<p>Research in this thesis has focused on development and application of novel methodologies that enhance sample throughput and data fidelity when performing untargeted metabolome profiling by multisegment injection-capillary electrophoresis-mass spectrometry (MSI-CE-MS). Metabolomics is a valuable tool in functional genomics research to investigate underlying molecular mechanisms associated with human health since metabolites are “real-world” end-products of gene expression. CE-MS is well-suited for metabolomics because it is a high efficiency microseparation technique that can be used to resolve complex mixtures of polar metabolites in human biofluids without complicated sample workup. In this thesis, a novel CE-MS assay for estrogens and their intact ionic conjugates has been described (<em>Chapter II</em>) to expand metabolome coverage that enables resolution of positional isomers with high selectivity. This is critical for better understanding of underlying perturbations in estrogen metabolism since the biological activity of estrogens are dependent on specific primary and secondary metabolic transformations. MSI-CE-MS has been introduced as a high-throughput approach for large-scale metabolomic studies based on serial injection of multiple segments of sample within a single fused-silica capillary (<em>Chapter III</em>). It reduces analysis times while increasing data quality and confidence in peak assignment together with better quality assurance. An accelerated workflow for metabolomics has also been developed when using MSI-CE-MS, where a dilution trend filter is used as a primary screen to authenticate reproducible sample-derived metabolites from a pooled sample while eliminating spurious artifact and background signals. In this way, complicated time alignment and peak picking algorithms are avoided when processing data in metabolomics to reduce false discoveries. This strategy was subsequently used in two metabolomics applications (<em>Chapters IV</em> and <em>V</em>) to identify plasma markers associated with strenuous exercise and adaptive training responses following a six-week high intensity interval training. The impact of exercise intervention to improve the glucose tolerance of a cohort of overweight/obese yet non-diabetic women was investigated on an individual level when using a cross-over design. Personalized interventions are critical in designing more effective therapies to prevent metabolic diseases due to inter-subject variations in treatment responses, including potential adverse effects. MSI-CE-MS offers a revolutionary approach for biomarker discovery in metabolomics with high sample throughput and high data fidelity, which is critical for validation of safe yet effective lifestyle interventions that promote human health and reduce risk for chronic diseases.</p> / Doctor of Philosophy (PhD)

<p> Increased arterial stiffness and vascular endothelial dysfunction have been identified as independent risk factors for the development and progression of cardiovascular disease. Traditional endurance training has been associated with elevated levels of central arterial compliance and an attenuation of cardiovascular events. As well, the positive benefits of aerobic-based training have been acknowledged as effective modulators of vascular endothelial function. To date, the impact of sprint interval training on cardiovascular health has not been evaluated. Furthermore, the mechanisms responsible for previously observed enhancements in endurance (750 kJ) performance following two weeks of sprint interval training remain unclear, but may be related to changes in vascular structure and function.</p> <p> Nine young healthy males [age: 22 ± 0.5 (mean± SEM)] participated in a two week sprint interval training program consisting of 4-6 30 second maximum effort exercise bouts performed every other day on a cycle ergometer. In addition, each participant was required to complete a 750 kJ time trial on a cycle ergometer as a measure of aerobic exercise performance before (PRE) and after (POST) training. Measurements of supine, resting carotid pulse pressure, carotid cross-sectional compliance, and brachial vascular endothelial function (using flow mediated dilation) were also acquired PRE and POST training.