The purpose of this study was to investigate the effects of acute moderate hypoxia (14.5% inspired oxygen fraction) on the magnitude of fatigue development during the different phases (work, recovery, and both) of a repeated-sprint test (10 x 6-s sprints interspersed with 30-s recovery) in healthy, trained males. This study also sought to investigate the relationship between anaerobic power reserve and fatigue during the aforementioned repeated-sprint test. Fourteen exercise-trained males completed four trials of the repeated-sprint test under each of the following conditions: (a) normoxia (20.93% inspired oxygen fraction), (b) acute hypoxia during the work intervals only, (c) acute hypoxia during the recovery intervals only, and (d) acute hypoxia during both the work and recovery intervals. The order of the experimental conditions was systematically balanced. Fatigue scores were not different between experimental conditions, despite the fact that arterial oxygen saturation values from the acute hypoxia during recovery condition and the acute hypoxia during both work and recovery condition differed significantly from the normoxia and acute hypoxia during work intervals only conditions (p < .001). There was no relationship between anaerobic power reserve and fatigue in any experimental condition. The results of the present study indicate that although the participants experienced different levels of hypoxia during the experimental trials, the degree of hypoxia was insufficient to alter mechanical performance during a repeated-sprint test. The lack of an effect on mechanical performance does not appear to be influenced by an individual's anaerobic power reserve. It may be inferred that the degree of hypoxia employed was neither severe enough as to impair levels of muscle oxygenation beyond what was experienced in normoxia, nor as to induce further fatigue related to central mechanisms. / Kinesiology

Background: Small-sided games are frequently used as a training method in today´s football. The importance of the ability to perform high-intensity running is increasing and small-sided games may not lead to the required improvement of this ability. It might be necessary to add speed-endurance training to obtain the high-intensity running. Objective: The aim of this study was to investigate which of the training methods; small-sided games or speed-endurance training, leads to the highest performance improvements in three football-specific tests. Measures and Methods: The study was an intervention study where 31 male football players participated. They were randomized in to two groups which performed either speed-endurance training (SEP) (n=16) or small-sided games (SSG) 6 vs 6 (n=15). The study lasted four weeks and eleven sessions in total. Baseline tests and posttraining test were conducted in Yo-Yo IR2, Arrowhead agility test and Repeated sprint 30 meters. Result: SEP demonstrated an 17 % higher increase in testresults than SSG in Yo-Yo IR2. No significant difference between the groups were observed in the other tests. Conclusion: Small-sided games is a training method which entails football-specific training load. It might be necessary to add speed-endurance training which can lead to higher performance improvments in Yo-Yo IR2.

It has been shown that a high level of aerobic fitness is important for athletes participating in intermittent (team) sports. The majority of studies investigating the effects of traditional and sport-specific aerobic interval exercise on physiological measures and performance have involved field-based team sports. In some instances the effectiveness of sport-specific aerobic training has been questioned. To date, no study has investigated the influence of a sport-specific training approach in the sport of basketball. Purpose: The aim of the present study was to evaluate the effectiveness of a basketball specific endurance circuit on improving measures of aerobic fitness. Methods: Ten male high school basketball players, age 16.4 ± 1.2 years, ranked by fitness level and randomly assigned to a training group (N = 6) or control group (N = 4) participated in the study. The sport-specific aerobic endurance training replaced the fitness component of regular training and was performed during the competitive season. The sport-specific training consisted of interval training using a basketball specific endurance circuit, four times 4 min at 90-95% HRpeak with a 3 min recovery at 60-70% HRpeak, twice per week for 6 weeks. During this time the control group performed regular basketball training. Results: For both the training and control groups the actual mean training intensity for total training duration were 77.4 ± 2.9% HRpeak and 74.1 ± 6.7% HRpeak, respectively. The actual mean training intensity during the work intervals in the training group was 84.1 ± 2.3% HRpeak. There were no clear differences between effects of the two training approaches for measures of maximal oxygen uptake (3.3%; 90% confidence limits, ± 19.3%), running economy (-3.3%; 90% confidence limits, ± 14.2%), repeated sprint ability (0.6%; 90% confidence limits, ± 5.7%) and anaerobic power maintenance during the repeated sprints (-13.7%; 90% confidence limits, ± 49.0%). However, a clear non-trivial effect on sub-maximal heart rate was observed (-7.3%; 90% confidence limits, ± 2.0%) suggesting a beneficial training effect after training. Some evidence for attenuation of speed (-1.8 to -2.8%; 90% confidence limits, ± 3.4 to 5.7%) and power (-1.7%; 90% confidence limits, ± 17.1%) was apparent. Conclusion: Although clear changes in sub-maximal HR responses were observed in the training group, the data in the present study suggests that a basketball specific endurance circuit has little effect on other laboratory and field-based measures of aerobic fitness. In fact, the basketball specific endurance circuit may lead to reduced improvements in jumping and sprinting performances. Further research is required to clarify the effect of aerobic training approaches on basketball-specific fitness and performance.

