Academic literature on the topic 'Maximales Laktat-steady-state'

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.

This study reviewed first the development of race result in canoe sprint during the past decades. The race results of MK1-1000 and WK1-500 have increased 32.5 % and 42.1 %, respectively, a corresponding 5.0 % and 6.5 % increase in each decade. The development of race results in canoe sprint during the past decades resulted from the contributions of various aspects. The recruitment of taller and stronger athletes improved the physiological capacity of paddlers. Direct investigation on energy contribution in canoe sprint enhanced the emphasis on aerobic capacity and aerobic endurance training. Advancement of equipment design improved the efficiency of paddling. Physiological and biomechanical diagnostics in canoe sprint led to a more scientific way of training. Additionally, other aspects might also have contributed to the development of race results during the past decades. For example, the establishment of national team after World War II provided the possibility of systematic training, and the use of drugs in the last century accelerated the development of race results in that period. Recent investigations on energetics in high-intensity exercises demonstrated an underestimate of WAER % in the table provided by some textbooks since the 1960s. An exponential correlation between WAER % and the duration of high-intensity exercises was concluded from summarizing most of the relevant reports, including reports with different methods of energy calculation. However, when reports with the MAOD and Pcr-La-O2 methods were summarized separately, a greater overestimate of WAER % from MAOD was found compared to those from Pcr-La-O2, which was in line with the critical reports on MAOD. Because of the lack of investigation of the validity of the comparisons between MAOD and Pcr-La-O2, it is still not clear which method can generate more accurate results and which method is more reliable. With regard to kayaking, a range of variation in WAER % was observed. Many factors might contribute to the variation of WAER % in kayaking. Therefore, the methods utilized to calculate the energy contributions, different paddling conditions, and the level of performance were investigated in kayaking. The findings indicated that the method utilized to calculate the energy contributions in kayaking, rather than paddling condition and performance level of paddlers, might be the possible factor associated with WAER %. Some other possible factors associated with WAER % still need to be further investigated in the future. After verifying the dependence of WAER % on the method of energy calculation, but not on paddling condition and performance level of paddlers, energy contributions of kayaking were investigated for the three racing distances on a kayak ergometer with junior paddlers. Energetic profiles in kayaking varied with paddling distances. At 500 m and 1000 m the aerobic system was dominant (with WAER % of 57.8 % and 76.2 %), whereas at 200 m the anaerobic system was dominant (with WAER % of 31.1-32.4 %). Muscular volume seemed to have an influence on absolute energy productions. The anaerobic alactic system determined the performance during the first 5 to 10 s. The anaerobic lactic system probably played a dominant role during the period from the 5th-10th s to 30th-40th s. The aerobic system could dominate the energy contribution after 30–40 s. This energetic profile in kayaking could provide physiological support for developing the training philosophy in these three distances. Additionally, the method introduced by Beneke et al. seemed to be a valid method to calculate the energy contributions in maximal kayaking. Energy contributions in canoeing were similar to those in kayaking. The relative energy contributions on open water canoeing were 75.3 ± 2.8 % of aerobic, 11.5 ± 1.9 % of anaerobic lactic, and 13.2 ± 1.9 % of anaerobic alactic at maximal speed of simulated 1000 m. Further, the C of canoeing seemed also to be similar to the reported findings in kayaking, with a function of y = 0.0242 * x2.1225. Training programs could be designed similarly for kayaking and canoeing with regard to energetic profile. In order to extend the findings on energetics in canoe sprint to other exercises, energy contributions in kayaking, canoeing, running, cycling, as well as arm cranking were compared with the same duration. Results indicated that WAER % during maximal exercises with the same duration seemed to be independent of movement patterns, given similar VO2 kinetics during the maximal exertion. The exponential relationship between WAER % and duration in maximal exercises could be supported by excluding the influence from movement patterns. Additionally, MLSS in kayaking was investigated. The blood lactate value of MLSS was found to be 5.4 mM in kayaking, which could expand the knowledge of MLSS in different locomotion. The MLSS in kayaking might be attributed to the involved muscle mass in this locomotion, which could result in a certain level of lactate removal, and allow a certain level of equilibrium between lactate production and removal. LT5, instead of LT4, was recommended for diagnostics in kayaking, given an incremental test as used in this study.

