Kranskärlssjukdom (CAD) är den ledande dödsorsaken. Sjukdomen startar med plackbildning i ett eller flera kranskärl, vilket kan leda till bröstsmärta samt andra symtom. Diagnostik av CAD inkluderar undersökningarna arbetsprov (AP) och myokardscintigrafi (MPI). Båda undersökningarnas prognostiska värde påverkas dock av parametrar som elektrokardiogram (EKG), EKG-triggning, Dukes löpbands index (DTS) och Metaboliska ekvivalenter (MET). Litteraturstudiens syfte var att jämföra den prognostiska prestandan hos AP jämfört med MPI. Detta genom att studera de nämnda parametrarnas prognostiska påverkan på respektive undersökning. De använda artiklarna uppfyllde samtliga inklusionskriterier: engelska, peer-reviewed samt etiskt godkänd eller inhämtat samtycke. Databasen Pubmed, snowballsmetod samt relaterade artiklar användes vid litteraturinsamlingen. Enligt resultatet ökar ovannämnda parametrar det prognostiska värdet hos både AP och MPI. Dock visades att patienter som uppnår olika MET samt DTS-värden bättre kan riskkategoriseras med MPI. Dessutom visades MPI kunna skilja de med sämre prognos bland patienter med positiva AP-resultat, men även bland de med negativa AP-resultat. Därmed drog författarna slutsatsen att MPI har ett ökat mervärde gällande prognostik hos patienter med CAD. Fler studier som samtidigt jämför AP och MPI behövs dock för en mer fullständig slutsats. / Coronary artery disease (CAD) is the leading cause of death. This disease starts with plaque buildup in one or more coronary vessels, which can lead to chest pain among other symptoms. Diagnostics include the exercise stress test (AP) and myocardial scintigraphy (MPI). The prognostic value of both examinations depends on parameters such as electrocardiogram (ECG), ECG-gating, Duke treadmill score (DTS) and Metabolic equivalents (MET). The purpose of this study was to compare the prognostic performance of AP with MPI, by studying the prognostic effect of the mentioned parameters in each study. The used articles met all inclusion criterias: English, peer-reviewed, and ethically accepted or obtained consent. Pubmed database, snowball method and related articles were used for literature collection. According to the results, the above-mentioned parameters increase the prognostic value of AP and MPI. However, patients achieving different MET and DTS scores are better categorized with MPI. MPI was shown to differentiate those with poorer prognosis among patients with positive AP-results and those with negative AP-results. The authors concluded that MPI has an added value regarding prognosis forpatients with CAD. However, more studies comparing AP and MPI at the same time are needed to obtain a more complete conclusion.

The purposes of the study were to compare ratings of perceived exertion of aerobic dance and treadmill performances under equal work loads and to compare ratings of perceived exertion by males and females in aerobic dance and treadmill work. Subjects were twenty-six college men and women in co-educational conditioning classes. Heart rates were monitored after work bouts and perceived exertion was determined using Borg's RPE scale. Data were analyzed by a two-way analysis of variance with repeated measures. Conclusions of the investigation were: (1) aerobic dance is perceived as less strenuous than the treadmill under equal work loads, and (2) males and females perceive aerobic dance as less strenuous than the treadmill under equal energy bouts.