</p> <p> Resting pulse pressure did not show any significant changes with exercise training (PRE= 48.6±1.6, POST= 52.4±2.5 mmHg, p>0.05). Mean brachial artery diameter was not changed with sprint interval training (PRE= 4.29±0.17, POST= 4.38±0.18 mm, p>0.05); however, mean carotid artery diameter increased significantly PRE to POST (PRE= 6.40±0.15, POST= 6.49±0.14 mm, p=0.008). Carotid cross-sectional compliance did not change PRE to POST training (PRE= 0.164±0.010, POST= 0.162±0.007 mm^2/mmHg, p>0.05). Brachial vascular endothelial function measured using flow-mediated dilation did not show a significant change with sprint interval training, however a trend towards improvement was noted (PRE= 4.6±1.8, POST= 6.4±1.0 %, p=0.296). When normalized for shear rate (which was also unaltered with sprint interval training) there were no changes in endothelial function (PRE = 0.158±0.068, POST= 0.198 ± 0.034 %/S^-1, p>0.05). Average brachial post-occlusion blood flow was significantly enhanced following training possibly revealing enhanced resistance vessel function (PRE= 296.0±37.4, POST= 324.8±38.8 ml/min, p=0.04), despite no change in peak brachial blood flow (PRE= 332.0±42.3, POST= 362.6±45.7 ml/min, p>0.05). 750 kJ time trial performance was significantly enhanced with training (PRE = 62.8±4.9; POST= 55.84±3.55 min; p=0.006).</p> <p> In conclusion, sprint interval training did not change resting carotid compliance or brachial endothelial function, despite significant improvements in aerobic performance (750 kJ). However, carotid resting diameters and brachial post occlusion blood flow were significantly increased PRE to POST and a trend towards improvement was seen for brachial flow mediated dilation. The exact mechanisms responsible for such changes remain unknown and require further investigation.</p> / Thesis / Master of Science (MSc)

Endothelium-dependent vasodilation is an important marker of vascular function. Brachial artery flow-mediated dilation (FMD) is a noninvasive assessment of peripheral artery endothelial function that is associated with coronary artery endothelial function and is an index of cardiovascular health. This thesis sought to investigate factors that may influence the brachial artery FMD response in humans, particularly the sex hormone estrogen and low-volume sprint interval training (SIT). We first demonstrated the intra-individual consistency of the FMD response pattern in healthy young adults and introduced visual data screening as a tool for improving data accuracy. Having established best practices for FMD data analysis, we investigated the brachial artery FMD response in adults with different estrogen profiles: men, premenopausal women with a natural menstrual cycle (NAT), and premenopausal women using combined oral contraceptive pills (OCP). Our findings suggest that estrogen does not augment FMD during high-estrogen phases of a NAT or OCP cycle compared to low-estrogen phases or to men. We also investigated the acute and chronic brachial artery FMD response to a 3x20-s low-volume SIT model. Following a single SIT session, FMD was unchanged in men or women. These findings demonstrate that estrogen does not influence endothelium-dependent dilation at rest or following intense intermittent exercise, but also suggest that low-volume SIT may be an insufficient stimulus for eliciting changes in endothelial function. This stimulus magnitude postulation was further supported by a 12-wk exercise training study, whereby vascular changes were evident following moderate-intensity continuous training but not SIT. Taken together, this work suggests that controlling for menstrual cycle phase and/or OCP use in premenopausal women may not be necessary, making it more feasible to include women as research participants, and highlights the need for future characterization of the minimum low-volume interval stimulus that evokes improvements in endothelial function in healthy young adults. / Thesis / Doctor of Philosophy (PhD) / The endothelium is the inner lining of an artery that separates it from the flowing blood. A healthy endothelium responds to increases in blood flow by producing substances that enable an artery to widen. The projects in this thesis examined whether the responsiveness, and overall function, of the endothelium in healthy young adults is enhanced by the sex hormone estrogen or by “all-out” cycling sprints, an exercise protocol that has gained appeal for its time-efficiency. We demonstrated that estrogen does not enhance endothelial function in women, compared to men, at any phase of a menstrual or birth control pill cycle. A single session or 12-weeks of the intense but brief interval exercise also does not enhance endothelial function. This work suggests it may be easier to include women in future research assessing this measure and that this particular interval exercise protocol may not enhance endothelial function in healthy adults.

