Introduktion Längdskidor involverar såväl underkropps som överkroppsarbete i varierad intensitet och terräng. Tävlingarna är allt ifrån 1km upp till 30km för damer respektive 50km för herrar. Detta ställer flera olika fysiologiska krav på en längdskidåkare. Som exempelvis hög maximal aerob effekt, hög aerob kapacitet, hög anaerob kapacitet, styrka, kraftutveckling i överkropp samt hög andel fettfri massa. Tidigare studier visar att det finns en skillnad i fysiologiska egenskaper mellan sprint- och distansåkare. Det finns hittills ingen strukturerad litteraturundersökning som jämför den aktuella forskningen (från och med 2012) på skillnaderna i vilka fysiologiska egenskaper som är kopplade till sprint- respektive distansprestation. Syftet var att undersöka skillnaderna mellan vilka fysiologiska egenskaper som kan kopplas till sprintprestation och vilka fysiologiska egenskaper som kan kopplas till distansprestation inom elitlängdskidåkning. Metod En strukturerad litteraturundersökning utfördes i databaserna: Pubmed, SPORTDiscus och Sport Medicine and Education Index mellan 2012 och 2022-04-18. Även en manuell sökning i relevanta artiklars referenslistor utfördes. Resultat  Studien inkluderade 13 artiklar. Resultatet visade att sprintprestation är kopplat till högt VO2max (l/min). Distansprestation är kopplat till högt VO2max (l/min och ml/kg/min). Sprintåkare har högre VO2max uttryckt i l/min medan distansåkare har högre VO2max uttryckt i ml/kg/min vid jämförelse mellan disciplinerna. Hastighet på obla4mmol är kopplat till distansprestation men inte till sprintprestation. Hög anaerob kapacitet och större fettfri massa uttryckt i absoluta mått är starkare kopplat till sprintprestation än distansprestation.   Konklusion Distansprestation är kopplat till VO2max/VO2peak (l/min och ml/kg/min), aerob kapacitet samt hög andel fettfrimassa. Sprintprestation är kopplat till hög VO2max/VO2peak (l/min), anaerob kapacitet samt hög fettfri massa. Skillnaderna var att distansprestation var starkare kopplat till det aeroba egenskaperna i jämförelse med sprintprestation medan sprintprestation var starkare kopplat till det anaeroba egenskaper i jämförelse med distansprestation. / Introduction Cross-country skiing involves both upper- and lower body work in varied intensity and terrain. The distances are from 1km to 30km for women respectively 50km for men. There are different physiological demands on a cross-country skier. For example, high maximum aerobic power, high aerobic capacity, high anaerobic capacity, strength, upper body power and a high proportion of lean mass. Earlier studies have seen differences in physiological characteristics between sprint- and distance skiers. But there is no structured literature study that compares the current research (from 2012) on differences in physiological characteristics between sprint and distance performance. The aim was to investigate differences between physiological characteristics that can be linked to sprint and distance performance in elite cross-country skiing.  Method A structured literature review was conducted in the databases: PubMed, SPORTDiscus and Sports Medicine And Education Index between 2012 and 2022-04-18. A manual search in the reference lists of relevant articles was conducted. Results 13 articles were included in the study. The results showed that sprint performance is linked to high VO2max (l/min). Distance performance is linked to high VO2max (l/min and ml/kg/min). Sprint skiers have higher VO2max expressed in l/min while distance skiers have higher VO2max expressed in ml/kg/min in comparison with each other. Speed ​​at obla4mmol is linked to distance performance but not to sprint performance. High anaerobic capacity and greater lean mass are more strongly linked to sprint performance than distance performance. Conclusion Distance performance is linked to VO2max/VO2peak (l/min and ml/kg/min), aerobic capacity and high proportion of lean mass. Sprint performance is linked to high VO2max/VO2peak (l/min), anaerobic capacity and high lean mass. The differences were that distance performance was more strongly linked to the aerobic characteristics compared to sprint performance while sprint performance was more strongly linked to anaerobic characteristics compared to distance performance.

