Das maximale Laktat-steady-state (MLSS) gilt als ein physiologischer Parameter der Ausdauerleistungsfähigkeit. Bereits in den 1980er Jahren entwickelte Mader (1984) auf Basis der Michaelis-Menten-Kinetik eine Berechnungsmethode zur Bestimmung der Leistung im MLSS. Diese Methode setzt die Kenntnis der maximalen Reaktionsgeschwindigkeiten von Glykolyse und Atmung voraus. Die Goldstandard-Methode zur Ermittlung der Leistung im MLSS sind mehrere 30-minütige konstante Dauerbelastungen. Das hauptsächliche Ziel der vorliegenden Arbeit bestand in dem Vergleich der berechneten mit der empirisch ermittelten Leistung im MLSS. 57 männliche Probanden unterzogen sich zunächst in randomisierter Reihenfolge einem Test zur Bestimmung der maximalen Laktatbildungsrate sowie der maximalen Sauerstoffaufnahme. Im Anschluss absolvierten die Testpersonen mehrere 30 minütige Dauertests zur empirischen Ermittlung der Leistung im MLSS. Die ermittelten Ergebnisse zeigen, dass zwischen beiden Testmethoden eine hochsignifikante Korrelation (r = 0,89; p< 0,001) sowie eine mittlere Differenz von -13 Watt vorliegt. Ausgehend von den ermittelten Ergebnissen kann der Schluss gezogen werden, dass die Leistung im MLSS, ermittelt unter Verwendung der Methode nach Mader (1984) im Mittel mit der empirisch ermittelten Leistung im MLSS sehr gut übereinstimmt. Neben der angeführten Hauptstudie, wurde in der vorliegenden Arbeit weiterhin die Reliabilität und Tag-zu-Tag-Variabilität der Leistung im MLSS, der Einfluss der Testdauer auf die Laktatbildungsrate sowie die Praktikabilität der berechneten Leistung im MLSS in einem Einzelzeitfahren näher untersucht.

Lactate is an important biomarker in sports and the lactate threshold concept is one of the best indicators of endurance performance in an athlete. However, to quantify the lactate threshold, an invasive method to take a blood sample must be used. Limitations for this method include stopping the active exercise for blood sampling and no real-time feedback. Instead, a novel non-invasive wearable biosensor can be used to measure the lactate concentration in sweat. The sensor generates an electrical current depending on the lactate concentration in the sweat, and therefore must an electronic device called a potentiostat be used to condition the current. However, available potentiostats are not suitable for use in sports where form factor, battery life and wireless connectivity is important. This thesis aims to solve this by developing a wearable device and software which can be used to measure the lactate concentration in sweat in real-time during exercise. The development process consisted of the determination of specifications, prototype development and thorough laboratory and on-body testing. Finally, a novel wearable device and software capable of real-time lactate measurements in sweat during exercise were presented. The device, called LactateStat, was 58mm ∗ 55mm ∗ 13mm, the current consumption was only 7.8mA, the current measurement resolution was 0.5 nA, the limit of detection was 0.45 nA and the current measurement range was around 750 μA. LactateStat is one of the first of its kind and provides a base for future development as the hardware, firmware and software resources are provided as open-source. / Laktat är en viktig biomarkör inom idrott och konceptet laktattröskel är en av de bästa indikatorerna för uthållighet hos en idrottsutövare. Men för att mäta laktattröskeln krävs en invasiv metod som går ut på att man tar ett blodprov. Begränsningarna med denna metod är bland annat att idrottsutövningen måste stoppas för att ta ett blodprov och att man inte får realtidsåterkoppling. I stället kan en liten och icke-invasiv bärbar biosensor användas för att mäta laktatkoncentrationen i svett. Sensorn genererar en elektrisk ström beroende på laktatkoncentrationen i svetten och en enhet som kallas potentiostat måste därför användas för att mäta denna ström. Tillgängliga potentiostater är dock inte lämpliga för användning inom sport där formfaktor, batteritid och trådlös kommunikation är viktigt. Denna avhandling har som syfte att lösa detta genom att utveckla en bärbar enhet och mjukvara som kan användas för att mäta laktatkoncentrationen i svett i realtid under träning. Utvecklingsprocessen bestod av bestämning av specifikationer, framtagning av en prototyp och noggrann laboratorie- och kroppstestning. Som resultat presenterades en banbrytande bärbar enhet och mjukvara som kan mäta laktat i realtid i svett under träning. Enheten, som kallades LactateStat, var 58mm * 55mm * 13mm, den aktiva strömförbrukningen var 7.8mA, den bästa mätupplösningen för ström var 0.5 nA, detektionsgränsen var 0.45 nA och det maximala mätområdet för ström var ca. 750 μA. LactateStat är en av de första i sitt slag och ger en bas för framtida utvecklingsarbete eftersom hårdvaru-, programvaru- och mjukvaruresurserna tillhandahålls som öppen källkod.