Angina pectoris är bröstsmärta orsakat av myokardischemi, till följd av kranskärlsjukdom med eller utan stenoser eller icke kranskärlsjukdom. Arbetsprov är den vanligaste undersökningen för angina pectoris. Diffusa symtom och angina pectoris varianter utan stenoser med låg sensitivitet för elektrokardiografi (EKG) sänker den diagnostiska säkerheten i arbetsprov på kvinnor. Litteraturstudiens syfte var att utreda om hemodynamiska parametrar och riskbedömning med Pre-test sannolikhet (PTP) samt Dukes Löpbands Index (DTS, Dukes Treadmill Score) kan öka den diagnostiska säkerheten i arbetsprov på kvinnor. Inklusionskriterierna var vetenskapligt granskade kliniska studier på engelska, med information om etiskt godkännande eller samtycke. Snowballing metoden, PUBMED, MEDLINE och CINAHL användes. Studier som inkluderades i resultatet granskades återigen och jämfördes med varandra. Hemodynamiska parametrar, PTP och DTS ökar den diagnostiska säkerheten i arbetsprov på kvinnor. Denna diagnostiska säkerhet beror dock också på PTP metod, PTP riskgrupp, etnicitet och angina pectoris variant. Vidare forskning behövs om etnicitetspecifika PTP metoder, mekanismen bakom blodtrycksreaktionen, DTS på icke kranskärlsjukdomar samt metoder som kan skilja mellan olika icke kranskärlsjukdomar. Utan studier om Systematic COronary Risk Evaluation (SCORE) och Diamond Forrester Score (DFS) samt deras påverkan på arbetsprov, kan inte resultatet i litteraturstudien generaliseras till arbetsprov i Sverige. / Angina pectoris is chest pain and myocardial ischemia due to Coronary Artery Disease (CAD) or Non-Coronary Artery Disease (non-CAD). Exercise stress test (EST) is the most common diagnostic procedure for angina pectoris. Non-CAD, low sensitivity for exercise electrocardiography (ex-ECG) and diffuse symptoms lower the diagnostic accuracy for females. This review’s aim was to study whether haemodynamic parameters and risk stratifications with Pre-test probability (PTP) or Duke Treadmill Score (DTS) improves the diagnostic accuracy of EST for females. Inclusion criterions were English peer reviewed, clinical studies with mentioned ethical approval or consent. Snowballing, PUBMED, MEDLINE and CINAHL were used. Articles that were included in the results, were reviewed once again, and compared to one another. Hemodynamic parameters, PTP and DTS increase the diagnostic accuracy of EST in women. This diagnostic accuracy depends on PTP method, risk group, ethnicity, and angina pectoris variant. Further research regarding ethnic specific PTP methods, mechanism behind the blood pressure reaction, DTS for diagnosis of non-CAD and methods for differentiation of subtypes of non-CAD, would be valuable. Without studies about the Systematic Coronary Risk Evaluation (SCORE), Diamond Forrester Score (DFS), and their impact on ex-ECG, the result of this review cannot be generalized to ex-ECG in Sweden.

Il est bien établi chez les physiologistes, que si l’exercice de course en montée sollicite préférentiellement des contractions musculaires concentriques, l’exercice de course en descente requiert des actions musculaires frénatrices, majoritairement excentriques. L’exercice de course en descente à intensité sous-maximale génère un stimulus mécanique plus important pour un niveau de sollicitation métabolique moindre (i.e., V̇O2). Basée sur 3 études expérimentales, cette thèse de doctorat explore la physiologie spécifique de la course en déclivité, ainsi que ses prédicteurs physiologiques. Notre première étude montre une amplitude des réponses cardiorespiratoires amoindrie, une ventilation plus superficielle et une composante lente négative de consommation d’oxygène et de fréquence cardiaque en course en descente versus montée à vitesse constante et identique (8,5 km·h-1, pente de 15%). Lors de tests incrémentaux maximaux en course en descente vs montée vs plat, notre 2ème, partie A étude démontre que des coureurs bien entraînés, familiarisés avec la course en descente, peuvent atteindre FCmax, mais pas V̇O2max en descente. Lorsque les courses en descente et montée sont réalisées à même intensité métabolique (70% V̇O2max), notre 2ème (B) étude démontre que la course en descente (19 km·h-1, pente de -15%) induit des réponses cardiorespiratoires supérieures (FC et V̇E), une composante lente de V̇O2 significative et engendre une fatigue supérieure à la course en montée (6 km·h-1, pente de +15%). Enfin, une étude de terrain (étude 3) montre que les performances de 5 km de course en montée et en descente partagent quelques prédicteurs physiologiques communs (V̇O2max, force musculaire des membres inférieurs), bien que dans des proportions différentes. De plus, ces deux contre-la-montre sont également déterminés par des prédicteurs physiologiques spécifiques (i.e., raideur musculo-tendineuse en descente et indice de masse corporelle en montée). Nos résultats améliorent notre compréhension de la physiologie spécifique à la course en descente vs montée et ouvrent la voie des applications à l’entraînement des traileurs avec le but ultime d’optimiser leur performance. / It is admitted that uphill running mostly elicits concentric muscle actions whereas downhill running requires braking muscle actions inducing preferentially eccentric muscle action. Consequently, high running speed can be achieved in downhill (i.e., a high level of mechanical stress), despite low metabolic demands (i.e., low metabolic power). Using 3 experimental studies, this doctoral thesis explores the specific physiology of downhill vs uphill running as well as its physiological determinants. Our first study shows lower magnitude of the cardiorespiratory responses, a more superficial ventilation pattern and inverse V̇O2 and HR slow components in submaximal constant and same downhill vs uphill running velocity (8,5 km·h-1, 15% slope). During maximal incremental downhill vs uphill and level running, our study 2 part A demonstrates that well-trained endurance athletes, accustomed to downhill running, can reach maximal heart rate but not V̇O2max in downhill running. When downhill and uphill running are performed at similar metabolic demand (70% V̇O2max), our study 2 part B demonstrates that downhill running (19 km·h-1, -15% slope) elicits greater cardiorespiratory responses (HR and V̇E), a significant V̇O2 slow component and exacerbates muscle fatigue compared to uphill running (6 km·h-1, +15% slope). Finally, a field study (study 3) shows that 5-km downhill vs uphill running performances share some physiological predictors (V̇O2max, lower limb muscle strength) although in different proportions. In addition, this study also demonstrates that both time-trial performances are also determined by specific physiological predictors (i.e., musculotendinous stiffness for downhill and body mass index for uphill running). All in all, our results further our understanding of the specific physiology of downhill vs uphill running and open the way to training applications in trail runners with the ultimate goal to optimize trail running performance.

