological and performance responses to aerobic and anaerobic tests, as well as on technical and tactical actions during judo combat. In order to achieve this purpose, 35 judo athletes were randomly selected into four groups: HIIT for lower-body, upper-body, specific group (by means of technique-entrance, uchi-komi) and a control group. These groups completed a series of tests, before and after a 4-week training period. The experimental groups did high intensity interval exercise (HIIE) in addition to judo training while the control group did judo training only. The same type of stimulus was used on distinct body regions: two weekly sessions of HIIE consisting of two blocks of 10 x 20s stimuli with a 10s interval between stimuli and a 5-min interval between blocks, i.e., the lower and upper-body group used cycle-ergometer for each body region, while the specific group carried out uchi-komi at all-out intensity with another athlete of similar body mass and stature. The groups and moments were compared via variance analysis (ANOVA) to two factors (group and training) or to three factors (group, training and time of measurement), followed by the Bonferroni test. When a difference was detected between groups during the training weeks, a one-way (ANOVA) was carried out with repeated measures, as well as the paired t-test, for pre and post-training values. The main results indicate that: The lower-body group showed increase in the equivalent power to onset blood lactate accumulation (OBLA), in aerobic fitness test for upper- limbs, increase in the mean power in the Wingate test (4 sets of 30s interspersed with 3-min recovery period) for lower limbs, heart rate reduction after the Special Judo Fitness Test (SJFT), reducing the number of standing sequences during the match simulation and increasing the testosterone/cortisol ratio (T/C) after the match simulation in the post-training period; For the upper-body group, showed an increase of the maximum aerobic power in aerobic fitness test for upper limbs, increase in the total number of projections in SJFT, reduced CK concentrations (post-training period), increase in T/C ratio post-match in the post-training period and increase in LDH concentrations in measurements conducted at rest. Uchi-komi group, showed an increased in the peak power in the Wingate test for upper and lower limbs, reduction of the SJFT index and increasing the T/C ratio after the match-simulations in the post-training period. As expected, were not found any performance changes after 4-weeks of intervention for the control group Furthermore, were not detected any changes to the psychometric, hormonal responses, as well as the autonomic nervous system after four weeks of intervention for all experimental groups. Therefore, these findings suggest that addition of the HIIT to usual judo training increases the maximum aerobic power for upper limbs and high-intensity intermittent performance for upper and lower limbs, in generic tests. Moreover, HIIT improves relevant aspects to performance in specific judo tasks. Finally, low volume HIIE did not bring about any alterations to the autonomous nervous system responses, psychometric responses or hormonal responses throughout the four weeks of training

Despite clear recommendations on the minimal amount of physical activity for achieving health benefits and reducing risk of chronic disease, the majority of people in the Western world remain sedentary. As a 'lack of time' has been identified as one of the main barriers to becoming and remaining physically active, in the past decade research has focused on high-intensity interval training (HIT) as a time-efficient alternative to aerobic exercise. Although initial studies convincingly demonstrated equal or better health benefits with various HIT protocols compared to much larger volumes of aerobic exercise, these HIT protocols tend to be very strenuous and as such are unlikely to be adhered to by sedentary populations. Furthermore, most HIT protocols are not as time-efficient as sometimes claimed, with the total time per exercise session generally exceeding 20-30 minutes. This thesis aimed to characterise the effects of a novel reduced-exertion HIT (ReHIT) protocol, requiring a maximum of 2 x 20 s all-out sprint efforts in a 10 min training session, upon insulin sensitivity, aerobic capacity, glycogen utilisation and associated acute metabolic responses. The ReHIT exercise bouts were well tolerated by participants, but were associated with a substantial disturbance of physiological homeostasis including muscle glycogen degradation, lactate accumulation, excursions in plasma volume, post-exercise oxygen consumption, respiratory exchange ratio and heart rate, as well as a skeletal muscle signalling response through AMPK, and increases in skeletal muscle GLUT4 and PGC1α mRNA expression (Chapter 4 and 5). The combined training studies (n=49) provide some support for improvements in key disease biomarkers following ReHIT, with improvements in insulin sensitivity observed in men, and increased aerobic capacity observed in men and women (Chapter 7). These observations highlight a potential regulatory role for glycogen in exercise-induced adaptation. However, the mean improvements in insulin sensitivity in men were not consistent between the two training studies (Chapter 2 and 6), and there was a high level of variability observed between individuals (Chapter 6 and 7). Therefore, the impact of ReHIT on insulin sensitivity needs to be further explored in the context of a randomised controlled trial, and the mechanisms underpinning the large variability in adaptive response need to be characterised.

This study examined the effects of short-term high-intensity interval training (HIT) and continuous moderate-intensity training (CMT) on left ventricular (LV) function in young, healthy men. Sixteen untrained men were randomly assigned to HIT (8-12 X 60:75 seconds cycling at 95-100%:10% V˙O2peak) and CMT (90-120 minutes cycling at 65% V˙O2peak) and assessed before and after six sessions of training. LV function was determined at rest and during submaximal exercise using two-dimensional and Doppler echocardiography. HIT and CMT improved V˙O2peak and induced plasma volume expansion to a similar magnitude. Although resting LV function did not change, increased exercise stroke volume and cardiac output was observed, secondary to increases in end-diastolic volume. Numerous ECHO-derived indices of diastolic performance were similarly enhanced during exercise in both groups. Short-term HIT and CMT elicit rapid increases in V˙O2peak and LV filling without global changes in systolic performance or cardiac morphology at rest.

This study examined the effects of short-term high-intensity interval training (HIT) and continuous moderate-intensity training (CMT) on left ventricular (LV) function in young, healthy men. Sixteen untrained men were randomly assigned to HIT (8-12 X 60:75 seconds cycling at 95-100%:10% V˙O2peak) and CMT (90-120 minutes cycling at 65% V˙O2peak) and assessed before and after six sessions of training. LV function was determined at rest and during submaximal exercise using two-dimensional and Doppler echocardiography. HIT and CMT improved V˙O2peak and induced plasma volume expansion to a similar magnitude. Although resting LV function did not change, increased exercise stroke volume and cardiac output was observed, secondary to increases in end-diastolic volume. Numerous ECHO-derived indices of diastolic performance were similarly enhanced during exercise in both groups. Short-term HIT and CMT elicit rapid increases in V˙O2peak and LV filling without global changes in systolic performance or cardiac morphology at rest.