Aim The aim for this present study was to investigate the acute metabolic response from intermittent resistance exercise during hypoxia, with the following research questions: (1) Are blood levels of lactate and glucose different between hypoxia and normoxia? (2) Does hypoxia induce higher lactate accumulation and pH reduction in the human skeletal muscle? (3) Is there a relationship between plasma-, blood- and muscle lactate? Method Eight healthy males (30 ± 2 years) performed 6 sets of unilateral leg extension on each leg (75% of 1RM) with randomized normoxic (20,9% inspired 𝑂2) and normobaric hypoxic (12% inspired 𝑂2) conditions. A total of 5 muscle biopsies was extracted from m. Vastus Lateralis (pre-, post exercise, 90-, 180min and 24h post exercise) during both normoxia and hypoxia trials, separated by one week for all participants. Blood samples were repeatedly taken with 20 min intervals. Heart Rate (HR) and saturation (𝑆𝑝𝑂2) were measured by a pulsoximeter during resistance exercise. Results No significant main effect was observed for blood lactate and glucose levels as well as the muscle lactate accumulation and pH between normoxia and hypoxia. However, pH in muscle showed a trend between the conditions post exercise where hypoxia reached lower levels in total (P=0.08). Significant correlations were observed for blood- and plasma lactate, where hypoxia showed a stronger relationship than normoxia (r=0.98 compared to r=0.87). Equal findings for the correlation of muscle- and plasma lactate showed an even greater coefficient value for hypoxia compared to normoxia (r=0.860 compared to r=0.59). Conclusion Summarized data indicated that no significant difference between hypoxia and normoxia was evident. Nonetheless, tendencies illustrate that hypoxia may alter the metabolic response slightly. However, further research is needed to draw a conclusion between the conditions. / Syftet med denna studie är att undersöka kroppens akuta metabola svar från intermittent styrketräning under hypoxi, med följande frågeställningar: (1) Skiljer sig nivåerna av laktat och glukos i blodet mellan hypoxi och normoxi? (2) Skapar hypoxi större laktatansamling och pH reduktion i människoskelettmuskeln? (3) Finns det en relation mellan plasma-, blod- och muskellaktat? Metod Åtta friska män (30 ± 2 år) deltog där deltagarna utförde 6 set unilateral benextension för varje ben (75% 1RM). Intermittent styrketräning randomiserades med hypoxi som utfördes med 12% syrgas och normoxi som bibehöll normal syrgasnivå (20,9% syrgas). Under två testdagar togs 5 muskelbiopsier från m. Vastus Lateralis (före-, efter träning, 90-, 180min och 24h efter träning) på vartannat ben per testdag. Hjärtfrekvensen och 𝑆𝑝𝑂2 mättes via pulsoximeter under träningen. Resultat Ingen signifikant huvudeffekt påvisades mellan hypoxi och normoxi för blodlaktat samt glukos, såväl som laktatackumulationen och pH värdet i muskeln. Muskel pH visade en trend där hypoxi efter styrketräning nådde lägre totalnivå än normoxi (P=0,08). Vidare observerades hypoxi att ha starka relationer mellan blod- och plasmalaktat jämfört med normoxi (r=0,98 vs. r=0,87). Större skillnad framgick för korrelationen mellan muskel- och plasmalaktat där hypoxi-försöket utgav starkare koefficient jämfört med normoxi (r=0,86 vs. r=0,59). Konklusion Sammanfattad data visar att hypoxi inte skapar större metabolisk respons vid intermittent styrketräning. Trots detta framkom tendenser som illustrerar att hypoxi kan påverka den metabola stressen under styrketräning. Däremot krävs vidare forskning för att kunna säkerställa effekten av hypoxi på kroppens metabola svar. / Ingår i Marcus Mobergs projekt: ”Resistance exercise under hypoxia and the acute molecular effects in human skeletal muscle

Die genaue physiologische Funktion des zellulären Prion-Proteins (PrPC) ist noch immer nicht vollständig verstanden. Eine mögliche Funktion des PrPC auf das neuronale Überleben nach einem hypoxischen oder ischämischen Insult wird diskutiert. In einem Vorversuch zeigten sich nach zerebraler Ischämie deutlich größere Infarktvolumina in den Gehirnen von Prion-Knock-Out-Mäusen im Vergleich zu denen der Wild-Typ-Mäuse. Das Identifizieren der molekularen Mechanismen der PrPC-vermittelten Neuroprotektion ist daher von großem Interesse und machte die Etablierung eines Zell-Modells erforderlich. Neuere Studien konnten einen Einfluss des zellulären Prion-Proteins auf die Glykolyse nachweisen. Unter Sauerstoffmangelbedingungen kommt es zu einer vermehrten Bildung von