Introduction: Maximum running acceleration essential components in many sports. The identification of specific training protocols to maximize sprint speed would be useful knowledge for soccer coaches and players. Purpose: The purpose of this study was to determine the effect of a high-speed treadmill with the use of a body-weight support system in a 6-week sport acceleration program on: 40-yard sprint time, maximal isometric knee flexor and extensor strength. Methods: 32 female soccer players (age 16 ± 1.19 yrs) participated in two treatment groups and one control group. Both treatment groups participated in a 12-session sport acceleration program. The first treatment group utilized a body-weight support system while on a high-speed treadmill; the second group used a standard treadmill with no body weight support system. The control group, NT, did not participate in a sports acceleration program and did not alter their exercise routines outside of the study. Results: For each variable an Analysis of Covariance (ANCOVA) was performed. 40-yard sprint times for treatment groups were shown to improve significantly as compared to the control group (p = 0.0007 for high-speed treadmill with body-weight support system, p= < 0.0001 for standard treadmill without body-weight support system). Isometric flexor and extensor strengths did not show significant differences between treatment groups and control group. P-values for the high-speed with body-weight support system were (p = 0.53) for flexors and (p = 0.51) for extensors as compared to the control group. P-values for the standard treadmill with no body-weight support system were (p = 0.19) for extensors and (p = 0.0263) for flexors. It is noted that the extensor muscles were nearly significant for the standard treadmill with no body-weight support system. Discussion: These results can help high school coaches and athletes determine the optimal treadmill training regime. The current study shows that a high-speed treadmill with body-weight support system is just as beneficial as standard treadmill training.

Agrarbasierte Volkswirtschaften in Afrika streben danach, die Produktivität und Produktion gemäß den Empfehlungen der Afrikanischen Union zu steigern. Allerdings kann eine bloße Produktionssteigerung den Landwirten schaden, wenn die Ab-Hof-Preise fallen als die Produktionskosten. Diese Dissertation analysiert die Implikationen der Verbesserung landwirtschaftlicher Wertschöpfungsketten am Beispiel Benin. Eine detaillierte Social Accounting Matrix (SAM) für Benin aus dem Jahr 2019 wird erstellt, die offizielle Statistiken und Stakeholder-Umfragedaten integriert. Diese SAM dient als Grundlage für die Kalibrierung von Computable General Equilibrium (CGE) Modellen, um die gesamtwirtschaftlichen Auswirkungen der Entwicklung landwirtschaftlicher Wertschöpfungsketten zu analysieren. Die Forschung zeigt, dass die Entwicklung des Lebensmittelverarbeitungssektors, beispielhaft durch die Verarbeitung von Cashewkernen und Ananas, positive, armutsreduzierende Wohlfahrtseffekte hat und zum Wirtschaftswachstum beiträgt. Präferenzverschiebungen hin zu heimischem Geflügelfleisch stellen eine Alternative zu Handelspolitiken dar, um den heimischen Sektor zu stärken. Die Verarbeitung von Cashew-Nebenprodukten birgt Potenzial für die wirtschaftliche, soziale und ökologische Nachhaltigkeit der Agrar- und Ernährungssysteme. Investitionen in eine stabile Strominfrastruktur zur Unterstützung des industriellen Wachstums können die Produktionskosten senken und die Nachfrage nach landwirtschaftlichen Produkten erhöhen, was insbesondere einkommensschwachen Haushalten zugutekommt. Insgesamt kommt die Studie zu dem Schluss, dass die Entwicklung landwirtschaftlicher Wertschöpfungsketten in agrarwirtschaftlich geprägten Volkswirtschaften das Haushaltseinkommen erhöht, die Armut verringert, die makroökonomischen Indikatoren verbessert und die allgemeine wirtschaftliche Entwicklung fördert. / Agriculture-based economies in Africa are striving to boost productivity and production following the African Union's recommendations. However, merely increasing production can harm farmers if farm-gate prices drop more than production costs. Research on the broader