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- Calbet, J, et al.
(författare)
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Why do the arms extract less oxygen than the legs during exercise?
- 2005
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Ingår i: American Journal of Physiology. Regulatory Integrative and Comparative Physiology. - : American Physiological Society. - 0363-6119 .- 1522-1490. ; 289, s. 1448-1458
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Tidskriftsartikel (refereegranskat)abstract
- To determine whether conditions for O2 utilization and O2 off-loading from the hemoglobin are different in exercising arms and legs, six cross-country skiers participated in this study. Femoral and subclavian vein blood flow and gases were determined during skiing on a treadmill at 76% maximal O2 uptake (O2 max) and at O2 max with different techniques: diagonal stride (combined arm and leg exercise), double poling (predominantly arm exercise), and leg skiing (predominantly leg exercise). The percentage of O2 extraction was always higher for the legs than for the arms. At maximal exercise (diagonal stride), the corresponding mean values were 93 and 85% (n = 3; P < 0.05). During exercise, mean arm O2 extraction correlated with the PO2 value that causes hemoglobin to be 50% saturated (P50: r = 0.93, P < 0.05), but for a given value of P50, O2 extraction was always higher in the legs than in the arms. Mean capillary muscle O2 conductance of the arm during double poling was 14.5 (SD 2.6) ml·min–1·mmHg–1, and mean capillary PO2 was 47.7 (SD 2.6) mmHg. Corresponding values for the legs during maximal exercise were 48.3 (SD 13.0) ml·min–1·mmHg–1 and 33.8 (SD 2.6) mmHg, respectively. Because conditions for O2 off-loading from the hemoglobin are similar in leg and arm muscles, the observed differences in maximal arm and leg O2 extraction should be attributed to other factors, such as a higher heterogeneity in blood flow distribution, shorter mean transit time, smaller diffusing area, and larger diffusing distance, in arms than in legs. diffusing capacity; fatigue; oxygen extraction; performance; training
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| 2. |
- Holmberg, Hans-Christer, et al.
(författare)
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Lung function and oxygen uptake during double poling, running and diagonal skiing in elite cross-country skiers
- 2007
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Ingår i: Scandinavian Journal of Medicine and Science in Sports. - : Wiley. - 0905-7188 .- 1600-0838. ; 17:4, s. 437-444
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Tidskriftsartikel (refereegranskat)abstract
- Arterial desaturation during exercise is common in endurance-trained athletes, a phenomenon often more pronounced when the muscle mass engaged in the exercise is large. With this background, the present study monitored seven international-level cross country skiers performing on a treadmill while running (RUN), double poling (DP; upper body exercise) and diagonal skiing (DIA; arm and leg exercise). Static and dynamic lung function tests were performed and oxygen uptake was measured during submaximal and maximal exercise. Lung function variables (including the diffusion capacity) were only 5-20% higher than reported in sedentary men. Vital capacity was considerably lower than expected from the skiers' maximal oxygen uptake (VO(2max)), but the maximal ventilation followed a linear relationship with VO(2max). None or only a mild desaturation was observed in DP, RUN and DIA. Blood lactate concentration was slightly higher in DIA than in DP but not different from RUN. In DIA, VO(2max) was 6.23 +/- 0.47 L/min (mean +/- SD), which was 3.8% and 13.9% higher than in RUN and DP, respectively, with similar peak heart rates for the three exercise modes. No relationships were present either between the degree of desaturation and pulmonary functions tests, or with peak oxygen uptakes. The low blood lactate accumulation during the exhaustive efforts contributed to the arterial oxygen saturation being mild in spite of the very high oxygen uptake observed in these skiers.
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| 3. |
- Holmberg, H-C, et al.
(författare)
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Lung function, arterial saturation and oxygen uptake in elite cross country skiers : influence of exercise mode.
- 2007
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Ingår i: Scandinavian Journal of Medicine and Science in Sports. - : Wiley. - 0905-7188 .- 1600-0838. ; 17:4, s. 437-44
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Tidskriftsartikel (refereegranskat)abstract
- Arterial desaturation during exercise is common in endurance-trained athletes, a phenomenon often more pronounced when the muscle mass engaged in the exercise is large. With this background, the present study monitored seven international-level cross country skiers performing on a treadmill while running (RUN), double poling (DP; upper body exercise) and diagonal skiing (DIA; arm and leg exercise). Static and dynamic lung function tests were performed and oxygen uptake was measured during submaximal and maximal exercise. Lung function variables (including the diffusion capacity) were only 5-20% higher than reported in sedentary men. Vital capacity was considerably lower than expected from the skiers' maximal oxygen uptake (VO(2max)), but the maximal ventilation followed a linear relationship with VO(2max). None or only a mild desaturation was observed in DP, RUN and DIA. Blood lactate concentration was slightly higher in DIA than in DP but not different from RUN. In DIA, VO(2max) was 6.23 +/- 0.47 L/min (mean +/- SD), which was 3.8% and 13.9% higher than in RUN and DP, respectively, with similar peak heart rates for the three exercise modes. No relationships were present either between the degree of desaturation and pulmonary functions tests, or with peak oxygen uptakes. The low blood lactate accumulation during the exhaustive efforts contributed to the arterial oxygen saturation being mild in spite of the very high oxygen uptake observed in these skiers.
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