Laktat durch das Enzym Laktat-Dehydrogenase (LDH). Neurone benötigen unter hypoxischen oder ischämischen Bedingungen dieses Laktat als Energiesubstrat. Je mehr Laktat den Neuronen zur Verfügung steht, umso höher ist das neuronale Überleben. In dieser Arbeit konnte die Beteiligung der Laktat-Dehydrogenase an der durch das zelluläre Prion-Protein vermittelten Neuroprotektion nach Hypoxie nachgewiesen werden. Das Ziel dieser Arbeit bestand darin, mögliche Unterschiede der LDH-Expression in WT-Zellen, Prnp0/0-Zellen und HEK-293-Zellen unter normalen und hypoxischen Bedingungen in vitro zu untersuchen. Die Expression der LDH war unter hypoxischen Bedingungen in den WT-Zellen im Vergleich zu den Prnp0/0-Zellen deutlich höher. Dies konnte auch in PrPC-überexprimierenden HEK-293-Zellen nach Hypoxie gezeigt werden. Ebenso konnte nachgewiesen werden, dass Hypoxie zu einem größeren Schaden des Tubulinzytoskelettes in Prnp0/0-Zellen führt als in WT-Zellen, was eine neuroprotektive Wirkung von PrPC vermuten lässt. Eine direkte oder indirekte Interaktion von LDH-A und PrPC konnte durch eine Co-Immunpräzipitation in HEK-293-Zellen nachgewiesen werden. Die genauen Mechanismen über die PrPC möglicherweise zu einer vermehrten Laktat-Produktion führt, sind noch nicht eindeutig identifiziert und müssen noch näher untersucht werden. Zusammengefasst kann gesagt werden, dass die erhobenen Daten die Vermutung verstärken, dass das Enzym LDH und sein Produkt Laktat in die durch das zelluläre Prion-Protein vermittelte Neuroprotektion nach Hypoxie involviert sind. Es ist das erste Mal, dass gezeigt wurde, durch welchen Mechanismus PrPC zur Neuroprotektion beiträgt.

<p>Kardijalni biomarkeri u predviđanju operativnog rizika kardiohirur&scaron;kih bolesnika sa oslabljenom sistolnom funkcijom leve komore Evaluacija rezultata u kardiohirurgiji podrazumeva praćenje ishoda operativnog lečenja u određenom vremenskom periodu. Najče&scaron;će je to interval od 30 dana od datuma intervencije. Najče&scaron;ći kriterijumi za praćenje su stopa mortaliteta i morbiditeta, dužina boravka u jedinici intenzivnog lečenja, ukupna dužina hospitalizacije i tro&scaron;kovi lečenja. Stratifikacija rizika podrazumeva da se bolesnici mogu podeliti u grupe u zavisnosti od broja i važnosti preoperativno utvrđenih faktora rizika, odnosno da se pre operacije može predvideti ishod hirur&scaron;ke intervencije kod svakog od njih pojedinačno. U Evropi je, u periodu između 1995. i 1999. godine, na osnovu multicentrične studije u 8 evropskih zemalja i 128 kardiohirur&scaron;kih centara u kojima je operisano 19.030 odraslih bolesnika, kreiran EvroSKOR - EuroSCORE (European System for Cardiac Operative Risk Evaluation) model za stratifikaciju rizika u kardiohirurgiji. Međutim, neminovne promene i napredak u operativnom lečenju doveli su do toga da je neophodno ažurirati postojeći sistem stratifikacije. Tako je 2012. godine u rutinsku upotrebu uveden novi sistem Euroscore II. Na Klinici za kardiohirurgiju Instituta za kardiovaskularne bolesti Vojvodine (IKVBV), EuroSCORE model uveden je u rutinsku upotrebu od početka 2001. godine. Analizom rezultata, posle dvogodi&scaron;nje primene, pokazalo se da je model bio precizan, odnosno da nije postojala značajna razlika između očekivanog (3,7%) i stvarnog mortaliteta (3,47%). U poslednjih nekoliko godina, kod bolesnika kojima sledi kardiohirur&scaron;ka intervencija, u smislu razmatranja njihove prediktivne vrednosti, sve vi&scaron;e pažnje se poklanja kardijalnim biomarkerima. Najznačajniji biomarkeri u kardiovaskularnoj medicini su: Troponin, Kreatin kinaza MB izoenzim (CKMB), N-terminalni pro B-tip natriuretski peptid (NT-proBNP), C-reaktivni protein (CRP), Laktat dehidrogenaza (LDH), Mokraćna kiselina (Acidum uricum). Ciljevi ovog rada su bili da se kreira model za predviđanje preoperativnog rizika kardiohirur&scaron;kih bolesnika sa oslabljenom sistolnom funkcijom leve komore na osnovu preoperativnih vrednosti određenih biomarkera i da se kreira novi model sa kombinacijom prethodnog modela i već postojećeg modela EuroSCORE II. Ispitana su 704 bolesnika sa oslabljenom sistolnom funkcijom leve komore, ejekcione frakcije manje ili jednake 50%. Bolesnici su operisani na Institutu za kardiovaskularne bolesti Vojvodine, od 20. januara 2014. do 20. aprila 2016. Kod bolesnika su urađene tri vrste operacija: revaskularizacija miokarda-koronarna hirurgija, hirurgija stečenih srčanih mana - valvularna hirurgija i kombinovane operacije. Od biohemijskih analiza, 24 sata pre operacije, urađene