economic effects of agricultural value-chain development is limited. This thesis addresses this gap by examining the economy-wide implications of enhancing agricultural value-chains, using Benin as a case study. A detailed 2019 Social Accounting Matrix (SAM) for Benin is constructed, incorporating official statistics and stakeholder survey data. This SAM is used as the basis for calibrating Computable General Equilibrium (CGE) models. These models were adapted to analyze the impact of developing the food-processing sector, preference shifts, and stable electricity supply on the economy. The research reveals that developing the food-processing sector, exemplified by cashew nut and pineapple processing, has positive, pro-poor welfare effects and contributes to economic growth. Preference shifts towards domestic poultry meat is an alternative to trade policies in boosting the domestic sector. Processing of cashew byproducts has potential for economic, social and environmental sustainability of the agri-food systems. Investing in stable electricity infrastructure to support industrial growth can reduce production costs and increase demand for agricultural products, benefiting low-income households disproportionately. Overall, the study concludes that developing agricultural value-chains in agriculture-based economies enhances household income, reduces poverty, improves macroeconomic indicators, and fosters overall economic development.

L’asymétrie de longueur de pas est une caractéristique du patron de marche fréquemment observée chez des personnes qui ont subi un accident vasculaire cérébral (AVC). Très peu d’interventions conventionnelles en réadaptation ont démontré leur efficacité sur ce paramètre de marche. Une approche novatrice utilisant un tapis roulant à double courroie (DC) a récemment présenté des effets prometteurs en réduisant, à court et long termes, l’asymétrie de longueur de pas chez des personnes post-AVC. Cependant, une meilleure compréhension des mécanismes sous-jacents aux changements induits par cette intervention est nécessaire avant que l’utilisation de cette intervention soit recommandée en clinique. Ce projet doctoral visait à améliorer les connaissances sur la contribution musculaire et les facteurs biomécaniques impliqués dans les changements immédiats (c.-à-d. les post-effets) et à long terme de l’asymétrie de la longueur de pas chez des personnes post-AVC. Les objectifs principaux étaient 1) d’analyser l’activité musculaire associée aux changements de longueur de pas après la marche sur un tapis à DC avec des vitesses de courroies inégales, 2) d’évaluer les effets d’un entraînement sur un tapis à DC sur l’asymétrie de longueur de pas et sur la capacité de marche au sol et 3) de quantifier la contribution musculaire et les stratégies sous-jacentes aux changements du patron de marche résultant de l’entraînement. L’hypothèse générale était que les muscles distaux des membres inférieurs seraient majoritairement impliqués dans les changements de longueur de pas induits par la marche sur le tapis à DC avec des vitesses de courroies inégales (ratio 2:1) chez les personnes post-AVC. L’étude transversale (article #1) a quantifié l’activité musculaire des membres inférieurs associée aux post-effets observés au niveau de la longueur de pas après six minutes de marche sur le tapis à DC (ratio 2:1) chez 16 personnes post-AVC et 10 personnes saines. Les résultats ont confirmé que les muscles distaux, c.-à-d. les fléchisseurs plantaires et dorsaux, étaient associés aux post-effets de la longueur de pas. Ces effets ont été observés, quel que soit le membre inférieur (c.