During inpatient rehabilitation, arm-ergometry training is utilized to improve the physical capacity of patients with a sub-acute spinal cord injury (SCI) to a level that is desirable for performing activities of daily living (ADLs). Previous work has demonstrated that ≥ 20 minutes of moderate-intensity continuous training (MICT) during inpatient rehabilitation, at a frequency of ≥ 3 times per week, is useful for increasing the physical capacity of these patients. However, considering that inpatient rehabilitation is an intensive program, and given the trend towards a shortened length of stay during inpatient rehabilitation, performing MICT on the arm-ergometer can consume a valuable amount of therapy time. Low-volume sprint interval training (SIT) is a time-efficient alternative to MICT for improving indices of physical fitness in healthy and diseased populations. To date, however, there are no published studies comparing SIT to MICT in persons with sub-acute SCI undergoing inpatient rehabilitation.The purpose of this thesis was to evaluate the efficacy of a five-week, thrice weekly low-volume SIT protocol on the arm-ergometer and compare fitness outcomes to traditional MICT in patients with sub-acute SCI undergoing inpatient rehabilitation. Participants with sub-acute SCI undergoing inpatient rehabilitation were recruited and randomly allocated to the SIT or MICT training group. Both types of training utilized the same 2 min. warm-up and 3 min. cool-down. SIT consisted of 3 x 20 sec. “all-out” cycle sprints (≥ 100% of peak power output [POpeak]), interspersed with 2 min. of low activerecovery (≈ 10% of POpeak; total time commitment, 10 mins). MICT involved 20 min. of arm cycling (45 – 60% of POpeak; total time commitment, 25 mins). SIT elicited a higher relativheart rate response, and ratings of perceived exertion than MICT. Following training, we found similar improvements in maximal and sub-maximal physical capacity across groups. Both exercise modes were equally well tolerated, and enjoyable, and there were no differences in self-efficacy across groups. The significance of this work is that it is the first randomized-controlled trial comparing SIT to MICT on the arm-ergometer in individuals with sub-acute SCI undergoing inpatient rehabilitation. The fact that SIT is palatable and can promote similar increases in physical capacity as MICT, despite less than half the time commitment and training volume, means that clinical rehabilitation specialists can now offer a new, more time-efficient, exercise training strategy to elicit improvements in their patients. / Thesis / Master of Science (MSc)

This thesis is missing page 63 from all copies. -Digitization Centre / Manipulating carbohydrate (CHO) availability has been shown to alter acute exercise-induced changes in metabolic gene transcription and training-induced changes in oxidative capacity. The present study examined the effect of CHO availability on signalling pathways linked to mitochondrial biogenesis in response to high-intensity interval exercise (HIE). We hypothesized that reduced CHO availability would augment phosphorylation of AMP-activated protein kinase (AMPK), calcium/calmodulin-dependent kinase II (CaMKII), and p38 mitogen-activated protein kinase (p38) in response to HIE. Ten active men performed two experimental trials in random order, separated by 2:1 wk. During each trial, subjects performed two HIE sessions separated by 3 h (AM and PM sessions). Exercise sessions consisted of 5 x 4 min cycling bouts at a workload that elicited approximately 90% V02peak, with 2 min rest periods. Between sessions, subjects ingested -1.2 g CHO/kg b.w./h (HI-HI) or a taste-matched, non-energetic placebo (HI-LO). Muscle biopsies and blood samples were obtained before (Pre) and after (Post) the AM and PM HIE sessions. AMPK, CaMKII, and p38 MAPK phosphorylation increased from AM Pre to AM Post (p<0.01). During the PM exercise session, p38 phosphorylation increased in the HI-LO condition (-4.5-fold, p<0.001), whereas the HI-HI condition remained unchanged. PM HIE significantly increased CaMKII phosphorylation independent of condition, while no exercise or condition-mediated AMPK effects were observed. In summary, restricting CHO availability following an acute session of HIE augmented the exercise-induced increase in p38 phosphorylation during a subsequent HIE session. It remains to be determined whether chronic changes in p38 MAPK signalling are mechanistically linked to altered skeletal muscle remodelling observed after CHO-restricted exercise training. / Thesis / Master of Science (MS)