su sledeće analize: troponin I, kreatin kinaza, kreatin kinaza MB izoenzim, masena kreatin kinaza, laktat dehidrogenaza, C-reaktivni protein, NT-proBNP i mokraćna kiselina. Praćen je postoperativni mortalitet, postoperativni infarkt miokarda i postoperativni cerebrovaskularni incident i njihova povezanost sa preoperativnim vrednostima nabrojanih biomarkera. U studiju su bili uključeni svi bolesnici sa stečenim bolestima srca, stariji od 18 godina, kod kojih je ejekciona frakcija leve komore bila manja ili jednaka 50% i kod kojih su izvr&scaron;ene sledeće vrste operacija: revaskularizacija miokarda - koronarna hirurgija, hirurgija stečenih srčanih mana - valvularna hirurgija i kombinovane operacije - koronarna i valvularna hirurgija. Rezultati su pokazali da je postoperativni mortalitet bio 3,13%, da je postoperativni infarkt miokarda imalo 7,95% a postoperativni cerebrovaskularni incident 9,23% od ukupnog broja ispitanika. 1. Povezanost vrednosti biomarkera sa postoperativnim infarktom miokarda kod bolesnika sa oslabljenom ejekcionom frakcijom leve komore: povi&scaron;ene preoperativne vrednosti troponina I su bile povezane sa postoperativnim infarktom miokarda. Povezanost preoperativnih vrednosti biomarkera sa postoperativnim cerebrovaskularnim incidentom kod bolesnika sa oslabljenom ejekcionom frakcijom leve komore: povi&scaron;ene preoperativne vrednosti troponina I i CRP-a su bile povezane sa postoperativnim cerebrovaskularnim incidentom. 2. Analiziran je uticaj preoperativnog nivoa svih biomarkera, pojedinačno, na značajne neželjene kardijalne i cerebrovaskularne događaje - Major Adverse Cardiac and Cerebrovascular Events (MACCE) kao ishod posle operacije na srcu, kod bolesnika sa oslabljenom ejekcionom frakcijom leve komore. Dobijeni su sledeći rezultati: Preoperativna vrednost nivoa troponina I veća od 0,01&mu;g/L i MACCE bili su povezani. Povećane preoperativne vrednosti nivoa C-reaktivnog proteina (CRP) i postoperativni MACCE bili su povezani. Povećane preoperativne vrednosti nivoa laktat dehidrogenaze (LDH) i MACCE bili su povezani. Zaključci ove teze su: 1. Nezavisni prediktor postoperativnog infarkta miokarda i značajnih neželjenih kardijalnih i cerebrovaskularnih događaja, kod kardiohirur&scaron;kih bolesnika sa oslabljenom sistolnom funkcijom leve komore, ejekcionom frakcijom manjom ili jednakom 50%, jeste povi&scaron;ena preoperativna vrednost troponina I. 2.Vrednost preoperativnog troponina I je slab marker za predviđanje postoperativnog infarkta miokarda i značajnih neželjenih kardijalnih i cerebrovaskularnih događaja, kod kardiohirur&scaron;kih bolesnika sa oslabljenom sistolnom funkcijom leve komore, ejekcionom frakcijom manjom ili jednakom 50%. 3. Na pojavu postoperativnog cerebrovaskularnog incidenta, kod kardiohirur&scaron;kih bolesnika sa oslabljenom sistolnom funkcijom leve komore, ejekcionom frakcijom manjom ili jednakom 50%, ne utiče nijedna od ispitivanih varijabli. 4. Nezavisni prediktori postoperativnog mortaliteta kod kardiohirur&scaron;kih bolesnika sa oslabljenom sistolnom funkcijom leve komore, ejekcionom frakcijom manjom ili jednakom 50%, na osnovu kojih je moguće kreirati prediktivni Model su godine starosti i povi&scaron;ene preoperativne vrednosti NT-proBNP. 5. Kreirani Model je dobar marker za predikciju ishoda posle operacije na srcu, kod kardiohirur&scaron;kih bolesnika sa oslabljenom sistolnom funkcijom leve komore, ejekcionom frakcijom manjom ili jednakom 50%. 6. Povi&scaron;ena preoperativna vrednost NT- proBNP može da bude dobar marker u predikciji smrtnog ishoda posle operacije na srcu kod bolesnika sa oslabljenom sistolnom funkcijom leve komore, ejekcionom frakcijom manjom ili jednakom 50%. 7. Model EuroSCORE II se pokazao kao slabiji marker za predikciju ishoda posle operacije na srcu kod kardiohirur&scaron;kih bolesnika sa oslabljenom sistolnom funkcijom leve komore, ejekcionom frakcijom manjom ili jednakom 50%. 8. Testiranjem kreiranog modela, podelom na manje rizične i vi&scaron;e rizične bolesnike, u odnosu na visinu ejekcione frakcije leve komore, pokazalo se da je model dobar marker za predviđanje smrtnog ishoda posle operacije na srcu, u obe grupe.