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  • 51.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Sport and Health Science.
    Hur många stulna medaljer?2012In: Idrott och Kunskap, ISSN 1652-6961, no 4, p. 58-59Article in journal (Other (popular science, discussion, etc.))
  • 52.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Sport and Health Science.
    Hur tränar man explosiv styrka bäst?2009In: Idrott och Kunskap, ISSN 1652-6961, p. 52-53Article in journal (Other academic)
  • 53.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Idrottsmedicinen sviker barnen2012In: Svenska Dagbladet, ISSN 1101-2412, no 25 nov, p. 5-5Article in journal (Other (popular science, discussion, etc.))
  • 54.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Inget ont som inte medför något gott2018In: här&nu, ISSN 1653-2287, no 5, p. 9-Article in journal (Other (popular science, discussion, etc.))
  • 55.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Medical Science.
    Inverkan av akut arbete, träning och oxidativ stress på mitokondriell funktion och termogenes i human skelettmuskulatur.1999In: Svensk Idrottsmedicin, ISSN 1103-7652, no 2, p. 5-10Article in journal (Other academic)
  • 56.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Jag vill leva jag vill dö i Norden...2016In: här&nu, ISSN 1653-2287, no 6, p. 15-15Article in journal (Other (popular science, discussion, etc.))
  • 57.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Klassa efter syreupptagning bättre sätt att stoppa doping2018In: Dagens Nyheter, ISSN 1101-2447, no 2018-02-10, p. 5-5Article in journal (Other (popular science, discussion, etc.))
  • 58.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Lagstifta om att barn måste röra på sig2019In: Svenska dagbladet, ISSN 1101-2412, , p. 1article id 2019-11-22Article in journal (Other (popular science, discussion, etc.))
  • 59.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Sport and Health Science.
    Mest är inte alltid bäst2011In: Idrott och Kunskap, ISSN 1652-6961, no 3, p. 56-57Article in journal (Other (popular science, discussion, etc.))
  • 60.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Medical Science.
    Mitochondrial function in human skeletal muscle: with special reference to exercise and training.2000Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The overall objective of this thesis was to study the adaptation of oxidative function in human skeletal muscle to acute exercise of different modes, intensities and durations, and to endurance training. The effects of endurance training on mitochondrial function were evaluated in cross-sectional and longitudinal studies by measurements of mitochondrial oxygen consumption in isolated mitochondria and permeabilised muscle fibres and measurements of mitochondrial ATP production rate in isolated mitochondria. A positive correlation was observed between maximal mitochondrial oxidative power measured in isolated mitochondria and permeabilised muscle fibres and other parameters related to local and whole body aerobic training status such as pulmonary maximal oxygen uptake, lactate threshold, and muscle activity of citrate synthase (CS). Previous studies have demonstrated that ADP and creatine are important regulators of oxidative phosphorylation. We found that the sensitivity of oxidative phosphorylation to ADP at the level of individual mitochondrion exhibits negative correlation with training status, whereas the creatine control of mitochondrial respiration is more pronounced in aerobically well-trained individuals. It is suggested that these adaptations may improve the potential for regulation of oxidative metabolism in trained muscle. The sensitivity of proton leakdependent oxygen consumption in isolated mitochondria to free fatty acids was up-regulated by a short-term endurance-training program. This may contribute to a higher basal metabolic rate in endurance-trained individuals. It is also suggested that this adaptation may prevent excessive free radical generation and enhance the potential for regulation of aerobic energy production in trained muscle. Exposure of isolated mitochondria to reactive oxygen species (ROS) reduced maximal ADP-stimulated respiration and P/O ratio and increased noncoupled respiration rate. The sensitivity of non-coupled respiration in isolated mitochondria to ROS was increased by 6 wk of endurance training, whereas the sensitivity of maximal ADP-stimulated respiration and P/O ratio to ROS was unaffected. These results indicate that inner mitochondrial membrane becomes more sensitive to oxidative stress after short-term endurance training. Activities of muscle antioxidative enzymes (SOD, GPX) and glutathione status were unaffected by training. This will result in a lowered antioxidative protection per mitochondrion, which may increase the susceptibility of inner membrane to oxidative stress. Maximal mitochondrial oxidative power in human vastus lateralis muscle was found to be intact or improved after high-intensity intermittent and moderate-intensity prolonged concentric cycling exercise as well as after eccentric cycling. Prolonged exercise increased the non-coupled mitochondrial respiration rate, which may contribute to the excess post-exercise oxygen consumption. After prolonged exercise an acute increase in muscle CS activity was observed. High-intensity intermittent exercise affected the ADP control of oxidative phosphorylation, as evidenced by transient decrease in ADP sensitivity of mitochondrial respiration in permeabilised muscle fibres. ADP sensitivity was unchanged after prolonged concentric and high-intensity eccentric exercise. Taken together these results indicate that mitochondrial function in human muscle is affected differently by exercise of different types. The effect of lactic acidosis on oxidative phosphorylation was evaluated in isolated mitochondria from rat skeletal muscle. It was demonstrated that acidosis induced on non-phosphorylating mitochondria reduces rate of subsequent maximal ADP-stimulated respiration. In contrast, when actively phosphorylating mitochondria were exposed to acidosis maximal ADP-stimulated respiration remained unchanged. On the basis of these results we suggested that the influence of lactic acidosis on muscle aerobic energy production may depend on the physiological conditions at the onset of acidity. Overall, the present investigations indicate that mitochondrial oxidative function is highly responsive to exercise. Endurance training induces adaptation of both quantitative and qualitative aspects of mitochondrial function, which improves the potential for metabolic control. The results suggest that acute physical exercise in humans is, in contrast to previous animal studies, well tolerated by skeletal muscle mitochondria.