-à-d. parétique ou non parétique) qui était sur la courroie rapide. La deuxième étude, a démontré que six séances d’entraînement sur le tapis à DC conduisaient à une réduction de l’asymétrie de longueur de pas et amélioraient la vitesse de marche sur le sol chez 12 personnes post-AVC (article #2). Les changements ont persisté un mois après l’entraînement. En outre, les résultats de cette étude pilote ont suggéré une bonne faisabilité de ce protocole d’entraînement dans un environnement clinique (données supplémentaires de l’article #2). Dans l’article #3, il a été démontré que l’amélioration post-entraînement de la symétrie et de la vitesse de marche était associée à une variété de stratégies et de contributions musculaires chez nos participants. Cependant, une contribution prédominante a été observée au niveau du membre inférieur entraîné sur la courroie rapide avec des tailles d’effet modérées obtenues surtout pour les changements de moment et d’activité musculaire des fléchisseurs plantaires pendant la phase d’appui de la marche. Suite à ces résultats et ceux de l’article #1, il a été suggéré que ce groupe musculaire jouait un rôle principal dans l’adaptation locomotrice et la réduction à long terme de l’asymétrie de la longueur de pas chez des personnes post-AVC. Néanmoins, des études cliniques contrôlées avec une population plus importante sont nécessaires afin de préciser la pertinence de l’entraînement sur le tapis à DC ainsi que les différentes stratégies musculaires associées aux changements de l’asymétrie de longueur du pas à long terme chez des personnes post-AVC. / Step length asymmetry is a common characteristic of post-stroke gait, but considered as particularly resistant to conventional gait interventions. A recent novel approach using a split-belt treadmill (SBT) showed promising results in short- and long-term reduction of step length asymmetry post-stroke. However, the underlying mechanisms of this intervention and its effects must be better understood before recommending its use in clinical settings. This project aimed to improve our current knowledge about muscular and biomechanical factors contributing to immediate and long-term changes in step length asymmetry in chronic stroke survivors. The main objectives were to: 1) analyze muscle activity associated with changes in step length after walking at unequal belt speeds on a SBT; 2) test the effects of repeated exposure to SBT walking on step length asymmetry and gait ability during walking over ground; and 3) investigate the muscular contributions and strategies involved in these changes. To attain these objectives, a cross-sectional analysis was conducted followed by a pilot training study. The general hypothesis was that distal lower limb muscles are the main contributors to SBT-induced changes in step length asymmetry in chronic stroke survivors using a SBT protocol where two belts were set at unequal speeds with a ratio of 2:1 for a period of time (split-belt configuration). The cross-sectional study analyzed the immediate changes in muscle activity and step length after six minutes of SBT walking in a group of 16 individuals post-stroke and in 10 healthy controls. The findings confirmed that regardless of the side (paretic or non-paretic) walking on the fast belt during split-belt configuration, changes in muscle activity of the ankle plantar- and dorsiflexors were mainly associated with changes in step length symmetry (paper #1). The pilot training study demonstrated that repeated exposure to SBT protocol reduced step length asymmetry and improved walking speed over ground in 12 individuals post-stroke (paper #2). Improvements persisted at least one month post-training. Findings also indicated that from a therapist’s viewpoint the training protocol was easy to use and practical in a clinical environment (supplementary data paper #2). Paper #3 showed that these consistent improvements in gait parameters were achieved by a variety of muscular contributions and strategies which involved both lower limbs with a predominant contribution on the side that was trained on the faster belt. Large effect sizes were found in the plantarflexor group during late stance of gait for both net joint moments and muscle activity in the training study. These results combined with the findings of paper #1 indicate that overall, step length asymmetry post-stroke can be successfully reduced with repeated exposure to the tested SBT protocol with distal lower limb muscles appearing to be strong contributors to locomotor adaptation post-stroke and long-term changes in step length asymmetry. Larger control trials are necessary to confirm the relevance of the use of SBT protocols and to further understand the role of the distal lower limb muscles in improvements in step length symmetry post-stroke.