</p> / <p>Cardiac surgery operative risk assessment in patients with imapired systolic left ventricular function using cardial biomarkers Evaluation of results in cardiac surgery involves monitoring the outcomes of operative treatment in a given time period. Typically, this interval includes 30 days from the date of operation. The most common criteria used for monitoring are the rate of mortality and morbidity, length of stay in the intensive care unit, the total length of hospitalization and medical costs. Risk stratification means that patients can be divided into groups depending on the number and importance of preoperatively identified risk factors, and that the outcome of surgery for each of the patients can be predicted preoperatively. In Europe, in the period of 1995-1999 on the basis of a multi-center study in 8 European countries and 128 cardiac centers in which 19,030 adult patients were operated on, EuroSCORE (European System for Cardiac Operative Risk Evaluation) model for risk stratification in cardiac surgery was developed. However, the inevitable changes and progress in the surgical treatment rendered the EuroSCORE model obsolete warranting updated system. It was in 2012 when a new system EuroSCORE II was introduced into practice At the Clinic for Cardiac Surgery of the Institute of Cardiovascular Diseases, EuroSCORE model was introduced in routine clinical use since the beginning of 2001. By analyzing the results, two years after application, it was shown that the model was accurate, and that there was no significant difference between the expected (3.7%) and the actual mortality (3.47%) In recent years, in patients who are candidates for cardiac surgery, more attention is paid to cardiac biomarkers in terms of evaluating their predictive power. The most significant biomarkers in cardiovascular medicine are: Troponin, creatine kinase MB isoenzyme (CKMB), N-terminal pro B-type natriuretic peptide (NT-proBNP), C-reactive protein (CRP), Lactate dehydrogenase (LDH), and uric acid (Uric uricum). The objectives of this study were to create a model to predict preoperative risk for cardiac surgery patients with impaired systolic left ventricular function on the basis of preoperative levels of certain biomarkers and to create a new model with a combination of the previous model and already existing EuroSCORE II model. The study included 704 patients with impaired systolic left ventricular function, ejection fraction less than or equal to 50%. All patients underwent cardiac surgery at the Institute of Cardiovascular Diseases, from January 20th 2014 until 20th April 2016. Patients were submitted to three types of operations: revascularization - coronary surgery, surgery of acquired heart defects - valvular surgery and combined operations. Following biochemical analyses were performed 24 hours prior to surgery: troponin I, creatine kinase, creatine kinase MB isoenzyme, mass creatine kinase, lactate dehydrogenase, C-reactive protein, NT-proBNP and uric acid. Postoperative mortality, postoperative onset of myocardial infarction and occurence of cerebrovascular accident and their correlation with preoperative values of listed biomarkers were registered. The study included all patients with acquired heart disease, older than 18 years, with the left ventricular ejection fraction less than or equal to 50% who were submitted to the following types of operations: revascularization - coronary surgery, surgery of acquired heart diseases - valvular surgery and combined operations - coronary and valvular surgery. The results showed that the postoperative mortality was 3.13%, new onset of postoperative myocardial infarction was detected in 7.95% of the patients and postoperative cerebrovascular accident developed in 9.23% of patients. Correlation of preoperative biomarkers values with postoperative myocardial infarction in patients with impaired left ventricular ejection fraction - elevated preoperative troponin I were associated with postoperative myocardial infarction. Correlation of preoperative biomarkers values with postoperative cerebrovascular incident occurence in patients with impaired left ventricular ejection fraction - elevated preoperative troponin I and CRP were associated with postoperative cerebrovascular incident. The influence of preoperative levels of all biomarkers, separetly, on the rate of significant adverse cardiac and cerebrovascular events - Major Adverse Cardiac and Cerebrovascular Events (MACCE) as the heart surgery outcome, in patients with impaired left ventricular ejection fraction. The following results were obtained: Increased preoperative levels of C-reactive protein (CRP) and postoperative MACCE were related. Increased preoperative levels of lactate dehydrogenase (LDH) and MACCE were related. The conclusions of this thesis are: 1. Independent predictor of postoperative myocardial infarction onset and significant adverse cardiac and cerebrovascular events in cardiac surgery patients with impaired systolic left ventricular function (ejection fraction less than or equal to 50%) is elevated preoperative value of troponin I. 2. Preoperative Troponin I value was poor marker for predicting postoperative myocardial infarction and significant adverse cardiac and cerebrovascular events in cardiac surgery patients with impaired systolic left ventricular function (ejection fraction less than or equal to 50%). 