Background: Several field-based team sports contain repeated, maximal effort sprints with varying rest lengths in between. This puts high demands on athletes’ metabolic and neuromuscular systems. Testing the anaerobic capacity of athletes is essential to improve and evaluate the progression. One test being utilised for assessing anaerobic capacity is the 300-yard shuttle run test. The test is field-based with stopwatches as the sole equipment. However, the test has not been properly tested for reliability.   Aim: The aim of this bachelor thesis was therefore to investigate the reliability of the 300-yard shuttle run test. Methods: The study was performed with a test-retest method and included a familiarisation meeting, test session and retest session.  Test subjects performed the 300-yard shuttle run test at two different occasions with seven or fourteen days in between. The intraclass correlation coefficient (ICC) and 95% confidence interval (CI) was utilised to quantify the reliability. An ICC>0.8 was considered acceptable. Results: 17 American football players participated in the study (median age 20, min. =18, max. =38 y; median weight 83, min. =67, max. =133 kg; median height 184, min. =169, max. =194 cm). The ICC for the test-retest was 0.97 (95% CI  0.91-0.99). Conclusion: Based on the results of this study 300-yard shuttle test is proposed as a test providing reliable results.

It has been shown that a high level of aerobic fitness is important for athletes participating in intermittent (team) sports. The majority of studies investigating the effects of traditional and sport-specific aerobic interval exercise on physiological measures and performance have involved field-based team sports. In some instances the effectiveness of sport-specific aerobic training has been questioned. To date, no study has investigated the influence of a sport-specific training approach in the sport of basketball. Purpose: The aim of the present study was to evaluate the effectiveness of a basketball specific endurance circuit on improving measures of aerobic fitness. Methods: Ten male high school basketball players, age 16.4 ± 1.2 years, ranked by fitness level and randomly assigned to a training group (N = 6) or control group (N = 4) participated in the study. The sport-specific aerobic endurance training replaced the fitness component of regular training and was performed during the competitive season. The sport-specific training consisted of interval training using a basketball specific endurance circuit, four times 4 min at 90-95% HRpeak with a 3 min recovery at 60-70% HRpeak, twice per week for 6 weeks. During this time the control group performed regular basketball training. Results: For both the training and control groups the actual mean training intensity for total training duration were 77.4 ± 2.9% HRpeak and 74.1 ± 6.7% HRpeak, respectively. The actual mean training intensity during the work intervals in the training group was 84.1 ± 2.3% HRpeak. There were no clear differences between effects of the two training approaches for measures of maximal oxygen uptake (3.3%; 90% confidence limits, ± 19.3%), running economy (-3.3%; 90% confidence limits, ± 14.2%), repeated sprint ability (0.6%; 90% confidence limits, ± 5.7%) and anaerobic power maintenance during the repeated sprints (-13.7%; 90% confidence limits, ± 49.0%). However, a clear non-trivial effect on sub-maximal heart rate was observed (-7.3%; 90% confidence limits, ± 2.0%) suggesting a beneficial training effect after training. Some evidence for attenuation of speed (-1.8 to -2.8%; 90% confidence limits, ± 3.4 to 5.7%) and power (-1.7%; 90% confidence limits, ± 17.1%) was apparent. Conclusion: Although clear changes in sub-maximal HR responses were observed in the training group, the data in the present study suggests that a basketball specific endurance circuit has little effect on other laboratory and field-based measures of aerobic fitness. In fact, the basketball specific endurance circuit may lead to reduced improvements in jumping and sprinting performances. Further research is required to clarify the effect of aerobic training approaches on basketball-specific fitness and performance.