Syfte och frågeställningar. Syftet med studien är att, hos äldre personer, över 65 år, samt hos yngre vuxna, mellan 20-30 år, jämföra syreupptagningsförmågan med två olika metoder, fem-minuterspyramidtest (5MPT) samt VO2max-test på löpband. Vid båda mätmetoderna används direkt syrgasmätning. Metod. Totalt deltog 36 personer i studien, varav 17 äldre personer 65 till 85 år (9 kvinnor och 8 män) samt 19 yngre med en ålder mellan 20 till 35 år (10 kvinnor och 9 män). Deltagarnas syreupptagningsförmåga mättes under 5MPT vid två tillfällen som sedan jämfördes med VO2max mätt via ett maximalt test på löpband vid ett tillfälle. Således utfördes sammanlagt tre mätningar med direkt syrgasmätning, via andningsmask, under ett maximalt löpbandstest samt under två separata tester av 5MPT med minst 48 timmar mellan varje testtillfälle. Utandningsluften analyserades sedan, vid 5MPT för alla, via det trådlösa portabla systemet Jaeger Oxycon Mobile och vid test på löpband för testgruppen med yngre deltagare. För den testgrupp med äldre deltagare användes, vid testet på löpband, den fasta on-line-utrustningen Jaeger Oxycon Pro som är en liknande mätmetod för syreupptag. 5MPT är ett fem minuter långt test där individen från golvnivå, med högsta möjliga tempo, förflyttar sig fram och tillbaka på en 5,50 meter lång sträcka med en centralt placerad trappramp som är pyramidformad och med en högsta central höjd på 0,62 meter. Resultat. Det primära fyndet i studien var att en stark signifikant korrelation (r = 0,99) visade sig mellan direkt uppmätt VO2max under maximalt test på löpband gentemot syreupptagningsförmågan vid 5MPT då båda åldersgrupperna var sammanslagna, uppmätt i l·min–1. Slutsats. Då det i undersökningen visades en stark signifikant korrelation mellan direkt uppmätt VO2max vid 5MPT och ett maximalt test på löpband i l·min–1 för äldre och yngre vuxna ger det indikationer på att 5MPT kan används som en tillförlitlig metod vid undersökning och uppföljning av en persons aeroba förmåga. Fyndet kan vara av värde då det genom mindre kostsamma och enklare metoder går att få ett mått på en persons hälsa i form av aerob kapacitet, vilket är betydelsefullt ur flera hälsoaspekter på individ- och samhällsnivå. / Aim. The purpose of the study was to investigate the results and correlation between oxygen uptake levels (VO2max) at five-minute pyramid test (5MPT) against maximal oxygen uptake test (VO2max) on a treadmill test, both measured by direct oxygen measurement, in elderly people over 65 years and younger adults aged 20-30 years. Method. A total of 36 people participated in the study, 17 elderly people aged between 65 to 85 years (9 women and 8 men) and 19 younger adults aged between 20 to 35 years (10 women and 9 men). The participants' oxygen uptake was measured twice during 5MPT and then compared with VO2max measured by a maximal treadmill test at one occasion. Thus a total of three measurements with direct oxygen measurement, via the breathing mask, during a maximum treadmill test and two separate tests of 5MPT with at least 48 hours between each test. The exhaled air was analyzed at 5MPT for all, through the wireless portable system Jaeger Oxycon Mobile and also during the test on treadmill for the test group with younger participants. The test group of older participants, got their exhaled air analyzed through a stationary on-line equipment Jaeger Oxycon Pro instead of the portable system which is a similar reliable method to measure VO2max. 5MPT is a five minute test where the subjects from floor level, with the highest possible speed, moves back and forth at a measured distance of 5.50 meter with a central staircase ramp, which is pyramid-shaped, with a maximum center height of 0.62 meters. Results. The main finding of the study was that there was a strong significant correlation (r = 0.99) between directly measured VO2max during a maximum treadmill test compared to oxygen uptake at 5MPT when both the elderly people and the younger adults were combined, measured in l·min–1. Conclusion. The study showed a strong significant correlation between directly measured VO2max at 5MPT and a maximal treadmill testing l·min–1 for older and younger adults. This indicates that 5MPT can be used as a reliable method for investigation and monitoring a person’s aerobic capacity. This finding may be of value because it shows that less expensive and easier methods can be used to measure a person's health in terms of aerobic capacity, which is important from several aspects of health at both the individual and society level.