Thèse effectuée en cotutelle (Université de Poitiers, France) / Introduction – Le vieillissement est associé à une augmentation du coût énergétique de la locomotion (CE) et à une diminution de la consommation maximale d’oxygène (V ̇O2max). De plus, les qualités neuromusculaires semblent aussi compromises chez les aînés. Ces phénomènes contribuent au ralentissement de la vitesse de marche spontanée et peuvent altérer la qualité de vie. En plus de ces qualités physiques, il est reconnu que les fonctions cognitives déterminent la mobilité. En effet, la capacité de combiner une tâche motrice (locomotion) à une tâche cognitive est associée à une réduction du risque de chuter. Objectif – L’objectif de cette thèse était de préciser les relations entre la mobilité, la condition physique et les fonctions cognitives dans une perspective de vieillissement sain. Résultats – Une étude méthodologique a été présentée pour spécifier les modalités d’évaluation du CE. Les résultats ont démontré que le CE est plus élevé lorsque la mesure est effectuée sur tapis roulant en comparaison avec une mesure directement au sol. Il a aussi été suggéré que le niveau d’assocation entre les deux modalités était insatisfaisant. Ainsi, lorsque la mesure sur tapis roulant est nécessaire, elle doit idéalement être accompagnée d’un test de marche au sol pour améliorer la validité externe. Ensuite, une approche transversale a été utilisée afin de préciser les déterminants de la condition physique associés à une meilleure mobilité et à un profil cognitif favorable. En plus de la V ̇O2max, une force élevée caractérisait les individus qui présentaient les meilleures performances dans une tâche de flexibilité cognitive. Il a aussi été démontré que des tests cliniques comme le Timed up and go et la vitesse maximale de marche sur 10 mètres pouvaient être utilisés pour discriminer les individus qui présentent les profils physiques et cognitifs les moins favorables. Enfin, une étude d’intervention a été proposée afin de vérifier si un entraînement de l’aptitude aérobie et de la force visant une augmentation de la V ̇O2max et la réduction du CE allait permettre de meilleures performances cognitives lors d’une double tâche (motrice et cognitive). Les résultats démontrent, malgré que ce type d’intervention semble favoriser de meilleures performances en inhibition, qu’un programme visant le développement des habiletés motrices globales est aussi efficace pour induire des améliorations en inhibition. Conclusion – Ces résultats confirment la pertinence de l’évaluation d’un ensemble de déterminants de la condition physique allant de l’aptitude aérobie aux qualités neuromsuculaires dans le suivi de la santé physique et cognitive des aînés. Des tests cliniques accessibles sont proposés afin de contribuer à un premier diagnostic physique et cognitif qui saura être confirmé par des mesures plus exhaustives. Par ailleurs, il est aussi suggéré que plusieurs interventions peuvent être proposées pour améliorer les fonctions cognitives. Malgré que l’entraînement de l’aptitude aérobie et des qualités de force soit le seul à induire des améliorations de la condition physique, il n’en demeure pas moins qu’un programme de développement des habiletés motrices puisse représenter une avenue intéressante dans le cas où les individus étaient au préalable très sédentaires. / Introduction – Aging is characterized by an increase in the energy cost of locomotion (ECL) and a decrease in maximal oxygen uptake (V ̇O2max). It also appears that neuromuscular performances are jeopardized in older adults. Taken together, these phenomena contribute to a slower gait speed, which could reduce quality of life. Moreover, it was shown that cognition was also a key determinant of mobility performances. Indeed, the ability to execute simultaneously two tasks (motor and cognitive) was associated with a lower risk of falling. Objective – The objective of this thesis was to specify the relationships between mobility, physical fitness and cognition in a perspective of healthy aging. Results – A study was conducted to clarify the ECL testing methods. Results demonstrate a higher ECL when testing occurs on a treadmill in comparison to an overground measure. Moreover, it was shown that the association level was unsatisfying between the two testing modes. It was concluded that, when a treadmill testing is necessary, a complementary functional walking test should be implemented to increase external validity in data interpretation. Afterwards, a cross-sectional analysis was used to determine the physical fitness factors associated with better cognitive and mobility performances. Along with V ̇O2max, higher levels of strength were related to the fastest individuals both in mobility and in cognitive flexibility. Also, it was shown that clinical tests like the Timed up and go and the maximal walking speed over 10 meters were able to distinguish individuals with poorer physical fitness and cognitive performances. Finally, an intervention study was proposed to verify the effects of a combined aerobic and strength training program on physical fitness and cognition. It was hypothesized that reducing the ECL and increasing V ̇O2max would induce better cognitive performances during a dual-task (motor and cognitive). Results showed that this intervention improved inhibition performances. However, data also suggested that a training program aiming for gross motor abilities development was as efficient as the fitness training intervention to improve inhibition. Conclusion – Taken together, these results confirm the relevance of a complete physical fitness assessment in an healthy aging perspective including both aerobic and neuromuscular components. Convenient clinical tests are also proposed to establish a first physical and cognitive diagnosis, which will be confirmed by subsequent more exhaustive tests. Moreover, it was suggested that many interventions were leading to better cognitive performances. Along with aerobic and strength training which is a privileged method to improve physical fitness, programs aiming for gross motor abilities development could also be implemented, especially in a context where individuals are particularly sedentary.

