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1
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High content of MyHC II in vastus lateralis is accompanied by higher VO2/power output ratio during moderate intensity cycling performed both at low and at high pedalling rates

100%
Majerczak J., Szkutnik Z., Karasinski J., Duda K., Kolodziejski L., Zoladz J. A.
Journal of Physiology and Pharmacology
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2006
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tom 57
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nr 2
The aim of this study was to examine the relationship between the content of various types of myosin heavy chain isoforms (MyHC) in the vastus lateralis muscle and pulmonary oxygen uptake during moderate power output incremental exercise, performed at low and at high pedalling rates. Twenty one male subjects (mean ± SD) aged 24.1 ± 2.8 years; body mass 72.9 ± 7.2 kg; height 179.1 ± 4.8 cm; BMI 22.69 ± 1.89 kg . m-2; VO2max 50.6 ± 5.3 ml . kg . min-1, participated in this study. On separate days, they performed two incremental exercise tests at 60 rev . min-1 and at 120 rev . min-1, until exhaustion. Gas exchange variables were measured continuously breath by breath. Blood samples were taken for measurements of plasma lactate concentration prior to the exercise test and at the end of each step of the incremental exercise. Muscle biopsies were taken from the vastus lateralis muscle, using Bergström needle, and they were analysed for the content of MyHC I and MyHC II using SDS - PAGE and two groups (n=7, each) were selected: group H with the highest content of MyHC II (60.7 % ± 10.5 %) and group L with the lowest content of MyHC II (27.6 % ± 6.1 %). We have found that during incremental exercise at the power output between 30 - 120 W, performed at 60 rev . min-1, oxygen uptake in the group H was significantly greater than in the group L (ANCOVA, p=0.003, upward shift of the intercept in VO2 / power output relationship). During cycling at the same power output but at 120 rev . min-1, the oxygen uptake was also higher in the group H, when compared to the group L (i.e. upward shift of the intercept in VO2 / power output relationship, ANCOVA, p=0.002). Moreover, the increase in pedalling rate from 60 to 120 rev . min-1 was accompanied by a significantly higher increase of oxygen cost of cycling and by a significantly higher plasma lactate concentration in subjects from group H. We concluded that the muscle mechanical efficiency, expressed by the VO2 / PO ratio, during cycling in the range of power outputs 30 - 120 W, performed at 60 as well as 120 rev . min-1, is significantly lower in the individuals with the highest content of MyHC II, when compared to the individuals with the lowest content of MyHC II in the vastus lateralis.
2
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Effect of moderate incremental exercise, performed in fed and fasted state on cardio-respiratory variables and leptin and ghrelin concentrations in young healthy men

84%
Zoladz J. A., Konturek S. J., Duda K., Majerczak J., Sliwowski Z., Grandys M., Bielanski W.
Journal of Physiology and Pharmacology
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2005
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tom 56
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nr 1
Background: Although hormonal responses to exercise performed in fed state are well documented, far less in known about the effect of a single exercise bout, performed after overnight fasting, on cardio-respiratory responses and hormones secretion. It has been reported that recently discovered hormones as leptin and ghrelin may affect cardiovascular responses at rest. However, their effect on the cardiovascular responses to exercise is unknown. Aims: This study was designed to determine the effect of overnight fasting on cardio- respiratory responses during moderate incremental exercise. We have hypothesised that fasting / exercise induced changes in plasma leptin / ghrelin concentrations may influence cardiovascular response. Material and Methods: Eight healthy non-smoking men (means ± SE.: age 23.0 ± 0.5 years; body mass 71.9 ± 1.5 kg; height 179.1 ± 0.8 cm; BMI 22.42 ± 0.49 kg . m-2 with VO2max of 3.71 ± 0.10 l . min-1) volunteered for this study. The subjects performed twice an incremental exercise test, with the increase of power output by 30 W every 3 minutes. Tests were performed in a random order: once in the feed state - cycling until exhaustion and second, about one week later, after overnight fasting - cycling until reaching 150 W. Results: In the present study we have compared the results obtained during incremental exercise performed only up to 150 W (59 ± 2 % of VO2max) both in fed and fasted state. Heart rate measured during exercise at each power output, performed in fasted state was by about 10 bt . min-1 (p = 0.02) lower then in fed subjects. Respiratory quotient and plasma lactate concentration in fasted state were also significantly (p<0.001) lower than in the fed state. Pre-exercise plasma leptin and ghrelin concentrations were not significantly different in fed and fasted state. Exercise induced increase in hGH was not accompanied by a significant changes in the studied gut hormones such as ghrelin, leptin, and insulin, except for plasma gastrin concentration, which was significantly (p = 0.008) lower in fasting subjects at the power output of 150 W. Plasma [IL-6] at rest before exercise performed in fasted state was significantly (p = 0.03) elevated in relation to the fed state. This was accompanied by significantly higher (p = 0.047) plasma noradrenaline concentration. Plasma IL-6 concentration at rest in fed subjects was negatively correlated with plasma ghrelin concentration (r = - 0.73, p < 0.05) and positively correlated with plasma insulin concentration (r = 0.78, p < 0.05). Significant negative correlation (r = - 0.90; p < 0.05) was found between plasma insulin and ghrelin concentration at rest in fed subjects. Conclusions: We have concluded that plasma leptin and ghrelin concentrations have no significant effect on the fasting-induced attenuation of heart rate during exercise. We have postulated that this effect is caused by increased plasma norepinephrine concentration, leading to the increase in systemic vascular resistance and baroreceptor mediated vagal stimulation. Moreover we believe, that the fasting-induced significant increase in plasma IL-6 concentration at rest, accompanied by higher plasma norepinephrine concentration and lower RQ, belongs to the physiological responses, maintaining energy homeostasis in the fasting state.
3
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Relationship between EMG, blood lactate, and plasma catecholamine thresholds during graded exercise in men

84%
Chwalbinska-Moneta J., Kaciuba-Uscilko H., Krysztofiak H., Ziemba A., Krzeminski K., Kruk B., Nazar K.
Journal of Physiology and Pharmacology
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1998
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tom 49
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nr 3
4
Content available remote

Effects of oxygen breathing on inspiratory muscle fatigue during resistive load in cycling men

67%
Segizbaeva M. O., Aleksandrova N. P.
Journal of Physiology and Pharmacology. Supplement
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2009
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tom 60
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nr 5
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