Estratégia de corrida é forma pela qual os corredores distribuem a velocidade durante uma competição. Objetivando otimizar a utilização dos recursos energéticos, bem como melhorar o desempenho geral na prova, durante uma corrida de 5 km os atletas comumente adotam uma estratégia caracterizada por um início em alta velocidade, seguido por um trecho intermediário em velocidade inferior, e finalmente os atletas aumentam a velocidade quando se aproximam dos 400 m finais da prova. Sabe-se que o treinamento intervalado de alta intensidade (TIAI) realizado ao longo de 3 a 6 semanas é capaz de promover melhoras significativas nas variáveis fisiológicas determinantes do desempenho aeróbio, tais como VO2max, EC, VP, e OBLA. Uma vez que os atletas monitoram a PSE baseado em sinais internos (fisiológicos) e externos (ambiente), e desta forma alteram a velocidade para evitarem o término prematuro do exercício, acredita-se que melhoras em tais variáveis fisiológicas possam permitir que os corredores modifiquem a estratégia de corrida. Portanto, o principal objetivo do presente estudo foi analisar a influência de quatro semanas de TIAI sobre a PSE e também sobre a estratégia de corrida adotada por corredores durante um teste contra-relógio de 5 km (T5). Vinte sujeitos, homens, corredores recreacionais de longa distância foram distribuídos de forma contrabalançada em grupo controle (CON, n = 10; 33,5 ± 6,2 anos) e grupo treinamento intervalado (TINT, n = 10; 32,9 ± 8,6 anos). TINT realizou uma sessão de TIAI duas vezes por semana, enquanto que CON manteve seu programa regular de treinamento. Antes e após o período de intervenção, os corredores realizaram: 1) um teste incremental até exaustão para se obter o início do acúmulo de lactato sanguíneo (OBLA), o consumo máximo de oxigênio (VO2max), e a velocidade pico em esteira (VP); 2) um teste submáximo de carga constante para se medir a economia de corrida (EC); 3) e um teste contra-relógio de 5 km (T5) em pista para se estabelecer a estratégia de corrida. O programa de TIAI produziu uma melhora relevante no VO2max (effect size = 0,219), OBLA (effect size = 0,489), EC (effect size = -0,593), e VP (effect size = 0,622). Não foram detectadas alterações significativas na estratégia de corrida, TT5, VT5 e PSET5 durante o T5, comparando ambas as condições (pré e pós-treinamento) ou entre os grupos (TINT e CON; P > 0,05). Esses achados sugerem que melhoras nas variáveis fisiológicas induzidas por um programa de quatro semanas de TIAI não são acompanhadas por alterações similares na PSE e na estratégia de corrida durante um teste contra-relógio de 5 km / Pacing strategy has been defined as the manner by which the runners distribute their speed during a competition. In order to optimize the use of the energetic resources, as well as improve the general race performance, during a 5-km running race, athletes usually adopt a pacing strategy characterized by a fast start (400 m), followed by a period of slower speed during the middle (400 4600 m), and a significant increase in running speed during the last part of the race (400 m). It is well recognized that high-intensity interval training (HIIT) performed along 3 to 6 weeks is able to promote significant improvements in physiological variables determinants of endurance performance, such as VO2max, RE, PTS, and OBLA. Since athletes monitor their RPE based on the internal (physiological) and external (environment) signals, and change their running speed in order to prevent a premature exercise termination, its believed that improvements in such physiological variables could enable athletes to modify the pacing strategy. Thus, the main purpose of this study was to analyze the influence of 4 weeks of high-intensity interval training (HIIT) on the rating of perceived exertion (RPE) and the pacing strategy adopted by runners during a 5-km running time-trial (T5). Twenty male, recreational long-distance runners were randomly assigned into control group (CG, n = 10) or high-intensity interval-training group (HIITG, n = 10). The HIITG performed a high-intensity interval-training session twice per week, while CG maintained its regular training program. Before and after the training period, the runners performed the following tests: 1) an incremental exercise test to exhaustion to measure the onset of blood lactate accumulation (OBLA), maximal oxygen uptake (VO2max), and peak treadmill speed (PTS); 2) a submaximal speed-constant test to measure the running economy (RE); 3) a 5-km running time-trial on an outdoor track to establish pacing strategy. HIIT program produced a relevant improvement on the VO2max (effect size = 0.219), OBLA (effect size = 0.489), RE (effect size = -0.593), and PTS (effect size = 0.622). There were no significant differences on pacing strategy, TT5, ST5 and RPE response during the 5-km running time-trial between both conditions (pre- and post-training) or between groups (HIITG and CG; P > 0.05). These findings suggest that improvements on the physiological variables induced by a 4-week HIIT program are not accompanied by similar modifications on the RPE and running pacing strategy during a 5-km running time-trial