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

Le modèle bioénergétique de P.E. di PRAMPERO permet d'expliquer la performance dans les disciplines de locomotion (course à pied, cyclisme, natation, ...) à partir d'une puissance métabolique et d'un indice de la dépense d'énergie par unité de distance parcourue. Néanmoins, pour les épreuves de natation de haute intensité telles que le 100m crawl, le contexte environnemental rend l'estimation de la puissance métabolique d'origine aérobie techniquement difficile. L'objectif de cette thèse est alors de proposer une nouvelle approche des réponses aérobies d'un 100-m nage libre, réalisé dans des conditions les plus proches possible d'une compétition. Le travail expérimental a porté sur des nageurs entraînés. Dans un bassin de 25-m, la procédure propose que les nageurs réalisent une performance sur 100-m nage libre à allure de compétition et trois épreuves (25m, 50m, 75m) réitérant les mêmes allures intermédiaires que celles du 100-m. VO2 est mesuré avant et juste après chaque épreuve, pendant 1min, par rétro-extrapolation. Les valeurs de VO2 mesurées à la fin des épreuves de 25m, 50m, 75m et 100m permettent de reconstruire la cinétique de VO2 d'une épreuve de 100-m. Les résultats contrastent avec les estimations des cinétiques de VO2 publiées précédemment : VO2 augmente plus vite dans la première moitié de l'épreuve (à 50m, VO2 ≈ 94%VO2max), atteint 100 %VO2max au 75ème mètre de l'épreuve puis chute de 7% sur le dernier 25-m. Une estimation de la contribution relative du métabolisme aérobie montre également des valeurs plus importantes que celles publiées jusqu'à ce jour, du fait de l'atteinte précoce de VO2max en cours d'épreuve. / The bioenergetic model proposed by P.E. di PRAMPERO explains performance in most human locomotions (running, cycling, swimming, ...) using indexes of metabolic power and energy cost of locomotion. Nevertheless, for 100-m front crawl events, environmental conditions make the aerobic power measurement difficult. The main purpose of this thesis is therefore to propose a new procedure to estimate aerobic responses during a 100-m front crawl event, performed in competition conditions. Trained swimmers participated to this study. In a 25-m swimming pool, the procedure includes a 100-m front crawl performance in competition conditions, and then, three tests (25-m, 50-m, 75-m) following the pacing strategy of the 100-m event. VO2 is not measured during the tests, but before and just at the end of each test with a breath-by-breath method. Each post-test VO2 (after 25m, 50m, 75m and 100m) allows to reconstruct the VO2 kinetics of the 100-m performance. The results differ from previous studies in that VO2 increases faster in the first half of the race (at 50m, VO2 ± 94%VO2max), reaches VO2max at the 75th meter; then a decrease in VO2 corresponding to 7% of VO2max appears during the last 25m. The estimation of aerobic contribution shows higher values than those previously published, because VO2max is reached very early during the race.

Introduction Performance in cross-country skiing is influenced by the skier’s ability to continuously produce propelling forces and force magnitude in relation to the net external forces. A surrogate indicator of the “power supply” in cross-country skiing would be a physiological variable that reflects an important performance-related capability, whereas the body mass itself is an indicator of the “power demand” experienced by the skier. To adequately evaluate an elite skier’s performance capability, it is essential to establish the optimal ratio between the physiological variable and body mass. The overall aim of this doctoral thesis was to investigate the importance of body-mass exponent optimization for the evaluation of performance capability in cross-country skiing. Methods In total, 83 elite cross-country skiers (56 men and 27 women) volunteered to participate in the four studies. The physiological variables of maximal oxygen uptake (V̇O2max) and oxygen uptake corresponding to a blood-lactate concentration of 4 mmol∙l-1 (V̇O2obla) were determined while treadmill roller skiing using the diagonal-stride technique; mean oxygen uptake (V̇O2dp) and upper-body power output (Ẇ) were determined during double-poling tests using a ski-ergometer. Competitive performance data for elite male skiers were collected from two 15-km classical-technique skiing competitions and a 1.25-km sprint prologue; additionally, a 2-km double-poling roller-skiing time trial using the double-poling technique was used as an indicator of upper-body performance capability among elite male and female junior skiers. Power-function modelling was used to explain the race and time-trial speeds based on the physiological variables and body mass. Results The optimal V̇O2max-to-mass ratios to explain 15-km race speed were V̇O2max divided by body mass raised to the 0.48 and 0.53 power, and these models explained 68% and 69% of the variance in mean skiing speed, respectively; moreover, the 95% confidence intervals (CI) for the body-mass exponents did not include either 0 or 1. For the modelling of race speed in the sprint prologue, body mass failed to contribute to the models based on V̇O2max, V̇O2obla, and V̇O2dp. The upper-body power output-to-body mass ratio that optimally explained time-trial speed was Ẇ ∙ m-0.57 and the model explained 63% of the variance in speed. Conclusions The results in this thesis suggest that V̇O2max divided by the square root of body mass should be used as an indicator of performance in 15-km classical-technique races among elite male skiers rather than the absolute or simple ratio-standard scaled expression. To optimally explain an elite male skier’s performance capability in sprint prologues, power-function models based on oxygen-uptake variables expressed absolutely are recommended. Moreover, to evaluate elite junior skiers’ performance capabilities in 2-km double-poling roller-skiing time trials, it is recommended that Ẇ divided by the square root of body mass should be used rather than absolute or simple ratio-standard scaled expression of power output. / <p>Incorrect ISBN in printed thesis: 973-91-7601-270-3</p>