Relationship between muscle oxygenation kinetics and the rate of decline in peak torque during isokinetic knee extension in acute hypoxia and normoxia

Yoyoi Kawahara*, Y. Salto, K. Kashimura, I. Muraoka

*この研究の対応する著者

研究成果: Article査読

12 被引用数 (Scopus)

抄録

To investigate whether low FiO2 affects muscle oxygenation and the rate of decline in peak torque (DR) during isokinetic knee extension, subjects performed 50 isokinetic knee extensions at 180°/s and at 0.5 Hz while inhaling low O2 gas (12%O2; H) or air (N). Muscle oxygenation kinetics was assessed by near-infrared spectroscopy, and wholebody V̇O2 and HR were measured. We calculated total-, oxy- and deoxy-hemoglobin/myoglobin concentrations (TotalHb/Mb, OxyHb/Mb, DeoxyHb/Mb), and the slopes of the change in OxyHb/Mb during exercise. SpO2 decreased in H while DR and V̇O2 did not differ between the conditions. During exercise, OxyHb/Mb was lower in H than in N, and DeoxyHb/Mb was higher in H than in N. TotalHb/Mb began to increase from the resting level earlier in H. HR was higher during the latter half of the exercise in H. The slopes of the change in OxyHb/Mb were the same in the two conditions. Our results show that low FiO2 decreases SpO2 and muscle oxygenation during maximal isokinetic knee extension. However, low SpO 2 and muscle oxygenation did not affect the rates of decline of peak torque. These results suggest that the decline in peak torque occurs for reasons other than O2 availability.

本文言語English
ページ(範囲)379-383
ページ数5
ジャーナルInternational journal of sports medicine
29
5
DOI
出版ステータスPublished - 2008 5月 1

ASJC Scopus subject areas

  • 整形外科およびスポーツ医学
  • 理学療法、スポーツ療法とリハビリテーション

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