  • 61.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Medical Science.
    Mitokondrier – muskelcellernas kraftverk: anpassnings- och överlevnadskonstnärer som är avgörande för prestation och hälsa.2001In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, no 1, p. 44-47Article in journal (Other academic)
  • 62.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Musiken kan ge oss bättre resultat2017In: Här&Nu, ISSN 1653-2287, no 6, p. 17-Article in journal (Other (popular science, discussion, etc.))
  • 63.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Medical Science.
    Muskulaturens förmåga att utnyttja syre är avgörande för prestation och hälsa1998In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, no 3, p. 34-37Article in journal (Other academic)
  • 64.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Sport and Health Science.
    Om korta, tydliga råd och sammanfattningsrutor…2012In: Idrott och Kunskap, ISSN 1652-6961, no 3, p. 54-55Article in journal (Other (popular science, discussion, etc.))
  • 65.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Rörelse bästa bot vid artros2017In: här&nu, ISSN 1653-2287, no 3, p. 11-Article in journal (Other (popular science, discussion, etc.))
  • 66.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Små förändringar ger stor effekt2018In: här&nu, ISSN 1653-2287, no 4, p. 13-Article in journal (Other (popular science, discussion, etc.))
  • 67.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Sport and Health Science.
    Statisk uthållighet i bågskytte2012In: Bågskytten, ISSN 0345-1216, Vol. 65, no 11, p. 18-20Article in journal (Other (popular science, discussion, etc.))
  • 68.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Styrketräna för hjärtat2017In: här&nu, ISSN 1653-2287, no 2, p. 23-Article in journal (Other (popular science, discussion, etc.))
  • 69.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Styrketräning bra för balansen2016In: här&nu, ISSN 1653-2287, no 5, p. 11-11Article in journal (Other (popular science, discussion, etc.))
  • 70.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Medical Science.
    Styrketräning för barn - bu eller bä?2007In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, no 1, p. 38-43Article in journal (Other academic)
  • 71.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Sport and Health Science.
    Styrketräning för barn: del 1: Var står vi nu?2009In: Svensk Idrottsmedicin, ISSN 1103-7652, no 4, p. 6-12Article in journal (Other academic)
  • 72.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Medical Science.
    Styrketräning för barn: Sverige i det internationella perspektivet2013In: Vaskulär Medicin, ISSN 2000-3188, Vol. 29, no 1, p. 15-18Article in journal (Other academic)
  • 73.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Medical Science.
    Styrketräning för bågskyttar2013In: Bågskytten, ISSN 0345-1216, Vol. 66, no 1-2, p. 12-15Article in journal (Other (popular science, discussion, etc.))
  • 74.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Medical Science.
    Styrketräning för friska och sjuka barn: Det internationella perspektivet2013In: Barnbladet, ISSN 0349-1994, Vol. XXXVIII, no 4, p. 14-16Article in journal (Other academic)
  • 75.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Sport and Health Science.
    Styrketräning för unga2015In: Skolhälsan, ISSN 0284-284X, no 1, p. 10-11Article in journal (Other academic)
  • 76.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Styrketräning för unga bågskyttar2016In: Bågskytten, ISSN 0345-1216, Vol. 69, no 7, p. 12-15Article in journal (Other (popular science, discussion, etc.))
  • 77.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Sport and Health Science.
    Styrketräning är positivt för barns utveckling2012In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, no 2, p. 53-54Article in journal (Other academic)
  • 78.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Sport and Health Science.