Background: Axial Spondyloarthritis (axSpA) is an autoimmune, chronic, rheumatic and inflammatory disease. In axSpA, the sacroiliac joint and the spine are affected, and common symptoms are stiffness and pain. For axSpA patients, systemic inflammation is a contributing factor to an increased risk of cardiovascular diseases (CVD). Calprotectin is a protein with multiple functions involved in the inflammatory response, and axSpA patients' calprotectin levels are elevated due to inflammation. Exercise is a non-pharmacological treatment, and for axSpA patients, it can reduce pain and increase mobility. The effects of High-intensity Interval Training (HIIT) have yet to be extensively researched in this patient group. Performing HIIT can increase maximal oxygen uptake (VO2max), reducing the risk of CVD. HIIT may also reduce inflammation, an essential factor in reducing the risk of CVD. Aim: The aim is to investigate how HIIT can affect calprotectin serum levels in axSpA patients and how calprotectin serum levels differ between healthy controls and axSpA patients. Method: Serum was collected before and after a HIIT bout from a cross-sectional pilot study, including axSpA patients (n=10) and healthy age- and sex-matched controls (n=11) and at baseline and after three months from a randomised control trial (RCT), which consisted of axSpA patients. The patients in the RCT were split into two groups: a control group (n=14) performing regular exercise and an intervention group (n=15) performing three HIIT sessions per week. Calprotectin in patients and healthy controls serum was analysed with a sandwich ELISA. Results: The comparison of serum calprotectin before and after a HIIT bout decreases in healthy controls (p=0.013) and indicates an increase of calprotectin in axSpA patients (p=0.059). After three months, the mean value of serum calprotectin in axSpA patients indicates a decrease in both the control and HIIT intervention groups. Conclusion: Our results suggest a trend towards regular HIIT, which can decrease serum calprotectin levels after three months. Therefore, HIIT could be considered a non-pharmacological treatment for axSpA patients. More studies with a larger axSpA population are necessary to investigate whether HIIT impacts serum calprotectin. / Bakgrund: Axial spondylartrit (axSpA) är en autoimmun, kronisk, reumatisk och inflammatorisk sjukdom. I axSpA påverkas sacroiliacaleden och ryggraden och vanliga symtom är stelhet och smärta. Patienter med axSpA har systemisk inflammation som är en bidragande faktor till ökad risk för hjärt-kärlsjukdomar (CVD). Kalprotektin är ett protein med flera funktioner som är involverat i den inflammatoriska responsen och hos patienter med axSpA är nivåerna av kalprotektin förhöjda på grund av inflammationen. Träning är en icke-farmakologisk behandling som kan minska smärta och öka rörlighet för axSpA patienter. Effekterna av högintensiv intervallträning (HIIT) har inte studerats i stor utsträckning i denna patientgrupp. Genom att utföra HIIT kan den maximala syreupptagningen (VO2max) förbättras, vilket kan minska risken för CVD. HIIT kan bidra till minskad inflammation, vilket kan minska risken för CVD. Syfte: Syftet är att undersöka hur HIIT kan påverka nivåerna av kalprotektin i serum hos patienter med axSpA och hur dessa nivåer skiljer sig mellan friska kontroller och patienter med axSpA. Metod: Serum har samlats in innan och efter ett HIIT pass från en tvärsnittsstudie och vid baseline och efter tre månader från en randomiserad kontrollstudie (RCT). Tvärsnittsstudien bestod av patienter med axSpA (n=10) samt friska ålders- och könsmatchade kontroller (n=11). RCTn bestod av patienter med axSpA som delades in i två grupper: en kontrollgrupp (n=14) som utförde regelbunden träning och en interventionsgrupp (n=15) som utförde tre HIIT-pass per vecka. Patienternas och de friska kontrollernas serum kalprotektin analyserades med en sandwich-ELISA. Resultat: Jämförandet av serum kalprotektin innan och efter ett HIIT pass hos friska kontroller visar en minskning av kalprotektin (p=0,013) och hos axSpA patienterna finns det en trend till en ökning av kalprotektin (p=0,059) efter HIIT-passet. Medelvärdet av serum kalprotektin hos axSpA patienter efter tre månader visar en tendens till en minskning i både kontroll- och HIIT-interventionsgruppen. Konklusion: Våra resultat indikerar att regelbunden HIIT efter tre månader kan minska nivåerna av serum kalprotektin. HIIT kan därför övervägas att vara en icke-farmakologisk behandling för axSpA patienter. Fler studier med en större axSpA population är nödvändigt för att vidare studera om HIIT påverkar serum kalprotektin.

High-intensity interval training (HIIT) consists of short intervals of exercise at high intensity intermitted by intervals of lower intensity and is associated with improvement of body composition and metabolic health in adults. Studies in overweight adolescents are scarce. We conducted a randomized controlled trial in overweight adolescents to compare acceptance and attendance of HIIT with or without weekly motivational encouragement through text messages and access to a study website. HIIT was offered for six months (including summer vacation) twice a week (60 min/session). Participation rates were continuously assessed and acceptance was measured. Clinical parameters were assessed at baseline and after six months. Twenty-eight adolescents participated in this study (age 15.5 +/- 1.4; 54% female). The standard deviation score for body mass index over all participants was 2.33 at baseline and decreased by 0.026 (95% CI - 0.048 to 0.10) units, p = 0.49. Waist to height ratio was 0.596 at baseline and decreased by 0.013 (95% CI 0.0025 to 0.024), p = 0.023. Participation within the first two months ranged from 65% to 75%, but fell to 15% within the last three months. Attendance in the intervention group was 14% (95% CI - 8 to 37), p = 0.18, higher than the control group. Overall program content was rated as \"good\" by participants, although high drop-out rates were observed. Summer months constitute a serious problem regarding attendance. The use of media support has to be assessed further in appropriately powered trials.