Background: Repeated sprint training in hypoxia has shown to be superior to training in normoxia. However, both natural and simulated altitude training are strategies that are not always accessible and expensive due to traveling or the need for advanced equipment. A possible way of simulating hypoxic conditions is to administer carbon monoxide (CO) prior to training as it has been shown to reduce the oxygen transport and delivery to the muscle similar to systemic hypoxia. It is therefore hypothesized that inhaling a small bolus of CO prior to repeated-sprint exercise will potentiate the acute physiological responses during the training, thus induce performance improvements associated with repeated sprint ability compared to placebo control. Methods: 23 endurance-trained individuals (18 men and 5 women), age 33.2 ± 6.9 years, body mass 78.3 ± 11.0 kg, height 180.7 ± 7.3 cm, performed a 3-week supervised repeated sprint exercise protocol on electromagnetically braked cycle ergometers. A repeated sprint ability test was conducted pre-and post-training intervention. Participants were randomly assigned to either inhaling CO (INCO group) or inhaling a sham gas (NOCO group). Analysis of covariance (ANCOVA) was conducted to determine statistical significance by controlling for pre-test values. Results: Periodic inhalation of CO prior to repeated sprint exercise led a medium, significant difference in mean power decrement (INCO -2.63%, NOCO 8%; p <0.05, ηp2 = 0.19) and fatigue index (INCO 0.28%, NOCO 8.2%; p <0.05, ηp2 = 0.24) compared to sham gas, despite that both groups increased in number of sprints (INCO 16.58%, NOCO 27.60%; p <0.05; ηp2 = 0.71) with no difference between groups. Conclusion: Our findings in this study showed a positive effect on an improved ability to sustain power output during repeated sprints when periodic inhalation of CO is administered. Therefore, it is suggested that periodic inhalation of CO prior to repeated sprint exercise might be a nuanced way to induce favorable physiological adaptations, thus improving performance associated with repeated sprint ability.

The critical power (CP) concept has been used to determine the appropriate rest interval during intermittent exercise through the investigation of critical rest interval (CRI). Repeated sprint ability (RSA) testing has been developed to define the athlete’s ability to recover and maintain maximal effort during successive bouts. The CP model has been used to understand the physiological responses involved with intermittent exercise delineating between severe and heavy exercise intensity domains. The primary purpose of this study was to determine the CRI from the work-time relationship given by RSA testing using varying work to rest ratios. The secondary purpose was to determine the validity of CRI by evaluation of physiological responses above and below estimated rest interval values during intermittent cycling. Twelve recreationally trained males (mean ± SD; age 24.1 ± 3.6yr; height 175.8 ± 7.0cm; weight 77.6 ± 12.8kg; V̇ O2peak 43.3 ± 5.6ml/kg/min; Body Fat (%) 24.5 ± 4.4) were recruited for this study. Participants performed a graded exercise test to determine V̇ O2peak and peak heart rate. Eight participants completed the same three RSA protocols with 6s maximal sprints and varying rest intervals (12-24s) on a cycle ergometer. Intermittent critical power (ICP) was calculated through the linear total work (TW) and time-to-exhaustion (TTE) relationship, whereas CRI was estimated using the average work per sprint and ICP. Seven subjects completed trials above and below estimated CRI to evaluate the validity of this estimate through the examination of the physiological responses. Breath-by-breath oxygen consumption (V̇ O2) and heart rate (HR) values were recorded during the validation trials. One-way repeated measures analysis of variance (ANOVA) was used to analyze the variables from the RSA trials. Paired samples t-tests were performed to compare performance and physiological variables above or below CRI during the validation trials. Two-way repeated measures ANOVA was used to examined the changes in oxygen consumption (V̇ O2), HR, mean power (MP), and TW