3. None of the studied variables showed influence on the postoperative cerebrovascular accident occurence, in cardiac surgery patients with impaired systolic left ventricular function (ejection fraction less than or equal to 50%). 4. Independent predictors of postoperative mortality in cardiac surgery patients with impaired systolic left ventricular function (ejection fraction less than or equal to 50%), that could be used to create a predictive model are: age and elevated preoperative value of NT-proBNP. 5. Developed model showed satisfactory results for predicting outcome after heart surgery in cardiac surgery patients with impaired systolic left ventricular function (ejection fraction less than or equal to 50%). 6. Elevated preoperative value of NT-proBNP may be a good marker for mortality prediction after the cardiac surgery in patients with impaired systolic left ventricular function (ejection fraction less than or equal to 50%). 7. EuroSCORE II model showed poor performance when predicting outcomes after cardiac surgery in patients with impaired systolic left ventricular function (ejection fraction less than or equal to 50%). 8. Validation of the newly-created model, considering low and medium risk patients, based on the value of left ventricular ejection fraction, showed that the model is a good marker for the mortality prediction in both groups.</p>

Background: Oral contraceptives are common among female athletes. Still, its effects on athletic performance are poorly investigated. Research in the area has increased in recent years. However, the study qualities and designs are often insufficient and with small sample sizes. Women are currently underrepresented in sport research, and to recruit more women in future studies and to facilitate female athletes’ choices about contraceptives, the impact of oral contraceptives on performance must be better understood. Aim: The aim was to investigate whether monophasic, combined oral contraceptive phases affected maximal muscle strength, anaerobic performance and the corresponding blood lactate response, or perceived mental and physical energy level among young women. Method: The study used a cross-over design where six participants were tested on two occasions. The participants were healthy women between 18 and 29 years old who had beenusing monophasic combined oral contraceptives for at least three months prior to the study. No criteria for training level was set. The Isometric mid-thigh pull (N) was used as an indicator ofmaximal muscle strength; and the Wingate anaerobic test (W) measured anaerobic performance and power with corresponding blood lactate levels (mmol/L) measured at 0, 3 and 5 minutes after termination of the test. The participants rated their current physical and mental energy level on both test occasions using a visual analog scale (0-10). Statistical analyses were madeusing Wilcoxon signed-ranked test. Results: Nine participants were recruited, of which six performed tests on both occasions. The participants had a mean (SD) age of 22.3 (1.8) years, a BMI of 23.3 (2.6) and all reached WHO’sphysical activity recommendations. No statistically significant differences in muscle strengthor anaerobic performance were found regarding peak force (p=0.60), peak power (p=0.35) oraverage power (p=0.60) between oral contraceptive phases. Neither were there any differencesin the blood lactate response to the Wingate test directly after (p=0.92), 3 minutes after (p=0.17) or 5 minutes after (p=0.60) the test. No differences in perceived mental energy level (p=0.35)or perceived physical energy level (p=0.17) between oral contraceptive phases were evident. Conclusion: Oral contraceptive phases did not affect maximal muscle strength, anaerobicperformance, blood lactate response or perceived mental or physical energy levels. Accordingly, there is no need to adapt training to oral contraceptive phases and women can berecruited in future research without consideration of oral contraceptive phases.