A redução nos níveis de atividade física nos últimos tempos, devido ao aumento do uso de novas tecnologias e a vida sedentária, agregada ao consumo excessivo de alimentos, tem promovido uma epidemia de obesidade e doenças metabólicas. No contraponto deste caminho, está a realização de exercícios físicos. O exercício intervalado surge como uma boa opção para a obtenção de bons resultados físicos, principalmente, quando as pessoas possuem um tempo reduzido para a realização do seu treinamento. Muitos esportes como futebol, vôlei, tênis e atletismo, assim como o exercício intervalado, necessitam de indivíduos que possam competir, ou simplesmente praticar, várias vezes dentro de um intervalo de poucos dias. Atletas profissionais ou amadores treinam quase todos os dias e necessitam de uma intervenção dietética para manter o seu nível de energia estável para a realização de treinos e partidas, fazendo uso frequente de suplementos alimentares. Dentro desta gama de suplementos alimentares a Creatina é um dos mais utilizados coadjuvantes na melhoria do desempenho atlético, demonstrando potencial aumento de força, bem como aumento de massa magra, o que pode estar relacionado com o sistema do fator de Crescimento semelhante à insulina 1 (IGF-1) ou o seu receptor celular o IGF-1R. O objetivo deste trabalho foi analisar o impacto da suplementação de Creatina juntamente com o treinamento intervalado de alta intensidade na expressão proteica de IGF-1R no tecido muscular, além de analisar as concentrações sanguíneas de lactato e glicemia, avaliar o desempenho ou a performance, dos ratos antes e após o treinamento intervalado e verificar o ganho de peso dos animais nos diferentes grupos. Trinta e sete (37) ratos Wistar machos com 75 dias no começo do experimento foram randomizados e separados em três grupos: A (Treinado sem suplementação, 13 animais), B (Treinado suplementado com Creatina e Carboidrato, 12 animais) e C (Treinado suplementado com Creatina, 12 animais). O protocolo de treinamento consistiu em 1 minuto de exercício a 110% da velocidade de fadiga do teste máximo em esteira, seguidos por 30 segundos a 40% desta, totalizando 30 min, cinco vezes por semana durante trinta e dois dias corridos. A suplementação de Creatina ocorreu durante todo o período de treinamento, duas horas antes do exercício. A água foi utilizada como veículo de infusão nos grupos A e C e uma solução de glicose a 10% no grupo B. Como resultado foi verificada uma melhoria no desempenho físico dos ratos em todos os grupos. Bem como uma maior expressão proteica do IGF-1R nos grupos treinados suplementados (B e C) quando comparados ao grupo treinado sem suplementação (A). Já os dados de glicemia, lactato e ganho de massa não apresentaram diferença significativa entre os grupos. Conclui-se que o treinamento intervalado de alta intensidade se apresenta como uma boa opção para melhorias na performance física, e que a suplementação de Creatina está envolvida no aumento da expressão proteica do IGF-1R. Contudo o protocolo de treinamento e suplementação utilizados no estudo não se refletiram em diferenças nas análises glicemia, lactato e massa dos animais. / The reduction in levels of physical activity in recent times, due to the increased use of new technologies and sedentary life, added to the excessive consumption of food, has promoted an epidemic of obesity and metabolic diseases. In contrast this way, is physical exercises. The interval exercise appears as a good option for getting good physical results, mainly, when people don’t have enough time to do their training. Many sports such as football, volleyball, tennis and athletics, as well as the interval exercise, require athletes to compete, or simply practicing several times within a few days. These professional or amateur athletes train almost every day and need a dietary intervention to keep your energy level stable for training and matches appropriately, making use often, dietary supplements. Within this range of dietary supplements, Creatine is one of the most used resource for improving athletic performance, demonstrating increased strength and power, as well as increased lean mass, which may be related to the insulin-like growth factor 1 (IGF-1) system or its cellular receptor IGF-1R. The aim of this study was to analyze the impact of creatine supplementation along with high intensity interval training on protein expression of IGF-1R in muscle tissue, and analyzing blood concentrations of lactate and glucose, evaluate the performance of rats before and after interval training, examine the weight gain of the animals in different groups. Thirty-seven (37) male Wistar rats at 75 days at the beginning of the experiment were randomly divided into three groups: A (Trained without supplementation, 13 animals), B (Trained supplemented with creatine and Carbohydrate, 12 animals) and C (Trained supplemented with creatine, 12 animals). The training protocol consisted of a 1 minute to 110% of the test speed of fatigue, followed by 30 seconds at 40% of this, totaling 30 minutes, five times a week for consecutive thirty-two days. The creatine supplementation occurred throughout the training period, two hours before the exercise, with water as a vehicle for infusion in groups A and C, and 10% glucose solution in group B. As a result we had improvement in physical performance of rats in all groups. As well as increased protein expression of IGF-1R in groups trained supplemented (B and C) when compared to the trained group without supplementation (A). Meanwhile, data from the glucose, lactate and mass gain did not differ significantly between groups. It is concluded that high-intensity interval training is presented as a good option to improve physical performance, and that creatine supplementation is involved in the increased protein expression of IGF-1R. The training and supplementation protocol used in the study were not reflected in differences in the analysis of IGF-1R, glucose, lactate and gain mass in the animals.