    Styrkt av träning2015In: Äldre i Centrum, ISSN 1653-3585, Vol. 29, no 4, p. 21-23Article in journal (Other academic)
  • 79.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Sport and Health Science.
    Tidig allsidig specialisering2010In: Idrott och kunskap, ISSN 1652-6961, p. 60-61Article in journal (Refereed)
  • 80.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Träna bort depressioner2017In: här&nu, ISSN 1653-2287, no 1, p. 11-Article in journal (Other (popular science, discussion, etc.))
  • 81.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Träning bra för nära relationer2016In: här&nu, ISSN 1653-2287, no 4, p. 13-13Article in journal (Other (popular science, discussion, etc.))
  • 82.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Träning för hälsa och relationer2017In: Äldreomsorg, ISSN 1403-7025, no 3, p. 33-34Article in journal (Other (popular science, discussion, etc.))
  • 83.
    Tonkonogi, Michail
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Träningslärans grunder - fysiska grundegenskaper och träningsprinciper2018In: Idrottens träning, Stockholm: SISU Idrottsböcker , 2018, p. 22-57Chapter in book (Other academic)
  • 84.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Sport and Health Science.
    Träningsplanering2010In: Idrott och Kunskap, ISSN 1652-6961, p. 60-61Article in journal (Refereed)
  • 85.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Sport and Health Science.
    Uthållighetsträning och kolhydrater: det stora missförståndet2012In: Idrott & Kunskap, ISSN 1652-6961, no 5, p. 58-59Article in journal (Other (popular science, discussion, etc.))
  • 86.
    Tonkonogi, Michail
    Dalarna University, School of Health and Social Studies, Sport and Health Science.
    Är din uppvärmning optimal? 2011In: Idrott och Kunskap, ISSN 1652-6961, no 5, p. 58-59Article in journal (Other (popular science, discussion, etc.))
  • 87.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Health and Social Studies, Medical Science.
    Bellardini, Helena
    Dalarna University, School of Health and Social Studies, Sport and Health Science.
    Fysisk trening for barn och ungdom: for helse, allsidig utvikling og prestasjon2013 (ed. 1)Book (Other (popular science, discussion, etc.))
  • 88.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Bellardini, Helena
    Dalarna University, School of Education, Health and Social Studies, Sport and Health Science.
    Träna bort den stressrelaterade ohälsan2016 (ed. 1)Book (Other academic)
  • 89.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Education, Health and Social Studies, Sport and Health Science.
    Bellardini, Helena
    Dalarna University, School of Education, Health and Social Studies, Sport and Health Science.
    Träna bort övervikten med FATREX2014 (ed. 1)Book (Other academic)
  • 90.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Bellardini, Helena
    Dalarna University, School of Education, Health and Social Studies, Sport and Health Science.
    Tunga vikter för en lättare ålderdom2013In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 22, no 3, p. 8-12Article in journal (Other academic)
  • 91.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Education, Health and Social Studies, Sport and Health Science.
    Bellardini, Helena
    Dalarna University, School of Education, Health and Social Studies, Sport and Health Science.
    Åldersanpassad fysisk träning för barn och ungdomar2012 (ed. 1)Book (Other academic)
  • 92.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Health and Social Studies, Medical Science.
    Fernström, Maria
    Walsh, Brandon
    Ji, Li Li
    Rooyackers, Olav
    Hammaqvist, Folke
    Wernerman, Jan
    Sahlin, Kent
    Reduced oxidative power but unchanged antioxidative capacity in skeletal muscle from aged humans.2003In: Pflügers Archiv: European Journal of Physiology, ISSN 0031-6768, E-ISSN 1432-2013, Vol. 446, no 2, p. 261-269Article in journal (Refereed)
    Abstract [en]

