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Działanie różnych temeperatur środowiska na poziom jodu związanego z białkiem (PBJ) i glutationu (GSH) we krwi królików

100%

Podgorski W., Szkutnik Z.

Medycyna Weterynaryjna

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1968

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tom 24

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nr 06

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Non-linear relationship between oxygen uptake and power output in the Astrand nomogram - old data revisited

71%

Zoladz J. A., Szkutnik Z., Majerczak J., Duda K., Pedersen P. K.

Journal of Physiology and Pharmacology

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2007

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tom 58

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nr 2

For the last decade there have been considerable discussion concerning the linearity / non-linearity of the oxygen uptake (O2) - power output (W) relationship with strong experimental evidence of non-linearity provided mainly by breath-by-breath measurements. In this study, we attempted to answer the question whether the O2 - W relationship in the Åstrand nomogram, as presented in the Textbook of Work Physiology, P.-O. Åstrand et al. (2003), page 281, based on the Douglas bag method, is indeed linear, as stated by the authors before, or if a change point in O2, described by Zoladz et al. (1998) Eur J Appl Physiol 78: 369-377, can possibly be detected in those data. The O2 - W data were taken from the Åstrand nomogram referenced above and from the Table 9.5 on page 282 in the same reference and tested for the presence of the change point in O2, using our two-phase model (see the reference above). In the first phase, a linear O2 - W relationship was assumed, whereas in the second one (above the so-called change point) an additional increase in O2 above the values expected from the linear model was allowed. It was found that in the data taken from the Åstrand nomogram (data for men), as well as in the data taken from the Table 9.5, statistically significant change points in O2 were present at the power output of 150 W. The documentation of the presence of a change point in the O2 - W relationship in the Åstrand data provides further evidence for the existence of a non-linearity in the O2 - W relationship in incremental exercise tests of humans, also in O2 data based upon the Douglas bag method.

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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

61%

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.

Ograniczanie wyników

2 Journal of Physiology and Pharmacology

1 Medycyna Weterynaryjna

3 Szkutnik Z.

2 Duda K.

2 Majerczak J.

2 Zoladz J. A.

1 Karasinski J.

1 Kolodziejski L.

1 Pedersen P. K.

1 Podgorski W.

1 2007

1 2006

1 1968

Działanie różnych temeperatur środowiska na poziom jodu związanego z białkiem (PBJ) i glutationu (GSH) we krwi królików

Non-linear relationship between oxygen uptake and power output in the Astrand nomogram - old data revisited

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