throughout the validation trials. Significant differences (p < 0.1) were found for the number of intervals completed, TTE, average work per sprint, peak and mean V̇ O2 between RSA protocols. Linearity between TW and TTE was r2 = 0.952 ± 0.081. During the validation trials, TTE was significantly greater in the above versus the below CRI trial (2270.43 ± 941.15s vs. 1511.00 ± 811.0s). Furthermore, blood lactate concentration (8.94 ± 4.89mmol/L vs. 6.56 ± 3.45mmol/L), AveV̇ O2 (2.05 ± 0.36L/min vs. 1.78 ± 0.26L/min), V̇ O2peak (2.84 ± 0.48L/min vs. 2.61 ± 0.43L/min), and AveHR (151.14 ± 18.46bpm vs. 138.14 ± 17.51L/min) were significantly greater in the below CRI trial when compared to the above CRI trial. Significant interactions were found between above and below trials within minimal V̇ O2 response (F = 6.886, p = 0.024, η2 = 0.534) to the recovery intervals and maximal HR (F = 4.51, p = 0.016, η2 = 0.429) response to the work intervals. During the above CRI trial, minimal V̇ O2 response decreased over time (51-43%V̇ O2 peak) while maximal HR response achieved a steady state level (81-84%HRpeak). Conversely, minimal V̇ O2 response during the below CRI trial achieved a steady state level (54-58%V̇ O2 peak), whereas maximal HR response increased over time (84-90%HRpeak). The relationship between TW and TTE is appropriate for use with RSA testing with varying rest intervals. The differing physiological response during the validation trials may reflect changes in energy system contribution. In conclusion, CRI distinguished between physiological responses related to exercise intensity domains in a manner similar to CP estimates determined from other testing and exercise modalities.

Le rugby à XV est un sport collectif qui se caractérise en match par des courses et des collisions de hauteintensité très variables selon les positions. La première partie des travaux, qui s’est centrée sur l’analyse del’activité par centrale d’analyse cinématique, a mis en évidence une activité de haute intensité plus importante enCoupe d’Europe qu’en TOP14 qui varie selon les cinq postes de jeu en termes de répétitions d’efforts et dedistances parcourues à haute intensité notamment chez les avants. De plus, ces activités de haute intensitédiminuent en première et deuxième mi-temps et sont différentes selon les positions. En effet, une diminution plusprécoce est observée chez les avants et les trois-quarts ailes, qui est majorée au niveau des accélérations entre lesdeux dernières périodes d’un match pour les avants démontrant un impact de la fatigue. A l’inverse, les arrièresarrivent globalement à maintenir une intensité élevée. Ainsi, au regard des résultats de la première partie, ladeuxième partie des travaux a consisté en la mise en place d’un entraînement par répétition de sprints en hypoxieinduite par hypoventilation à bas volume pulmonaire. Celui-ci a permis une amélioration significative de lacapacité à répéter des sprints après sept séances d’entraînement par hypoventilation chez les joueurs très entraînés,alors qu’aucun changement n’a été observé dans le groupe normoxie. L’entraînement en rugby à XV se caractérisepar la répétition d’efforts de haute intensité à dominante dynamique (courses) et statique (musculation, phases decombat) qui vont impacter le remodelage du ventricule gauche de manière spécifique. La troisième partie a montré,à partir d’échocardiographies de repos en mode 2D-strain, une hypertrophie physiologique majorée chez les avantscomparativement aux arrières. Cette hypertrophie s’accompagne d’une augmentation des pressions de remplissageet une diminution de la relaxation lors de la diastole, notamment chez les avants. Enfin, malgré une torsionventriculaire inchangée, les rotations et les vitesses de rotation sont plus grandes au niveau basal et plus faibles auniveau apical chez les joueurs de rugby à XV. Ainsi, cette thèse CIFRE apporte de nouvelles données au niveaude l’analyse de l’activité, des méthodes d’entraînement facilement applicables pour l’entraîneur, ainsi que desdonnées plus spécifiques à l’évaluation cardiaque de repos pour le clinicien. / Rugby union is a team sport characterized by high-intensity collisions and running efforts during