    The hypothesis that the aging process is associated with mitochondrial dysfunction and oxidative stress has been investigated in human skeletal muscle. Muscle biopsy samples were taken from seven old male subjects [OS; 75 (range 61-86) years] and eight young male subjects [YS; 25 (22-31) years]. Oxidative function was measured both in permeabilised muscle fibres and isolated mitochondria. Despite matching the degree of physical activity, OS had a lower training status than YS as judged from pulmonary maximal O2 consumption (V£O2max, m36%) and handgrip strength (m20%). Both maximal respiration and creatine-stimulated respiration were reduced in muscle fibres from OS (m32 and m34%, respectively). In contrast, respiration in isolated mitochondria was similar in OS and YS. The discrepancy might be explained by a biased harvest of "healthy" mitochondria and/or disruption of structural components during the process of isolation. Cytochrome C oxidase was reduced (m40%, P<0.01), whereas UCP3 protein tended to be elevated in OS (P=0.09). Generation of reactive oxygen species by isolated mitochondria and measures of antioxidative defence (muscle content of glutathione, glutathione redox status, antioxidative enzymes activity) were not significantly different between OS and YS. It is concluded that aging is associated with mitochondrial dysfunction, which appears to be unrelated to reduced physical activity. The hypothesis of increased oxidative stress in aged muscle could not be confirmed in this study.