Estratégia de corrida é forma pela qual os corredores distribuem a velocidade durante uma competição. Objetivando otimizar a utilização dos recursos energéticos, bem como melhorar o desempenho geral na prova, durante uma corrida de 5 km os atletas comumente adotam uma estratégia caracterizada por um início em alta velocidade, seguido por um trecho intermediário em velocidade inferior, e finalmente os atletas aumentam a velocidade quando se aproximam dos 400 m finais da prova. Sabe-se que o treinamento intervalado de alta intensidade (TIAI) realizado ao longo de 3 a 6 semanas é capaz de promover melhoras significativas nas variáveis fisiológicas determinantes do desempenho aeróbio, tais como VO2max, EC, VP, e OBLA. Uma vez que os atletas monitoram a PSE baseado em sinais internos (fisiológicos) e externos (ambiente), e desta forma alteram a velocidade para evitarem o término prematuro do exercício, acredita-se que melhoras em tais variáveis fisiológicas possam permitir que os corredores modifiquem a estratégia de corrida. Portanto, o principal objetivo do presente estudo foi analisar a influência de quatro semanas de TIAI sobre a PSE e também sobre a estratégia de corrida adotada por corredores durante um teste contra-relógio de 5 km (T5). Vinte sujeitos, homens, corredores recreacionais de longa distância foram distribuídos de forma contrabalançada em grupo controle (CON, n = 10; 33,5 ± 6,2 anos) e grupo treinamento intervalado (TINT, n = 10; 32,9 ± 8,6 anos). TINT realizou uma sessão de TIAI duas vezes por semana, enquanto que CON manteve seu programa regular de treinamento. Antes e após o período de intervenção, os corredores realizaram: 1) um teste incremental até exaustão para se obter o início do acúmulo de lactato sanguíneo (OBLA), o consumo máximo de oxigênio (VO2max), e a velocidade pico em esteira (VP); 2) um teste submáximo de carga constante para se medir a economia de corrida (EC); 3) e um teste contra-relógio de 5 km (T5) em pista para se estabelecer a estratégia de corrida. O programa de TIAI produziu uma melhora relevante no VO2max (effect size = 0,219), OBLA (effect size = 0,489), EC (effect size = -0,593), e VP (effect size = 0,622). Não foram detectadas alterações significativas na estratégia de corrida, TT5, VT5 e PSET5 durante o T5, comparando ambas as condições (pré e pós-treinamento) ou entre os grupos (TINT e CON; P > 0,05). Esses achados sugerem que melhoras nas variáveis fisiológicas induzidas por um programa de quatro semanas de TIAI não são acompanhadas por alterações similares na PSE e na estratégia de corrida durante um teste contra-relógio de 5 km / Pacing strategy has been defined as the manner by which the runners distribute their speed during a competition. In order to optimize the use of the energetic resources, as well as improve the general race performance, during a 5-km running race, athletes usually adopt a pacing strategy characterized by a fast start (400 m), followed by a period of slower speed during the middle (400 4600 m), and a significant increase in running speed during the last part of the race (400 m). It is well recognized that high-intensity interval training (HIIT) performed along 3 to 6 weeks is able to promote significant improvements in physiological variables determinants of endurance performance, such as VO2max, RE, PTS, and OBLA. Since athletes monitor their RPE based on the internal (physiological) and external (environment) signals, and change their running speed in order to prevent a premature exercise termination, its believed that improvements in such physiological variables could enable athletes to modify the pacing strategy. Thus, the main purpose of this study was to analyze the influence of 4 weeks of high-intensity interval training (HIIT) on the rating of perceived exertion (RPE) and the pacing strategy adopted by runners during a 5-km running time-trial (T5). Twenty male, recreational long-distance runners were randomly assigned into control group (CG, n = 10) or high-intensity interval-training group (HIITG, n = 10). The HIITG performed a high-intensity interval-training session twice per week, while CG maintained its regular training program. Before and after the training period, the runners performed the following tests: 1) an incremental exercise test to exhaustion to measure the onset of blood lactate accumulation (OBLA), maximal oxygen uptake (VO2max), and peak treadmill speed (PTS); 2) a submaximal speed-constant test to measure the running economy (RE); 3) a 5-km running time-trial on an outdoor track to establish pacing strategy. HIIT program produced a relevant improvement on the VO2max (effect size = 0.219), OBLA (effect size = 0.489), RE (effect size = -0.593), and PTS (effect size = 0.622). There were no significant differences on pacing strategy, TT5, ST5 and RPE response during the 5-km running time-trial between both conditions (pre- and post-training) or between groups (HIITG and CG; P > 0.05). These findings suggest that improvements on the physiological variables induced by a 4-week HIIT program are not accompanied by similar modifications on the RPE and running pacing strategy during a 5-km running time-trial