Training studies involving competitive runners and road cyclists have shown substantial gains in sprint and endurance performance when sessions of high-intensity interval training were added to their usual training in the competitive phase of a season. Further research has shown large performance benefits in sprint and endurance power (7 - 9%) when cyclists combined explosive single-leg jumps with cycling-specific high-intensity interval training during a competitive season. The aim of the present study was to assess the contribution of the jumps to the gains in performance in competitive cyclists in a randomized control trial.The training protocol for the control group was based on previous experimental work in which the control group (n=8) completed cycle specific interval training followed by a series of explosive single-leg jumps. The experimental group (n=7) carried out the same cycle specific interval training but did not participate in the explosive single-leg jumps. While the current study did not use a true control group, the investigation was carried out in the knowledge that a combination of high intensity interval cycling and explosive single-leg jumps causes changes positive changes in performance. Participants took part in 10 x 30-min sessions consisting four sets of high intensity intermittent cycling (4 x 30-s maximum efforts at 50 - 60 min-1 alternating with 30-s recovery). Between each set of 4 x 30 s sprints the control (ballistic) group carried out one set of explosive single-leg jumps (20 for each leg), while the experimental (continuous) group cycled for 20 s at 50 - 60 min-1.Before and after the training period all cyclists completed an incremental peak power test for assessment of VO2max, lactate threshold, exercise economy and peak power, a 30 s Wingate sprint test and a 20 km time-trial. Relative to the control group the percent mean changes (±90% confidence limits) in the experimental group were: power at 4-mM lactate, -4.2 (±6.3); VO2max, -3.1 (±3.7); mean time-trial power, -0.7 (± 4.7); peak incremental power, -1.7; (±5.0); power at 80% max heart rate, -2.8; (±5.6); Wingate peak power, -4.2; (±7.8). We conclude that high-intensity training may improve performance but the combination of high-intensity training and explosive resistance training in the competitive phase is likely to produce greater gains in trained cyclists than high intensity cycling alone.

Training studies involving competitive runners and road cyclists have shown substantial gains in sprint and endurance performance when sessions of high-intensity interval training were added to their usual training in the competitive phase of a season. Further research has shown large performance benefits in sprint and endurance power (7 - 9%) when cyclists combined explosive single-leg jumps with cycling-specific high-intensity interval training during a competitive season. The aim of the present study was to assess the contribution of the jumps to the gains in performance in competitive cyclists in a randomized control trial.The training protocol for the control group was based on previous experimental work in which the control group (n=8) completed cycle specific interval training followed by a series of explosive single-leg jumps. The experimental group (n=7) carried out the same cycle specific interval training but did not participate in the explosive single-leg jumps. While the current study did not use a true control group, the investigation was carried out in the knowledge that a combination of high intensity interval cycling and explosive single-leg jumps causes changes positive changes in performance. Participants took part in 10 x 30-min sessions consisting four sets of high intensity intermittent cycling (4 x 30-s maximum efforts at 50 - 60 min-1 alternating with 30-s recovery). Between each set of 4 x 30 s sprints the control (ballistic) group carried out one set of explosive single-leg jumps (20 for each leg), while the experimental (continuous) group cycled for 20 s at 50 - 60 min-1.Before and after the training period all cyclists completed an incremental peak power test for assessment of VO2max, lactate threshold, exercise economy and peak power, a 30 s Wingate sprint test and a 20 km time-trial. Relative to the control group the percent mean changes (±90% confidence limits) in the experimental group were: power at 4-mM lactate, -4.2 (±6.3); VO2max, -3.1 (±3.7); mean time-trial power, -0.7 (± 4.7); peak incremental power, -1.7; (±5.0); power at 80% max heart rate, -2.8; (±5.6); Wingate peak power, -4.2; (±7.8). We conclude that high-intensity training may improve performance but the combination of high-intensity training and explosive resistance training in the competitive phase is likely to produce greater gains in trained cyclists than high intensity cycling alone.