  • 93.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Health and Social Studies, Medical Science.
    Harris, Bearn
    Sahlin, Kent
    Increased activity of citrate synthase in human skeletal muscle after a single bout of prolonged exercise.1997In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 161, p. 435-436Article in journal (Refereed)
  • 94.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Health and Social Studies, Medical Science.
    Harris, Bearn
    Sahlin, Kent
    Mitochondrial oxidative function in human saponin-skinned muscle fibres: effects of prolonged exercise.1998In: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 510, p. 279-286Article in journal (Refereed)
    Abstract [en]

    1. The influence of prolonged exhaustive exercise on mitochondrial oxidative function was investigated in ten men. 2. Muscle biopsies were taken before and after exercise and mitochondrial respiration investigated in fibre bundles made permeable by pretreatment with saponin. 3. After exercise, respiration in the absence of ADP increased by 18 % (P< 0.01), but respiration at suboptimal ADP concentration (0.1 mM) and maximal ADP-stimulated respiration (1 mM ADP) remained unchanged. 4. In the presence of creatine (20 mM), mitochondrial affinity for ADP increased markedly and respiration at suboptimal ADP concentration (0.1 mM) was similar (pre-exercise) or higher (post-exercise; P< 0.05) than with 1 mM ADP alone. The increase in respiratory rate with creatine was correlated to the relative type I fibre area (r = 0.84). Creatine-stimulated respiration increased after prolonged exercise (P< 0.01). 5. The respiratory control index (6.8 ± 0.4, mean ± s.e.m.) and the ratio between respiration at 0.1 and 1 mM ADP (ADP sensitivity index, 0.63 ± 0.03) were not changed after exercise. The sensitivity index was negatively correlated to the relative type I fibre area (r = -0.86). 6. The influence of exercise on muscle oxidative function has for the first time been investigated with the skinned-fibre technique. It is concluded that maximal mitochondrial oxidative power is intact or improved after prolonged exercise, while uncoupled respiration is increased. The latter finding may contribute to the elevated post-exercise oxygen consumption. The finding that the sensitivity of mitochondrial respiration for ADP and creatine are related to fibre-type composition indicates intrinsic differences in the control of mitochondrial respiration between fibres.

  • 95.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Hawke, Emma
    Dalarna University, School of Education, Health and Social Studies, Sport and Health Science.
    The way that physical education aims to provide the recommended dose of physical activity in school children is multifaceted2017In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 106, no 1, p. 12-13Article in journal (Other academic)
  • 96.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Health and Social Studies, Medical Science.
    Henriksson, Jan
    Cotgreave, Ian
    Human skeletal muscle interstitial glutathione levels are elevated in comparison to adipose tissue and blood plasma.2003In: Archives of Biochemistry and Biophysics, ISSN 0003-9861, E-ISSN 1096-0384, Vol. 413, no 1, p. 147-149Article in journal (Refereed)
  • 97.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Health and Social Studies, Medical Science.
    Krook, Anna
    Walsh, Brandon
    Sahlin, Kent
    Endurance training increases stimulation of uncoupling of skeletal muscle mitochondria in humans by non-esterified fatty acids: an uncoupling-protein-mediated effect?2000In: Biochemical Journal, ISSN 0264-6021, E-ISSN 1470-8728, Vol. 351, no 3, p. 805-810Article in journal (Refereed)
    Abstract [en]

    Uncoupled respiration (UCR) is an essential property of muscle mitochondria and has several functions in the cell. We hypothesized that endurance training may alter the magnitude and properties of UCR in human muscle. Isolated mitochondria from muscle biopsies taken before and after 6 weeks of endurance exercise training (n = 8) were analysed for UCR. To investigate the role of uncoupling protein 2 (UCP2) and UCP3 in UCR, the sensitivity of UCR to UCP-regulating ligands (non-esterified fatty acids and purine nucleotides) and UCP2 and UCP3 mRNA expression in muscle were examined. Oleate increased the mitochondrial oxygen consumption rate, an effect that was not attenuated by GDP and/or cyclosporin A. The effect of oleate was significantly greater after compared with before training. Training had no effect on UCP2 or UCP3 mRNA levels, but after training the relative increase in respiration rate induced by oleate was positively correlated with the UCP2 mRNA level. In conclusion, we show that the sensitivity of UCR to non-esterified fatty acids is up-regulated by endurance training. This suggests that endurance training causes intrinsic changes in mitochondrial function, which may enhance the potential for regulation of aerobic energy production, prevent excess free radical generation and contribute to a higher basal metabolic rate.