Das maximale Laktat-Steady-State (MLSS) ist die Belastungsintensität bei der sich gerade noch ein Fließgleichgewicht von Laktatbildung und -elimination einstellt. Dazu gibt es in der Literatur zahlreiche Messverfahren, denen eine Bestimmung der Laktatkonzentration im Blut zugrunde liegt. Den meisten dieser Verfahren fehlt allerdings eine biologisch-theoretische Grundlage. Aus diesem Grund haben Mader und Heck bereits Mitte der 80er Jahre ein mathematisches Modell erarbeitet, welches das Zustandekommen des MLSS unter steady-state Bedingungen auf theoretischer Basis erklärt. Dieses steady-state Modell beruht primär auf der Kenntnis der maximalen Sauerstoffaufnahme sowie der maximalen Laktatbildungsrate als Parameter der maximalen Leistungsfähigkeit der Atmung und der Glykolyse. Mit diesem theoretischen Modell zur Beschreibung der Funktion des Energiestoffwechsels unter Belastung können Trainingseffekte erklärt und Unterschiede zwischen Sportlern verstanden werden. Trotzdem wurden die durch Mader und Mitarbeiter angestellten theoretischen Überlegungen zum Verhalten des Energiestoffwechsels bisher nur zum Teil in der Praxis validiert und fanden bislang keinen breiten Eingang in sportmedizinischen Untersuchungen. Die vorliegende kumulativ angefertigte Arbeit umfasst daher vier Veröffentlichungen: Den Vergleich verschiedener Laktat-Schwellenkonzepte mit dem experimentell bestimmten MLSS, den Vergleich des theoretischen Modells des Energiestoffwechsels mit dem experimentell bestimmten MLSS, die Bestimmung der Reliabilität des theoretischen Modells des Energiestoffwechsels und die Untersuchung des Effektes einer Sprint- und Ausdauerbelastung auf die maximale Laktatbildungsrate, die maximale Sauerstoffaufnahme sowie das berechnete MLSS.

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.

This study reviewed first the development of race result in canoe sprint during the past decades. The race results of MK1-1000 and WK1-500 have increased 32.5 % and 42.1 %, respectively, a corresponding 5.0 % and 6.5 % increase in each decade. The development of race results in canoe sprint during the past decades resulted from the contributions of various aspects. The recruitment of taller and stronger athletes improved the physiological capacity of paddlers. Direct investigation on energy contribution in canoe sprint enhanced the emphasis on aerobic capacity and aerobic endurance training. Advancement of equipment design improved the efficiency of paddling. Physiological and biomechanical diagnostics in canoe sprint led to a more scientific way of training. Additionally, other aspects might also have contributed to the development of race results during the past decades. For example, the establishment of national team after World War II provided the possibility of systematic training, and the use of drugs in the last century accelerated the development of race results in that period. Recent investigations on energetics in high-intensity exercises demonstrated an underestimate of WAER % in the table provided by some textbooks since the 1960s. An exponential correlation between WAER % and the duration of high-intensity exercises was concluded from summarizing most of the relevant reports, including reports with different methods of energy calculation. However, when reports with the MAOD and Pcr-La-O2 methods were summarized separately, a greater overestimate of WAER % from MAOD was found compared to those from Pcr-La-O2, which was in line with the critical reports on MAOD. Because of the lack of investigation of the validity of the comparisons between MAOD and Pcr-La-O2, it is still not clear which method can generate more accurate results and which method is more reliable. With regard to kayaking, a range of variation in WAER % was observed. Many factors might contribute to the variation of WAER % in kayaking. Therefore, the methods utilized to calculate the energy contributions, different paddling conditions, and the level of performance were investigated in kayaking. The findings indicated that the method utilized to calculate the energy contributions in kayaking, rather than paddling condition and performance level of paddlers, might be the possible factor associated with WAER %. Some other possible factors associated with WAER % still need to be further investigated in the future. After verifying the dependence of WAER % on the method of energy calculation, but not on paddling condition and performance level of paddlers, energy contributions of kayaking were investigated for the three racing distances on a kayak ergometer with junior paddlers. Energetic profiles in kayaking varied with paddling distances. At 500 m and 1000 m the aerobic system was dominant (with WAER % of 57.8 % and 76.2 %), whereas at 200 m the anaerobic system was dominant (with WAER % of 31.1-32.4 %). Muscular volume seemed to have an influence on absolute energy productions. The anaerobic alactic system determined the performance during the first 5 to 10 s. The anaerobic lactic system probably played a dominant role during the period from the 5th-10th s to 30th-40th s. The aerobic system could dominate the energy contribution after 30–40 s. This energetic profile in kayaking could provide physiological support for developing the training philosophy in these three distances. Additionally, the method introduced by Beneke et al. seemed to be a valid method to calculate the energy contributions in maximal kayaking. Energy contributions in canoeing were similar to those in kayaking. The relative energy contributions on open water canoeing were 75.3 ± 2.8 % of aerobic, 11.5 ± 1.9 % of anaerobic lactic, and 13.2 ± 1.9 % of anaerobic alactic at maximal speed of simulated 1000 m. Further, the C of canoeing seemed also to be similar to the reported findings in kayaking, with a function of y = 0.0242 * x2.1225. Training programs could be designed similarly for kayaking and canoeing with regard to energetic profile. In order to extend the findings on energetics in canoe sprint to other exercises, energy contributions in kayaking, canoeing, running, cycling, as well as arm cranking were compared with the same duration. Results indicated that WAER % during maximal exercises with the same duration seemed to be independent of movement patterns, given similar VO2 kinetics during the maximal exertion. The exponential relationship between WAER % and duration in maximal exercises could be supported by excluding the influence from movement patterns. Additionally, MLSS in kayaking was investigated. The blood lactate value of MLSS was found to be 5.4 mM in kayaking, which could expand the knowledge of MLSS in different locomotion. The MLSS in kayaking might be attributed to the involved muscle mass in this locomotion, which could result in a certain level of lactate removal, and allow a certain level of equilibrium between lactate production and removal. LT5, instead of LT4, was recommended for diagnostics in kayaking, given an incremental test as used in this study.