In dieser Arbeit wurden die Morpho-Physiologie und das Verhalten zweier Arten Afrikanischer schwach elektrischer Fische, Marcusenius victoriae und Petrocephalus degeni, im Labor und in einem ihrer natürlichen Habitate im Lwamunda Sumpf in Uganda untersucht. Die zwei Hauptziele dieser Arbeit waren (i) tageszeitabhängige Verhaltensrhythmen (Aktivität, Habitatnutzung) im Labor und im Freiland zu untersuchen und (ii) die Ausprägung und Plastizität der morpho-physiologischen Merkmale von P. degeni zu untersuchen, die ihnen erlauben bei natürlich vorkommender, geringer Sauerstoffverfügbarkeit (Hypoxie) zu überleben. Tageszeitabhängige Verhaltensrhythmen beider Arten wurden im Labor über 42 Stunden und im natürlichen Habitat dieser Fische für sechs Tage erfasst. In den Laborversuchen verbrachten beide Arten tagsüber annähernd 100% der Zeit in einem bereitgestellten Versteck und schwammen nachts heraus um aktiv ihre Umwelt zu erkunden. Im Habitat wurden die meisten Fische in strukturell komplexen Habitaten unter schwimmenden Pflanzen detektiert. Nachts schwammen die Fische aktiv in die offenen und ungeschützten Bereiche der Lagune, vermutlich um nach Futter zu suchen und zu interagieren. Die Begleitende in-situ Messung der Sauerstoffverfügbarkeit zeigte, dass beide Arten präsent und vermutlich sogar am aktivsten waren während Phasen extremer nächtlicher Hypoxie. Zur Untersuchung der respiratorischen Merkmale von P. degeni wurden Respirometrieversuche mit hypoxie-akklimatisierten Tieren durchgeführt, Hämoglobin- und Laktatkonzentration im Blut gemessen, und morphologische Parameter an den ersten beiden Kiemenbögen erfasst. Die Fische zeigten niedrige Sauerstoffverbrauchsraten, welche sie bis zu einem sehr niedrigem äußeren Sauerstoffpartialdruck aufrechterhielten. Zusätzlich zeigten sie hohe Hämoglobin- und Laktatkonzentrationen im Blut. Bis zu 75 Tage Normoxie-Akklimatisierung führte zu reduzierter Hämoglobinkonzentration und kürzeren Kiemenfilamenten. / In this thesis, I investigated the morpho-physiology and behavior of two species of African mormyrid weakly electric fish, Marcusenius victoriae and Petrocephalus degeni, in the laboratory and in one of their natural habitats, the Lwamunda Swamp in Uganda. The two main objectives of this work were to (i) observe behavioral rhythms and habitat use patterns of both species under natural and laboratory conditions, and (ii) assess expression and plasticity of morpho-physiological traits that might enable P. degeni to survive naturally occurring low oxygen conditions (hypoxia). Behavioral rhythms were recorded in the laboratory over 42 hours and in the habitat on six sampling days. In the laboratory, both species spent close to 100% of the time in their shelter during the day and actively explore their environment at night. In the swamp lagoon, fish were most often encountered in structurally complex habitats under floating vegetation and ventured into open and unsheltered areas of the lagoon at night, presumably to forage and interact. Concomitant in-situ oxygen measurements revealed that these fish were present, and presumably most active during periods of extreme nocturnal hypoxia in their swamp habitat. To investigate respiratory traits of swamp-dwelling P. degeni, I conducted respirometry experiments and measured blood lactate and hemoglobin and gill morphometrics on the first two gill arches. Fish showed low routine oxygen consumption rates, which they maintained until a very low ambient oxygen partial pressure was reached. Additionally, they had high concentrations of hemoglobin and lactate in their blood. Up to 75 days of normoxia exposure reduced blood hemoglobin and gill filament length.