  • 98.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Health and Social Studies, Medical Science.
    Sahlin, Kent
    Actively phosphorylating mitochondria are more resistant to lactic acidosis than inactive mitochondria.1999In: American Journal of Physiology. Cell Physiology, ISSN  0363-6143, Vol. 277, no 2, p. C288-C293Article in journal (Refereed)
    Abstract [en]

    Oxidative phosphorylation of isolated rat skeletal muscle mitochondria after exposure to lactic acidosis in either phosphorylating or nonphosphorylating states has been evaluated. Mitochondrial respiration and transmembrane potential (Delta Psi m) were measured with pyruvate and malate as the substrates. The addition of lactic acid decreased the pH of the reaction medium from 7.5 to 6.4. When lactic acid was added to nonphosphorylating mitochondria, the subsequent maximal ADP-stimulated respiration decreased by 27% compared with that under control conditions (P < 0.05), and the apparent Michaelis-Menten constant (Km) for ADP decreased to 10 µM vs. 20 µM (P < 0.05) in controls. In contrast, maximal respiration and ADP sensitivity were not affected when mitochondria were exposed to acidosis during active phosphorylation in state 3. Acidosis significantly increased mitochondrial oxygen consumption in state 4 (post-state 3), irrespective of when acidosis was induced. This effect of acidosis was attenuated in the presence of oligomycin. The addition of lactic acid during state 4 respiration decreased Delta Psi m by 19%. The ratio between added ADP and consumed oxygen (P/O) was close to the theoretical value of 3 in all conditions. The addition of potassium lactate during state 3 (i.e., medium pH unchanged) had no effect on the parameters measured. It is concluded that lactic acidosis has different effects when induced on nonphosphorylating vs. actively phosphorylating mitochondria. On the basis of these results, we suggest that the influence of lactic acidosis on muscle aerobic energy production depends on the physiological conditions at the onset of acidity.

  • 99.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Health and Social Studies, Medical Science.
    Sahlin, Kent
    Physical exercise and mitochondrial function in human skeletal muscle.2002In: Exercise and Sport Sciences Reviews, ISSN  0091-6331, Vol. 30, no 3, p. 129-137Article in journal (Refereed)
    Abstract [en]

    Muscle adaptation to endurance training involves qualitative changes in intrinsic properties of mitochondria. After training, the ADP sensitivity of mitochondrion is decreased whereas the effect of creatine on respiration is increased. This results in an improved control of aerobic energy production. Acute exercise does not adversely affect mitochondrial function.

  • 100.
    Tonkonogi, Michail
    et al.
    Dalarna University, School of Health and Social Studies, Medical Science.
    Sahlin, Kent
    Rate of oxidative phosphorylation in isolated mitochondria from human skeletal muscle: effect of training status.1997In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 161, p. 345-353Article in journal (Refereed)
    Abstract [en]

    Muscle oxidative function has been investigated in subjects with various training status (VO2 max, 41–72 mL O2 kg-1 body wt min-1, n=10). Mitochondria were isolated from biopsies taken from m. vastus lateralis. Maximal mitochondrial oxygen consumption (QO2) and ATP production (MAPR) were measured with polarographic and bioluminometric techniques, respectively. The yield of mitochondria, calculated from the fractional activity of citrate synthase (CS), averaged 26%. With pyruvate + malate, the respiratory control ratio was 5.7 ± 0.4 (X ± SE) and the P/O ratio was 2.83 ± 0.02, which demonstrates that the isolated mitochondria were functionally intact. QO2 was significantly correlated to aerobic training status expressed as muscle CS activity (r=0.86), VO2 max (r=0.84) and lactate threshold (r=0.83) but not to the fibre type composition. A highly significant correlation (r=0.93) was observed between ATP production calculated from QO2 and MAPR, but ATP production derived from QO2 was higher than MAPR both for pyruvate + malate (255%) and for a-ketoglutarate (23%). QO2 extrapolated to a temperature of 38 °C averaged 68 mL O2 min-1 kg-1 wet wt, which is similar to previous findings in vitro and in vivo during the post-exercise period. However, calculated muscle O2 utilization during exercise was three- to fivefold higher than QO2 measured on isolated mitochondria. It is suggested that additional factors exist for activation of mitochondrial respiration during exercise. It is concluded that muscle oxidative function can be quantitatively assessed from the respiration of mitochondria isolated from needle biopsy specimens and that QO2 is closely correlated to whole-body VO2 max.

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