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

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)379-383
Number of pages5
JournalInternational journal of sports medicine
Volume29
Issue number5
DOIs
Publication statusPublished - 2008 May 1

Keywords

  • Hypoxia
  • Isokinetic knee extension
  • Near-infrared spectroscopy
  • Oxygenation

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Fingerprint Dive into the research topics of 'Relationship between muscle oxygenation kinetics and the rate of decline in peak torque during isokinetic knee extension in acute hypoxia and normoxia'. Together they form a unique fingerprint.

  • Cite this