Aim The main aim of this study was to investigate the longitudinal effects on cycling performance using a polarized and periodized scheme that was highly supervised and controlled. The second aim was to investigate the effect of using Hyperoxia. The questions used to address the aim were: (1) How does overall performance change after a six-week training intervention? (2) What is the time-course and pattern of performance changes to the training scheme? (3) How does the performance change within the groups?   Method Nineteen male and female cyclists started the study (13 male and 6 female), however only 12 completed it (8 male and 4 female). The characteristics for the 12 subjects were:  age (year) 33.6 ± 6.8, height (cm) 177 ± 9.1, body mass (kg) 73.4 ± 8.8. Using a randomized, double blind design, the test subjects were divided in to hyperoxia (HOT) (n = 6) and normoxia (NOT) (n = 6) training groups.  Over a six week period the subjects followed a controlled polarized periodization that included 15 high intensity interval training (HIIT) sessions (3 x 8 min, 3 x 8 + 4 min, 4 x 8 min &amp; 4 x 4 min) on maximal sustainable intensity (isoeffort) on a cycle ergometer. The dosage of oxygen was administered intermittently by the oxelerate device. A 20 min all out test was performed as pre- and post test.    Results The whole group (n = 12) increased mean power output (W) by 6.4 % (P = 0.002). The relative power output (W/kg) increased significantly 8.2 % (P = 0.0011). The HOT group (n = 6) increased their power output by 8.3 % (P = 0.028) and their relative power output increased by 9.4 % (P=0.011). The whole group (P = 12) significantly increased their VO2mean by 4.1 % (P = 0.03) and in the relative value by 5.4 % (P = 0.01) on the 20 min all out test. The whole group also had a significant increase in VO2peak of 3.7 % (P = 0.04). A very strong correlation could be found between the training data and the performance test.   Conclusions The training intervention was favourable for increasing performance and VO2peak in cycling. Usage of hyperoxia during the training intervention increases the performance. / Syfte och frågeställningar Huvudsyftet med denna studie var att undersöka de longitudinella effekter på prestation i cykling med hjälp av ett polariserat och periodiserat träningsupplägg som var väl övervakat och kontrollerat. Det andra syftet var att undersöka effekten av att använda hyperoxi. De frågeställningar som hjälpte att besvara syftet var: (1) Hur förändras prestationen efter en sex veckors träningsintervention? (2) Hur anpassar sig försökspersonerna till träningsschemat över tid?  (3) Hur förändras prestationen inom grupperna?   Metod 19 manliga och kvinnliga cyklister deltog i studien (13 manliga och 6 kvinnliga), 12 fullföljde hela studien (8 manliga och 4 kvinnliga). Karaktäristiken för de 12 försökspersonerna var: ålder (år) 33.6 ± 6.8, längd (cm) 177 ± 9.1, vikt (kg) 73.4 ± 8.8. Försökspersonerna delades in i hyperoxi (HOT) (n = 6) och normoxi (NOT) (n = 6), studien var dubbelblind. Under sex veckor följde försökspersonerna en kontrollerad polariserad periodisering som inkluderade 15 högintensiva intervallträningspass (HIIT) (3 x 8 min, 3 x 8 + 4 min, 4 x 8 min &amp; 4 x 4 min) på högsta genomförbara intensitet (isoeffort) på cykelergometer. Doseringen av syre administrerades intermittent genom Oxelerate-enheten. Ett 20 min all-out test utfördes som för- och eftertest.   Resultat Hela gruppen (n = 12) ökade signifikant på prestationstestet (W) med 6.4 % (P = 0.002). Den relativa effekten (W/kg) ökade signifikant med 8.2% (P = 0.0011). HOT (n = 6) ökade signifikant på prestationstestet med 8.3% (P = 0.028) och den relativa effekten ökade med 9.4% (P = 0.011). Hela gruppen (n = 12) ökade signifikant i VO2medel under prestationstestet med 4.1 % (P = 0.03) och i det relativa värdet med 5.4 % (P = 0.01). Hela gruppen hade också en signifikant ökning av VO2peak med 3.7 % (P = 0.04). En mycket stark korrelation hittades mellan träningspassdata och prestationstestet.   Slutsats Träningsupplägget är gynnsamt för ökning av prestation och VO2peak i cykling. Användning av hyperoxi under träningsupplägget ökar prestationen.