gameswhich are position-dependent. Accounting for the five different positional groups, the first part of this thesisdemonstrated greater high-intensity activity in European cup when compared to the TOP14 rugby unioncompetition; with position-dependent variations in the frequency of repeated high-intensity efforts and the relativedistance of high-speed movements in forwards. A decrease in high-intensity movement parameters was observedduring the first and second halves of a competitive rugby union match. Indeed, the decrease in high-intensitymovements was earlier in forwards and outside backs who peaked in high-intensity accelerations between the lasttwo periods of the game, while backs were able to maintain their high-intensity activity throughout the match.Collectively, the capacity for a player to repeat high-intensity efforts during a rugby union game varied by thelevel of competition and was influenced by the onset of fatigue. In this context, the second part of this thesis was to conduct a repeated-sprint training in hypoxia. Hypoxia was induced by voluntary hypoventilation at low lungvolume. This training protocol has largely improved the repeated-sprint ability performance in highly-trainedrugby union players after seven training sessions of hypoventilation, whereas it was unaltered in the controlnormoxic group. Such training demands in rugby union (characterised by repeated high-intensity efforts indynamic (running) and static (weightlifting, fighting)) have a specific impact on left ventricular remodelling. Thelast part of this thesis, using 2D-speckle-tracking resting echocardiography, demonstrated that LV hypertrophywas greater in forwards when compared to backs and to control group. Systolic function remained unchanged, butdiastolic function was altered, mainly in forwards, with an increase in filling pressures and a decrease in leftventricular relaxation. Finally, left ventricular twisting was similar while rugby union players exhibited lowerapical and higher basal rotations velocities compared to controls. Collectively, this CIFRE research programprovided new data in activity analysis and training methods that are widely applicable to a range of rugby unionprograms and data on left ventricular morphology, function and mechanics for the clinician.

Bakgrund: För att prestera på elitnivå behöver Fotbollsspelare en välutvecklad aerob och anaerob effekt och kapacitet. Repeated sprint ability (RSA) är en anaerob förmåga som kan avgöra många matchsituationer, till exempel bollinnehav och målchanser. För att testa RSA görs ett repeated sprint ability test (RST). Syreupptagningsförmågan testas ofta genom olika konditionstester. Syftet med denna studie var att undersöka korrelationen mellan RST, Yo-Yo Intermittent Recovery Level 1 test (Yo-Yo IR1) och 30-15 Intermittent Fitness Test (30-15IFT). Metod: Nio damfotbollsspelare som randomiserades in i två grupper (Grupp 1, n=5, 22±3 år, kroppsvikt 64±12,8 kg och grupp 2, n=4, 20±3 år, kroppsvikt 64,2±2,4 kg). Deltagarna genomförde antingen RST och/eller Yo-Yo IR1 vid ett tillfälle och vid nästa tillfälle RST och/eller 30-15IFT. Alla tester skedde utomhus på en konstgräsplan. På Yo-Yo IR1 och 30-15IFT dokumenterades sluthastigheten. På RST dokumenterades den totala sprinttiden (RSTtotal) och %trötthet mellan bästa sprinten jämfört med resterande sprinter (RST%dec). Resultatet på testerna presenteras som en grupp i medelvärde och standardavvikelse (SD). Uträkningen av korrelationen användes Pearsons Korrelationskoefficient (r). Statistisk nivå för signifikans var p &lt;0.05. Resultat: Korrelationen mellan Yo-Yo IR1 mot 30-15IFT samt 30-15IFT mot RSTtotal hade en väldigt stark statistiskt signifikant korrelation (r = 0.855; respektive r= -0.721). Det fanns inte någon statistiskt signifikant korrelation mellan Yo-Yo IR1 mot RSTtotal, IRL mot RST%dec, och 30-15IFT mot RST%dec (r= -0.704; r=0.209 respektive r=-0.02). Konklusion: Resultaten indikerar att det finns en väldigt stark korrelation mellan Yo-Yo IR1 och 30-15IFT och fördelar mot nackdelar bör vägas för att använda vilket test. 30-15IFT verkar använda en högre andel RSA eftersom det hade en starkare korrelation till RST än Yo-Yo IR1.